The results showed that there was a certain correlation between the single nucleotide polymorphism of IL-10-1082G/A and rheumatic heart disease, but there was no systematic study to verify this conclusion.Systematic review of the association between single nucleotide polymorphism of IL-10-1082G/A locus and rheumatic heart disease.Computer retrieval PubMed, EMbase, Cochrane Library, CBM, CNKI, VIP and Data WanFang, the retrieval time limit from inception to June 2017. A case control study of single nucleotide polymorphisms and rheumatic heart disease in patients with rheumatic heart disease in the IL-10-1082G/A was collected. Two researchers independently screened the literature, extracted data and evaluated the risk of bias in the study, and using RevMan5.3 software for data analysis.P = 0.25; AA VS AG+GG: OR = 0.73, 95% CI , P = 0.05; AA VS GG: OR = 0.70, 95% CI, P = 0.08; AG VS GG: OR = 0.65, 95% CI , P = 0.43; A VS G: OR = 0.87, 95% CI , P = 0.17].A total of 3 case control studies were included, including 318 patients with rheumatic heart disease and 502 controls. Meta-analysis showed that there was no correlation between IL-10-1082G/A gene polymorphism and rheumatic heart disease [AA+AG VS GG: OR = 0.62, 95% CI , When AA is a recessive gene, the single nucleotide polymorphism of IL-10-1082G/A is associated with the presence of rheumatic heart disease. Due to the limitations of the quantity and quality of the included literatures, the further research results were still needed. Rheumatic heart disease (RHD) is a class of autoimmune diseases caused by beta hemolytic group A induced by Streptococcus –6. The rDomestic and foreign research results show that: RHD is a disease caused by genetic , 14, envThis study used systematic evaluation method to analyze the correlation between IL-10-1082G/A and RHD, and provide some reference for the pathogenesis and genetic susceptibility of RHD from the perspective of evidence-based medicine.Inclusion criteria: ① The correlation between IL-10-1082G/A site single nucleotide polymorphism and rheumatic heart disease; ② Study type: case control study; ③ Each study should provide a direct or indirect ratio (OR) value of the two groups of genotype frequencies; ④ Patients with rheumatic heart disease, including mitral valve disease, aortic valve disease and combined valvular disease, patient’s age, sex, combined disease, family history is not limited; In the control group, most of the patients were healthy, and the residents were randomly selected; There was no blood relationship between the subjects in each group; ⑤ The genotype distribution of the control group was consistent with the Hardy-Weinberg (H-W) genetic equilibrium; ⑥ Research object is human.① Perspective study; ② Repeated reports; ③ Abstracts, reviews, and information is not all in the form of abstracts; ④ Zoopery; ⑤ Information is incomplete or unable to extract the data from the literature.All the subjects were used to retrieve the database. English search terms was rheumatic heart disease, disease, rheumatic heart or diseases, IL-10-1082, mutation, polymorphism, variant, as shown in Table Two researchers independently screened the literature, extracted data and evaluated the risk of bias in the study. In case of disagreement, discuss the solution or hand in the decision by the third party. Extracting data from the data of self-made data. The main contents including: ① Included in the study of the basic information, including research topics, the first author, published a magazine and time, etc; ② Key elements of risk assessment of bias; ③ Distribution frequency of genotype in case group and control group; The bias risk was evaluated by NOS scale .P < 0.05, then the control group genotype does not meet HWE. Then 5 genetic models were calculated, respectively, including dominant model (AA+AG vs GG), implicit model (AA vs AG+GG), codominant model (AA vs GG), codominant model (AG vs GG) and Allele model (A vs G). The OR value and its 95%CI were used to analyze the effect of combined analysis, and the test level of = 0.05 was analyzed by Meta. The heterogeneity between the results was using the chi square test for analysis , and combined with I2 quantitatively determine the size heterogeneity. If the research results were not statistically different, the fixed effect model was used for Meta-analysis. If the research results were statistically different, the random effects model was used to analyze the effects of Meta on the exclusion of significant clinical heterogeneity. Obvious clinical heterogeneity was treated by subgroup analysis, such as the different subgroups of ethnic groups, or sensitivity analysis, and other methods of treatment, or descriptive analysis . As shown in Figure Dominant model (AA+AG vs GG). A total of 318 cases and 502 controls were included. With the genotype AA+AG as the exposure factor, the genotype GG was the non-exposure factor. Fixed effect model meta-analysis showed that I2 = 84%, P = 0.002. There is a large heterogeneity, so we use a random effects model. Random effects model meta-analysis showed that there was no association between the polymorphism of the gene and RHD . As shown in Figure Implicit model (AA vs AG+GG). A total of 318 cases and 502 controls were included. With the genotype AA as the exposure factor, the genotype AG+GG was the non-exposure factor. Fixed effect model meta-analysis showed that I2 = 0%, P = 0.81, the heterogeneity was small, so we use a fixed effect model. Fixed effect model meta-analysis results showed that there was no association between the polymorphism of the gene and RHD . As shown in Figure Codominant model (AA vs GG). A total of 168 cancer patients and 268 controls were included. With the genotype AA as the exposure factor, the genotype GG was the non-exposure factor. Fixed effect model meta-analysis showed that I95% CI 0.7, 1.05, 2 = 85%, P = 0.001, there is a large heterogeneity, so we use a random effects model. Random effects model meta-analysis showed that there was no association between the polymorphism of the gene and RHD . As shown in Figure Codominant model (AG vs GG). A total of 230 cancer patients and 334 controls were included. With the genotype AG as the exposure factor, the genotype GG was the non-exposure factor. Fixed effect model meta-analysis showed that I2 = 0%, P = 0.93, the heterogeneity was small, so we use a fixed effect model. Fixed effect model meta-analysis results showed that there was no association between the polymorphism of the gene and RHD . As shown in Figure Allele model (A vs G). A total of 308 patients and 502 controls were included. The allele G was the exposure factor, and the allele A was non-exposure factor. Fixed effect model meta-analysis showed that I0.71, 1.0, P = 0.1Interleukin 10 (IL-10) is a newly discovered cytokine in recent years, also known as cytokine synthesis inhibitory factor, with 178 amino acid residues in a single chain glycoprotein  –35. IL-1Interleukin-10 (IL-10) is an important inflammatory factor in the body –39. It hThe study included 3 case-control studies, a total of 318 patients with rheumatic heart disease and 502 control subjects. Our results showed that the IL-10-1082G/A polymorphism in the Implicit model (AA vs AG+GG) has a certain correlation with the risk of rheumatic heart disease, but dominant model (AA+AG vs GG), codominant model (AA vs GG), codominant model (AG vs GG) and Allele model (A vs G) have no associated with the risk of rheumatic heart disease. In this study, we found that there is a certain heterogeneity among the studies, which may including: ① The cases and controls involved in the study were derived from different regions, ethnic, and the Inclusion criteria among case group and control group are not agreement; ② The article Included in the study were published in the literature, not included the gray literature; ③ Different types of disease diagnosis methods from different countries or regions are different, which may bring about a certain heterogeneity.The limitations of this study including: ① the incidence of rheumatic heart disease is related to many factors. But in this study, the correlation between one gene polymorphism and rheumatic heart disease was studied, and the interaction of gene and gene environment was analyzed, and the interaction of gene and gene environment was analyzed. ② Because of the small number of the included studies, the study was not further divided into subgroups according to the type of disease and race. If there are more studies in the future, we will further study the correlation between different types of disease and race. ③ The Meta analysis was included in the study population for the African population, and did not incorporate studies from Europe, Asia, and North America. So the conclusions of this study may not be applicable to people in Europe, Asia and North America.In conclusion, this study found that the polymorphism of IL-10-1082G/A gene may be related to the risk of rheumatic heart disease. Due to the quantity and quality of the research, the conclusions of this study need to be carried out to verify the quality of the large sample.


To collectively evaluate the association between haptoglobin (Hp) gene variants and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).  A comprehensive literature review was performed for eligible studies. After inclusion and exclusion selection as well as quality assessment, those studies meeting quality standards were included. In this study, diabetic patients with retinopathy were selected as the case group and those ones without DR were treated as the control group. The recessive model, allele model, additive model, heterozygote model, and homozygote model were utilized to investigate the association of three Hp gene variants and DR. Subgroup analysis on different severity of DR including nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) was also conducted.  Six trials from different regions were finally included. A total of 1145 subjects containing 564 T2DM patients with retinopathy were included. The recessive model, allele model, additive model, and homozygote model results showed that Hp gene variants were not associated with DR, NPDR, and PDR. However, the heterozygote model indicated the association of Hp gene variants with DR.  No association was found between the Hp gene variants and PDR and NPDR. More studies are required to verify these findings. Diabetes is a global health burden that affects populations' economic and health status. Due to the fact that diabetes is a system metabolic disorder, many organs and tissues will be affected and might be in dysfunction in the end. Management of diabetic complications has been a worldwide research of interest due to its clinical relevance and importance –3. VascuTraditional measures to detect those microvascular complications mostly relied on imaging techniques. A digital fundus camera is such a device that could be utilized to record retinal blood vessels, the images of which are further assessed by ophthalmologists qualitatively. Besides biomarkers at the observable tissue level, some biomarkers at the molecular level are probably involved in the progression of above-mentioned microvascular complications. Heritability estimates for DR range from 25 to 50%, and the same degree of DR has been found in a cohort of identical twins with diabetes, suggesting that genetic variation is associated with DR. Haptoglobin (Hp) gene rs137853233) is one of such candidate genes and is encoded by a single gene on chromosome 16. Hp gene has been discovered in human serum since 60 years ago, and the genetic mutation could be identified using SNP genotype data 853233 is–12. Ther∗, glycuresis; (ii) haptoglobin, Hp, Hp∗, gene, genetic, Hp1-1, Hp1-2, Hp2-1, Hp2-2; (iii) incidence, mortality, epidemiologic studies; and (iv) photography, photomicrography, photo$, image$, retinopathy, fundus. We combined the terms to generate a subset of citations that address the objective of our research study. We also hand searched reference lists of relevant articles for eligible studies. We examined the reference lists of all known primary and review articles to identify additional articles not captured by the electronic searches. The detailed search strategy is available from the authors. Two reviewers (Wu and Wu) independently examined the electronic searches and obtained full reports of all citations that were likely to meet the predefined selection criteria. Disagreements were resolved by consensus after discussion with a third reviewer (Yin).In the research, a comprehensive literature review was performed on four electronic databases: PubMed , ISI (Web of Science), Embase, and CNKI , and the related studies published in English or Chinese before January 2017.While conducting the searches in the databases, no restrictions were imposed for time and language. Two subsets of citations were enhanced, namely, an indexing DR or diabetes, the other indexing Hp. For developing these subsets of citations, we used a combination of subject headings and text terms used in medical literature. Search terms used were as follows: (i) diabetic retinopathy, DR, diabetes without retinopathy, DWR, proliferative diabetic retinopathy, PDR, non-proliferative diabetic retinopathy, NPDR, metabolic syndrome, diabetic complication, diabetes, diabeThe inclusion criteria were as follows: (i) case-control or cohort studies published about the association of Hp gene variants and DR in patients with the T2DM disease. (ii) Determination of DR was made by ophthalmoscope examination or fundus photography. (iii) Adequate information about the Hp genotype and allele were available. (iv) The language was written in English or Chinese.The exclusion criteria were as follows: (i) insufficient data in frequencies of Hp genotype and allele, (ii) insufficient information about baseline characteristics of participants, (iii) literature reporting language other than English and Chinese, and (iv) patients diagnosed with T1DM other than T2DM.I2. In general, intergroup heterogeneity was evaluated by inconsistency index (I2) and heterogeneity. While the heterogeneity value was less than 0.1, pooled OR was estimated by using a random effect model or otherwise using a fix effect model. Sensitivity analyses were performed by omitting each study to identify possible study contributing to the heterogeneity. A two-sided value which is less than 0.05 means statistically significant. Funnel plots were utilized for investigating publication and other biases in meta-analysis.In this study, those studies meeting the quality standards were included. The quality of the included studies was assessed by their risk of bias, directness, consistency of results, precision, publication bias, the magnitude of the effect, and so forth. In each of the included studies, three individual researchers  independently extracted the raw data associated with the values of Hp gene variants, DR numbers, total study numbers, ages, sex, and other factors. In instances where the raw data could not be extracted or calculated, we obtained the same by contacting the authors of these manuscripts. The recessive model, allele model, additive model, heterozygote model, and homozygote model were utilized to investigate the association of Hp gene variants and DR. For improving the accuracy of these tests, subgroup analyses were used to identify the test-related or other factors responsible for heterogeneity. In this study, RevMan (version: 5.2) was used to perform meta-analysis. Odds ratio (OR) and its 95% confidence interval (CI) were calculated for statistical analysis. Heterogeneity was established using chi-square and quantified by The literature search yielded 295 references, six articles –18 out oA total of six trials were retrieved for detail data extraction . The sixX2 p = 0.01 < 0.05, I2 = 73%); the total effect size OR in this study was 1.11 , and the Z value was 0.14 (p > 0.05), suggesting that Hp gene variants were not associated with DR ; the total effect size OR in this study was 0.80 , and the Z value was 0.70 (p > 0.05), suggesting that no association was found between the Hp gene variants and DR ; the total effect size OR and Z value were 0.74  and 0.81 (p > 0.05), respectively, indicating that Hp gene variant was not associated with DR either ; the total effect size OR in this study was 2.39 , and the Z value was 2.39 (p < 0.05), suggesting that Hp gene variants were associated with DR , and the Z value and the total effect size OR are both suggesting that Hp gene variants were not associated with DR ; the subtotal effect size OR in this study was 2.23 , 1.74 , and 2.21 , respectively, all suggesting that Hp gene variants were not associated with NPDR , and the subtotal effect size OR in these studies was 0.96 , 0.60 , 0.99 , 0.66 , 0.53 , and 1.19 , respectively, all suggesting that Hp gene variants were not associated with PDR .Funnel plots of each group of meta-analysis were shown, and those funnel plots without outlines were due to the use of the random effect model . Figure S2. Funnel plot for Meta analysis comparing DR with DWR in allele model (T vs C). Figure S3. Funnel plot for Meta analysis comparing DR with DWR in recessive model(TT vs CT + CC). Figure S4. Funnel plot for Meta analysis comparing DR with DWR in heterozygote model(TC vs CC). Figure S5. Funnel plot for Meta analysis comparing DR with DWR in homozygous model (TT vs CC). Figure S6. Funnel plot for Meta analysis comparing DR with DWR in additive model(TT + CC vs CT). Figure S7. Funnel plot for Meta analysis comparing NPDR with DWR in different models. Figure S8. Funnel plot for Meta analysis comparing PDR with DWR in different models.


FOXO1 , RXRA-COL5A1 , FNDC3B , IMMP2L , and BANP-ZNF469 . The gene COL4A4  was identified in previous candidate gene studies. We also found SNPs in 10 genes/loci that had a summary P value < 0.05. Sensitivity analysis indicated that the results were robust. Replication studies and understanding the roles of these genes in keratoconus are warranted.Genetic associations for keratoconus could be useful for understanding disease pathogenesis and discovering biomarkers for early detection of the disease. We conducted a systematic review and meta-analysis to summarize all reported genetic associations for the disease. We searched in the MEDLINE, Embase, Web of Science, and HuGENET databases for genetic studies of keratoconus published from 1950 to June 2016. The summary odds ratio and 95% confidence intervals of all polymorphisms were estimated using the random-effect model. Among 639 reports that were retrieved, 24 fulfilled required criteria as eligible studies for meta-analysis, involving a total of 53 polymorphisms in 28 genes/loci. Results of our meta-analysis lead to the prioritization of 8 single-nucleotide polymorphisms (SNPs) in 6 genes/loci for keratoconus in Whites. Of them 5 genes/loci were originally detected in genome-wide association studies, including  It is a leading indication for corneal transplantation in many countries, especially in Australia, Middle East and Africa3. Management of keratoconus varies from conservative visual correction by spectacles or contact lenses for mild disease, to surgical interventions such as collagen cross-linking, intracorneal rings and keratoplasty for advanced disease. The onset of keratoconus is insidious and the progression is irreversible. Therefore, early diagnosis of keratoconus and its progression is needed. However, the variable risk of keratoconus progression poses a challenge to the personalized management for patients4. Knowing the risk factors for keratoconus would thus be helpful for early detection and monitoring the progression of the disease.Keratoconus is a noninflammatory degenerative disorder that results in bulging and distortion of the corneal surface, leading to irregular astigmatism and progressive myopia. In advanced cases, corneal scarring and even corneal blindness can occur. Keratoconus has an incidence of approximately 1 in 2,000 individuals with a prevalence varying from 8.8 to 2300 per 100,0005 and chronic eye rubbing6. The genetic aetiology is evidenced by the bilaterality, familial aggregation9, monozygotic twins concordant of the disease10, its association with other genetic diseases such as Down syndrome11 and Leber’s congenital amaurosis12, and the ethnic difference in the prevalence and incidences13. Genetic associations for keratoconus will provide insight into disease mechanisms and help identify biomarkers for early detection of keratoconus onset and monitoring its progression. Of note, about 14% of the patients with keratoconus have a family history9. So far, however, the difference in the genetic basis of familial and sporadic keratoconus is unclear. Since the family history does not affect disease severity, the pooling of all cases in genetic studies is deemed reasonable14.Keratoconus is a multifactorial disease resulting from the interaction of environmental, behavioural and genetic factors. Major environmental and behavioural factors include contact lens wear2p2415, 3p14-q1316, 5q14.3-q21.12, 13q3218, 16q22.3-q23.119, and 20q1220. However, no disease-causing mutation has been identified from these loci. Besides, genome-wide association studies (GWAS) and candidate gene association studies have reported over 150 polymorphisms in more than 60 genes/loci for keratoconus. Among them, 7 genes/loci were identified by GWAS, including the HGF21, LOX22, FOXO1 and FNDC3B genes23, and the 3p26, 2q21.3 and 19q13.3 loci24. However, most of these associations were inconsistent across different study cohorts, making the roles of the genes/loci inconclusive.So far, 6 chromosomal loci have been identified for isolated keratoconus by linkage analysis, namely In this study, we conducted a systematic review and meta-analysis to summarize the genetic association evidence for all variants in genes that were previously reported for keratoconus, and evaluated potential trans-ethnic heterogeneities. We first presented the association results from selected original studies/cohorts in the forest plots and then provided a prioritized list of studies and genes variants for further analysis. For SNPs that have been meta-analyzed in prior studies, our study provides an update of the summary association results by including new studies.26 and 32 were molecular genetic studies, including 2 GWAS24 and 30 candidate gene association studies. A total of 64 genes/loci and 156 variants have been identified from the full-text review , RXRA-COL5A1 rs1536482 , and FNDC3B rs4894535  (Table −7 (IMMP2L rs757219) to 0.035 (19p12 rs8111998) , while FOXO1 rs2721051 , BANP-ZNF469 rs9938149 , COL4A4  and COL4A3  were nominally significant  were also insignificant , MPDZ-NFIB rs1324183 , BANP-ZNF469 rs9938149 , COL5A1 rs7044529  and HGF rs3735520  = 2.38; I2 = 0) and rs2228557  (Supplementary Table 2 = 16%). The odds ratio was notably toward an opposite direction , BANP-ZNF469 rs9938149 , MPDZ-NFIB rs1324183 , and COL5A1 rs7044529  . The 5 SNPs that were identified from GWAS showed a robust or nominal significance in Whites: In this study, we were not able to evaluate the potential difference in the genetic basis of familial and sporadic cases as the data from familial cases were limited.FOXO1 (rs2721051)56, COL4A3 (rs10178458 and rs55703767)52, COL4A4 52, and VSX1 (rs12480307)45. Therefore, in the sensitivity analysis we first excluded all the cohorts with HWE deviation and recalculated the summary ORs for the 7 SNPs in 4 genes. The associations were not altered (Supplementary Table COL4A3 (rs55703767), LOX (rs2956540) and VSX1 (rs6138482) in the subgroup analysis by ethnicity  showed consistent effects with low heterogeneity across different study cohorts. Three of them, FOXO1 rs2721051, FNDC3B rs4894535 and BANP-ZNF469 rs9938149, have been tested in both Whites and Asian populations. However, none of them showed a significant association in Chinese32 or Arabs40. Of note, FOXO1 rs2721051 was rare in Chinese with a minor allele frequency of 0.1%32. The lack of significant association in Asians could be due to the small sample size. In this meta-analysis, we also identified a SNP rs2229813 in the COL4A4 gene that showed a summary P value of genome-wide significant in Whites . This gene was identified only in candidate gene studies52. Interestingly the summary P value in the pooled non-Caucasian samples was nominally significant (P = 0.047), but the OR was toward the opposite direction (OR = 0.74). This may suggest trans-ethnic diversities in the genetic components of keratoconus. In the COL4A4 gene, another SNP rs2228557, which was proposed in candidate gene studies, showed a significant summary P value (P = 4.5 × 10−7) in Whites, suggesting COL4A4 could be a genuine susceptibility gene for keratoconus in Whites. However, rs2228557 has only been tested in a Chinese population showing an insignificant association with an opposite OR (1.09)45. Therefore, whether COL4A4 is a biomarker with differential effects on keratoconus among different ethnic groups has yet to be confirmed. Interestingly, these 2 SNPs  have not been reported in the published GWAS papers. In GWAS, only SNPs with P values surpassing a certain threshold would have been subjected to replication. Therefore, it would be intriguing to check the COL4A4 SNPs in the GWAS data and assess their association with keratoconus.Among the 6 significant genes/loci for keratoconus, 5 were originally identified by GWAS, including 55. In 3 studies55, the authors tested the associations of a few genes/loci (e.g. LOX and COL5A1) with keratoconus in a familial cohort using a generalized estimating equation accounting for familial correlations. Some of the significant SNPs identified in unrelated cases also showed significant association with keratoconus in the familial cohort. In another 2 studies51, the authors reported a mutation, “627 + 23 G > A”, in VSX1 that was segregated in cases in several families. However, the mutation did not show significant association with keratoconus in the analysis using all the cases50. The results from the 2 cohorts indicated that the genetic association profiles of sporadic and familial keratoconus could be different.Although we were not able to evaluate the potential difference in the genetic basis of familial and sporadic cases, we found 2 familial cohorts being tested for different genes/lociFOXO1, RXRA and FNDC3B are the 3 genes that showed genome-wide significant association with keratoconus. FOXO1 is a member of the Forkhead Box (Fox) transcription factor family. Proteins from this family contain a conserved forkhead domain, which is a 110 amino acid DNA-binding domain. Fox proteins are known to be important regulators of the cellular oxidative stress57. For example, Fox proteins regulate the expressions of anti-oxidative enzymes such as superoxide dismutase and thioredoxin reductase59. Moreover, reduced FOXO1 expression has been reported to induce apoptosis in human trabecular meshwork cells in response to oxidative stress60. It has been shown that increased oxidative damage to trabecular meshwork cells results in elevation of intraocular pressure and changing the anterior chamber angle, which would lead to corneal thinning61. We also found association of keratoconus with IMMP2L, a mitochondrial inner membrane protease. Mutation in IMMP2L also accumulates oxidative stress62. Therefore, FOXO1 and IMMP2L might regulate the oxidative stress in the anterior chamber, which affects the intraocular pressure and the corneal thickness. FOXO1 has also been linked to adipocyte differentiation63, which is affected by the gene FNDC3B64. In this study, FNDC3B is another keratoconus associated gene. The link between adipogenesis and keratoconus is currently unclear. However, FNDC3B was associated with elevated intraocular pressure in a GWAS study65. Hence, FNDC3B may influence the intraocular pressure, the anterior chamber angle and the corneal thickness. Another keratoconus gene is RXRA, which encodes a nuclear retinoic acid receptor protein. There are two classes of nuclear retinoic acid receptors: RXR and RAR, which bind to each other to form RXR/RAR heterodimers66. Null mice of both RXRA and RXRA/RAR showed abnormal embryonic eye morphologies, including thickening of corneal stroma and absence of anterior chamber66. These results suggest a potential role of RXRA and retinoic acid signaling in the ocular development. However, the link among retinoic acid signalling, ocular development, and the abnormal corneal in keratoconus remains to be explored.Results of the present meta-analysis have led to a list of genes and loci associated with keratoconus that can be considered for functional investigations. Further biological investigation on these genes may throw light on new disease mechanisms for keratoconus. For example, HGF, rs3735520 (c.−1652C > T), was reported to modulate the severity of interstitial lung disease in patients with systemic sclerosis by altering the transcriptional efficiency of the HGF gene67. Whether they are in linkage disequilibrium with other coding variants in the relevant genes remained to be elucidated by sequencing analyses.It is noteworthy that all of the identified SNPs in the 16 genes/loci are located in intronic, inter-genic, or in 3′- or 5′-untranslated regions. One SNP in COL5A1 for Ehlers-Danlos syndrome68; COL4A3 and COL4A4 for Alport syndrome69; HGF for non-syndromic hearing loss70; IMMP2L for Gilles de la Tourette syndrome71; KCND3 for spinocerebellar ataxia72; LOX for thoracic aortic aneurysms and dissections73; MPDZ for leber congenital amaurosis and retinitis pigmentosa74; RAB3GAP1 for Warburg Micro syndrome and Martsolf syndrome75; and ZNF469 for Brittle cornea syndrome76. The other 6 of the 16 identified genes, namely FOXO1, RXRA, FNDC3B, BANP, UBXD2, and NFIB of the MPDZ-NFIB locus, have not been directly linked to other human diseases.Although the mechanisms underlying the significant associations of the 16 identified genes/loci with keratoconus are largely unknown, it might be useful for understanding their pathogenic effects by referring to disease pathways identified for other conditions that share the same genes/loci. Eleven genes have been implicated in other diseases, including: COL4A4 variants might not reach the genome-wide significance in the reported GWAS. The non-availability of the data for these variants could be a potential source of publication bias.In this study, we have identified and evaluated the genetic associations for keratoconus by conducting thorough assessments of the existing evidence. We have taken multiple measures to control for potential biases, including subgroup analysis, sensitivity analysis, and Egger’s test. However, this study has some limitations. First, our results could be more applicable to Whites, therefore most of the significant findings should be replicated in other populations with sufficient statistical power, such as the Asian populations. Second, the sample sizes in most of the candidate gene studies were small, especially in Asian populations. We observed lack of associations of almost all SNPs when summarizing the data from Asian cohorts. Therefore, larger cohorts are needed for further validation. Third, although we employed funnel plots and Egger’s tests to identify publication bias, there could still be remaining publication bias due to the reduced power when testing small number of studies in a meta-analysis. Moreover, the FOXO1 rs2721051, RXRA-COL5A1 rs1536482, FNDC3B rs4894535, IMMP2L rs757219 and rs214884, and BANP-ZNF469 rs9938149, and COL4A4 rs2229813 and rs2228557. We also identified 10 genes/loci with suggestive evidence of association with keratoconus. This study has thus provided an up-to-date list of candidate genetic markers for further investigations of their biological roles in keratoconus. More studies are warranted to confirm the reported genetic associations in different populations.In conclusion, we have prioritized 8 SNPs in 6 genes/loci as significant genetic markers for keratoconus in Whites, including We searched for relevant records in the MEDLINE, Embase, Web of Science, and HuGENET databases via the Ovid platform. We used the Boolean logic to connect the free terms and controlled vocabularies : (“polymorphism(s)” OR “mutation” OR “genotype(s)” OR “genetic(s)” OR “gene(s)” OR “allele(s)” OR “DNA”) AND (“keratoconus”)  original case-control studies that evaluated the association of gene polymorphisms with keratoconus; (2) the study subjects were unrelated and recruited from explicitly defined populations; and (3) allele or genotype counts or frequencies in both case and control groups were reported or calculable; or odds ratio and 95% confidence intervals (CI) and/or standard error (SE) were reported. We excluded animal studies, case reports, reviews, abstracts, conference proceedings, and editorials.24. For candidate gene study, we extracted all the reported variants. No significance threshold for the genetic association has been applied during the data extraction. We also checked for potentially duplicated cohorts among the studies via comparing research groups and description of study populations. In the studies that had reported 2 or more independent cohorts, we extracted the data of each cohort separately. Second, we selected those polymorphisms that could be meta-analyzed. Third, the missing allele/genotype counts were calculated using the allele frequencies and sample sizes, assuming no deviation from HWE unless reported otherwise77. If only the OR and 95% CI were reported, we estimated the SE following the methods described in our previous papers78. We attempted to contact the authors for additional information if necessary. If the HWE result was not reported, we tested it using the extracted data in the control group by the Chi-square test. Moreover, we used the NOS system  to evaluate the quality of the case-control studies . The maximum number of stars that a study could obtain was 8. A study of <5 stars in overall or earned no star in any one of the items  was considered as of suboptimal quality and having high risk in introducing bias81.Two reviewers (S.S.R. and S.T.U.M.) independently screened all the titles and abstracts of identified studies. Disagreements were resolved via discussions with a senior investigator (L.J.C.). After identifying potentially eligible articles, the 4 reviewers  extracted the data separately and cross-validated the data. Consensus was reached via thorough discussion among all the reviewers. In this study, we used ‘Whites’ to represent individuals/populations whose ancestral origins are in the continent of Europe. We designed a customized datasheet for data extraction, which included the first author, year of publication, country of study, ethnicity, definition of case and control, sample sizes in the case and control groups, genes/loci, polymorphisms, allelic and genotypic counts and frequencies, ORs and 95% CIs or SEs of the polymorphisms and corresponding genetic models, and results of the test for HWE in the control group. First, we extracted all the polymorphisms and genes/loci reported in the potentially eligible studies searchable by the end of our search date. For GWAS, we extracted all the variants that were shown to be tested in replication cohorts in the result section and supplementary tablesI2 82. An I2 value of lower than 25%, between 25% and 50%, and greater than 50% indicated low, moderate, and high heterogeneity, respectively. However, to obtain more conservative results we calculated the summary OR and 95% CI for each SNP only using the random-effect model, in which the weighted effect of a SNP was estimated by inverse variance (IV) and τ2 from the DerSimonian-Laird estimator83, regardless of the Q statistics and I2. Of note, to assess the replication results of SNPs identified in the GWAS on keratoconus24, we first combined the data from both the GWAS and replication studies, and then removed the data from the initial GWAS. Subgroup analysis by ethnicity was then conducted in Whites and Asian populations . We adopted the funnel plots and Egger’s test to assess potential biases (e.g. publication bias)85. A P value of <0.05 in the Egger’s test indicated statistically significant bias. We also conducted the sensitivity analysis to confirm the associations by sequentially omitting each of the included studies one at a time and recalculated the summary outcomes. We then omitted the studies that deviated from HWE (PChi-squre ≤ 0.05), or of suboptimal quality. A finding is more likely to be true when the result is stable in the sensitivity analysis.We conducted meta-analysis for the SNPs that had been reported in 2 or more study cohorts from at least 2 separated reports. The genetic association was assessed using the allelic (a vs. A) model, where “a” and “A” represented the associated and the reference alleles, respectively. We evaluated the inter-cohort heterogeneity using the http://cran.r-project.org/) were generated for the meta-analysis.Customized analytical scripts based on the metafor package in the R software  and also by the maximum number of different tests a SNP could be done (N = 7). The adjusted significant threshold was therefore 1.35 × 10Supplementary information


CD152) gene have been reported to be associated with breast cancer (BC), but relevant findings were far from conclusive. Therefore, we carried out this meta-analysis to combine those results for a clearer perspective on this issue.The polymorphisms in cluster of differentiation 152 . The strength of association was evaluated with pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs). Heterogeneity evaluation was conducted via Q test. Sensitivity analysis was used to detect the stability of our results. Begg's funnel plot and Egger's test were applied to investigate publication bias among selected studies.Online databases and other sources were searched for published studies on the relationship between BC susceptibility and The polymorphisms +49 G/A, −1661 A/G and −318 C/T may elevate the susceptibility to BC, but the polymorphism CT60 G/A may offer protection against the cancer. Breast cancer (BC) is the most commonly diagnosed malignancy and a leading cause of cancer-related deaths in women around the world , 2. The CD152 gene is located on chromosome 2q33, and contains 4 exons coding for a leader sequence, an extracellular domain, a transmembrane domain and a cytoplasmic tail [CD152 has been identified to possess numerous polymorphisms, including −1661A/G, −1722T/C, −318C/T, +49A > G and CT60G/A [CD152 gene [Cluster of differentiation 152 (CD152), also know as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), is a homologue of CD28, and functions as an inhibitor receptor for B7 which is a co-stimulatory molecule on mature antigen-presenting cells , 11. CD1mic tail . As a hi152 gene , and the152 gene . Therefo152 gene  and cancCD152 gene have been discussed their relationship with the susceptibility to BC in previous studies, but relevant findings were conflicting. So we performed this meta-analysis to pool these results for a more comprehensive conclusion.The polymorphisms +49 G/A (rs231775), −1661 A/G (rs4553808), −1722 T/C (rs733618), −318 C/T (rs5742909) and CT60 G/A (rs3087243) in the Altogether, 75 potentially relevant publications were initially retrieved using the searching strategy. After strict screening, 67 of them were excluded for not conforming to the criteria above mentioned Figure , and finCD152 gene, three of them were related to increased risk of BC and one was negatively associated with the cancer susceptibility, while the other one showed no significant relationship under any one of genetic contrasts. Specifically, the polymorphism +49 G/A elevated the risk of BC under all five contrasts of AA vs. GG .Begg's funnel plot and Egger's test were employed to inspect publication bias across included studies. As a result, the shape of funnel plots seemed symmetrical Figure , implyinBC is the most frequent malignancy in women all over the world. The incidence rate of BC in China is lower than that in western countries, but it still shows a rising trend in the past few years, especially in those big coastal cities of this country. With complex pathogenesis, multiple factors may contribute to the occurrence and development of BC. Many elements have been identified as potential risk factors for BC onset, such as positive familial history of BC, history of benign breast diseases, excessive exposure to ionizing radiation, early menarche, alcohol consumption, and excessive intake of saturated fatty acid and meat. However, among people exposing to the same environment and having similar lifestyle, only a part of them develop to BC. Although the initiation and progression of the majority of human cancers have been shown to be the results of combined actions between environmental and genetic factors, some studies demonstrate that heredity contributes to about one fourth of all BC cases. All these phenomenons imply that genetic factors play a critical role in the initiation of BC.CD152 gene consists of 4 exons and 3 introns, with more than 100 polymorphisms. These polymorphisms may alter the expression and/or the activity of the protein, thus being involved in the etiology of multiple diseases.As one of the most fundamental immunosuppressive cytokines, CD152 is mainly expressed on activated T cells. It functions as a restraining regulator for the proliferation and activation of T cells, further inhibiting the immune functions of T cells through inducing Fas-independent apoptosis of activated T cells. Additionally, CD152 is also expressed on different cellular types, both normal and neoplastic. CD152 can suppress cell-cycle progression through inhibiting interleukin-2 production, thus resulting in the induction and maintenance of T cell tolerance. The CD152 molecule can reduce the responses of T cells to foreign antigens and autoantigens under physiological conditions. It is up-regulated on the surface of the latter in tumor microenvironment. Besides, CD152 deficiency can lead to lethal diseases, including cancer. CD152 gene and the susceptibility to BC. Wang et al. found that the −1661 A/G polymorphism G allele, the −318 C/T polymorphism T allele and the CT60 G/A polymorphism G allele were more frequent in BC patients than that in controls. They concluded that these alleles increased the risk of the cancer, while the +49G/A polymorphism was only associated with tumor size in the patients [In the previous tumor investigations, a number of studies were carried out to estimate the association between the polymorphisms  of patients . For −16patients . Howeverpatients .CD152 polymorphisms and BC susceptibility, which is the reason for us to perform this meta-analysis. Pooled analysis demonstrated that the +49 G/A, −1661 A/G and −318 C/T polymorphisms could increase the risk of BC, while CT60 G/A polymorphism exerted an opposite function on the susceptibility to the malignancy. Meanwhile, −1722 T/C polymorphism did not show significant link with the cancer developing. The results were obtained based on strict analyses, but they still need to be identified by studies with larger sample sizes, due to some limitations in this meta-analysis. Firstly, the number of included studies was small, which might affect the comprehensiveness of the final outcomes. Secondly, subgroup analysis was not performed in the present study due to limited data. Thirdly, as we all know, BC was a complicated diseases caused by multiple factors and interactions among them, but this respect was not explored in our meta-analysis.Based on Asian populations, these studies got no consistent opinion on the relationship between CD152 gene have a positive relationship with BC susceptibility while the CT60 G/A polymorphism is negatively related to the cancer.In summary, the +49 G/A, −1661 A/G and −318 C/T polymorphisms of the CD152 polymorphisms and BC risk, using the combination of key terms as followed: “Cluster of differentiation 152′′ or “CD152” or “cytotoxic T-lymphocyte-associated protein 4” or “CTLA-4′′ or “ALPS5” or “GSE”, “breast cancer” or “breast carcinoma” or “mammary cancer”, and “polymorphism” or “mutation” or “variant”. Additionally, other sources and reference lists of relevant reports were also checked to supplement the results of database searching.The electronic databases of PubMed, EMBASE, Google Scholar Web, CNKI and Wanfang were searched for studies on the association between CD152 polymorphisms and BC susceptibility; stating sufficient data on genotype and/or allele frequencies of studied polymorphisms both in case and control groups for calculating odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs); and published in English or Chinese language. As for excluded publications, they met at least one of the following conditions: based on duplicated data; focusing on animals; and letters, commentaries, case report, review articles or conference abstracts. When the same group of study participants was incorporated into more than one report, the one with the largest sample size or most recently published was selected.The pre-designed criteria for each included study were as followed: with a case-control design; assessing the relationship between the P value for Hardy-Weinberg equilibrium (HWE) in controls. Any discrepancies over extracted data were settled through discussion between the two reviewers; if no consensus was reached through such approach, a third reviewer would be invited into the discussion.Two independent reviewers were in charge of extracting primary information from all eligible articles using the same data table. Essential information abstracted contained first author's name, publication year, original country, ethnicity, genotyping method, number of cases and controls, genotype and/or allele frequencies in case and control groups, and CD152 polymorphisms and BC susceptibility was appraised through calculating pooled ORs and their 95% CIs. Heterogeneity between included studies was detected with Q test. P < 0.05 suggested significant heterogeneity, and the random-effects model was used; otherwise, the fixed-effects model was applied to assess the combined results. Sensitivity analysis was performed by omitting one study each time. Between-study publication bias was examined with both Begg's funnel plot and Egger's regression test. All these statistical analyses were completed with STATA 12.0 software .The intensity of the association between


Myosin IXB (MYO9B) gene polymorphisms have been extensively investigated in terms of their associations with inflammatory bowel disease (IBD), with contradictory results. The aim of this meta-analysis was to evaluate associations between MY09B gene polymorphisms and the risk of IBD, Crohn's disease (CD) and ulcerative colitis (UC). Eligible studies from PubMed, Embase, and CNKI databases were identified. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Ten studies published in eight papers reporting 8,975 cases and 9,482 controls were included in this meta-analysis. Five MY09B gene polymorphisms were evaluated: rs1545620, rs962917, rs1457092, rs2305764, and rs2305767. Our data suggested that the rs1545620 polymorphism was associated with a decreased risk of IBD. A similar result was found for rs2305767 and UC. The rs962917 single nucleotide polymorphism (SNP) increased the risk of IBD, CD and UC. Moreover, rs1457092 increased the risk of IBD and UC. Rs2305764 was also associated with an increased risk of IBD. Furthermore, stratification analyses indicated that rs1545620 decreased the risk of IBD, while rs962917 increased the risk of IBD, CD and UC in Caucasian populations. To sum up, our data indicate that these five SNPs in MY09B are significantly associated with the risk of IBD. Althoug ATG16L1 . Genome- ATG16L1 , 6.Myosin IXB (MYO9B) encodes a single-headed processive myosin that is a member of the class IX myosin family [MYO9B as a susceptibility gene for celiac disease [MYO9B lies on chromosome 19p13.1, which has been linked to both celiac disease [MYO9B has been shown to be associated with IBD [MYO9B may be a candidate susceptibility gene for IBD.n family . MY09B in family . Studies disease . MYO9B l disease  and IBD  disease . Autoimmwith IBD . TherefoMYO9B gene polymorphisms and IBD susceptibility, but with discordant results [MY09B gene polymorphisms and risk of IBD, CD and UC.Recently, numerous studies investigated associations between  results -21. The MY09B gene polymorphisms and IBD, CD or UC. We finally identified eight eligible papers [MY09B was showed MY09B gene were investigated, including rs1545620, rs962917, rs1457092, rs2305764 and rs2305767. Genotype distributions of the controls about rs1545620 in one study [P = 0.002). The NOS scores of all included studies ranged from 5 to 7 stars, which suggested they were studies of high methodological quality. Six papers were carried out in Caucasian populations [A total of 47 papers were identified after our initial search. After removing duplicates and screening the titles and abstracts, 37 papers were removed. Therefore, 10 papers were selected for further full text review; two papers , 23 weree papers -21 incluulations , 20, 21,ulations .vs. AA+AC: OR, 0.62; 95% CI, 0.45-0.84, P = 0.002, Figure vs. AA+AC: OR, 0.48; 95% CI, 0.38-0.62, P < 0.001). We did not find rs1545620 was related with UC or CD risk in Caucasian or Asian populations. By exclusion of one Chinese study that did not conform to HWE [vs. AA+AC: OR, 0.53; 95% CI, 0.41-0.69, P < 0.001)  the rs1545620 polymorphism was associated with a decreased risk of IBD; (2)rs2305767 decreased the risk of UC; (3) rs962917 increased the risk of IBD, CD and UC; (4) rs1457092 increased the risk of IBD and UC; (5) rs2305764 was associated with an increased risk of IBD; and (6) stratification analyses indicated that rs1545620 decreased the risk of IBD in Caucasian populations, while rs962917 increased the risk of IBD, CD and UC in Caucasian populations.In this meta-analysis, we evaluated recent studies on the relationships between MYO9B is a candidate gene that is reportedly associated with celiac disease [in vivo, which was associated with increased MYO9B gene expression. Their findings indicated a close link between MYO9B expression and changes in intestinal permeability [MY09B is a candidate susceptibility gene for IBD. disease  and diab disease , 25. A p disease  demonstreability . MYO9B ieability , 28. Theeability , 30. TheMYO9B gene polymorphisms and IBD susceptibility; however, they reported conflicting results. Several studies [MYO9B to be a candidate gene for IBD, while other studies [MY09B gene polymorphisms and the risk of IBD, CD and UC.To date, several studies have assessed associations between  studies , 19, 21  studies , 18, 20 MYO9B gene polymorphisms were not correlated with CD, but were with UC. Van Bodegraven et al. reported that MY09B was more strongly associated with UC than with CD [MY09B gene polymorphisms were not associated with CD in the Canadian/Italian populations [MYO9B may affect susceptibility to UC specifically. With regard to rs962917, only three studies [MY09B in UC are warranted.We determined that rs1545620 was associated with a decreased risk of IBD and rs2305767 was associated with a decreased risk of UC. Moreover, three other SNPs  increased the risk of IBD, CD or UC. It is noteworthy that only rs962917 was related to the risk of CD in this meta-analysis, while the four other SNPs were not. We found that rs1457092 and rs2305767 were associated with the risk of UC. Previous studies have demonstrated genetic differences between CD and UC . Twin co with CD . Furtherulations . It is t studies , 17, 21 MY09B and IBD, CD or UC was not detected in Asian populations. The genetic background of IBD may vary among ethnicities. Previous studies have demonstrated OCTN or CARD15 gene variations to be associated with susceptibility to CD in Caucasian populations [MY09B gene polymorphisms and IBD. Although Hu et al. revealed that MYO9B gene might influence the sub-phenotypic expression of CD, they did not find an association between these MYO9B polymorphisms and intestinal permeability in IBD [MYO9B predispose Caucasians to IBD. However, we cannot definitively state that MYO9B is not related to IBD in Asian patients, because this meta-analysis included only two Chinese studies [MYO9B gene polymorphisms and IBD in Asian populations and other ethnicities.Analyses stratified by ethnicity indicated that rs1545620 decreased the risk of IBD in Caucasian populations. Our data also suggest that rs962917 increased the risk of IBD, CD and UC in Caucasian populations. However, a relationship between ulations , 34, butulations . Two Asiulations  reported studies  with limAmong all included studies, one Chinese study  did not Several potential limitations of this meta-analysis should be taken into consideration. First, one Chinese study did not conform to HWE with respect to rs1545620 polymorphism; however, our data indicated the results of this SNP were trustworthy. Second, the numbers of studies included in the meta-analysis was small, and the sample size of this meta-analysis was not large enough. Third, our results were based on unadjusted estimates, without considering other confounders ; thus, a more precise analysis should be performed, assuming the availability of individual data. Fourth, due to inclusion of only two Asian studies, we could not conduct analyses on rs1457092, rs2305764 or rs2305767 stratified by ethnicity. Future studies that include Asian populations and other ethnic groups are warranted due to ethnic differences in gene polymorphisms. Fifth, the heterogeneity of this meta-analysis was high in some genetic models.MY09B were associated with the risk of IBD, CD or UC. Future large-scale studies in Asian populations and other ethnicities are urgently needed to more accurately characterize associations between MY09B gene polymorphisms and IBD, CD and UC.In conclusion, this meta-analysis indicated that five SNPs within MY09B gene polymorphisms and IBD, CD or UC. The following search terms were used: “inflammatory bowel disease,” “IBD” “ulcerative disease,” “UC,” “Crohn's disease,” “CD,” “MYO9B,” “myosin IXB” and “polymorphisms”. Two independent authors conducted the search. No language or other restrictions were placed on the search. We also performed a manual search of references cited in published articles to identify other initially omitted studies. Any disagreements were resolved by consensus.We performed a comprehensive search in PubMed, Embase, and CNKI databases to identify studies through January 1, 2016 that were related with the P value, and (4) case-control study. Exclusion criteria were: (1) duplication of previous publications; (2) review, editorial, or other non-original studies; (3) studies without detailed genotype data; (4) studies were without control group.Criteria for the inclusion in this analysis were: (1) studies that evaluated the associations between UC or CD or IBD with at least one of the five single nucleotide polymorphisms (SNPs), (2) studied on human beings, (3) study provided sufficient data to calculate the Odds ratios (ORs) and 95% confidence intervals (CIs), and For all eligible studies, the extracted information including: name of first author, publication year, country of origin, ethnicity, numbers of cases (UC and CD) and controls, and polymorphisms. Two authors independently performed the extraction of data and evaluated the study quality based on the Newcastle-Ottawa Scale (NOS) . Total NMY09B gene. P < 0.05 was considered statistically significant. Heterogeneity was evaluated by the Q statistic (significant at P < 0.1) and I2 statistic (where > 50% indicates significant heterogeneity) [2 test. Potential publication bias was investigated with the use of Begger's and Egger's linear regression test [P < 0.05 was considered to indicate statistically significant. The power of this meta-analysis for five SNPs was calculated according to the method recommended by Hedges and Pigott [All statistical analyses were performed using the Stata 11.0 software . Pooled ORs and 95% CIs were calculated to assess the associations between UC or CD or IBD and the five polymorphisms of geneity) . A fixedion test ; P < 0.0d Pigott , with a d Pigott  and pres


Accumulating evidences suggested that tumor necrosis factor alpha inducible protein 3 (TNFAIP3) gene rs10499194, rs13207033 polymorphisms may be associated with the risk of rheumatoid arthritis (RA). However, these studies yielded contradictory findings. To clarify convincing associations, we conducted a comprehensive meta-analysis by searching in PubMed, Embase, and the China Knowledge Resource Integrated Database. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by using fixed-effect or random-effect models. A total of 13 case-control studies for rs10499194 polymorphism and 6 studies for rs13207033 polymorphism were included. Our data indicated that TNFAIP3 gene rs10499194, rs13207033 polymorphisms were associated with the decreased risk of RA. Stratification analyses of ethnicity indicated rs10499194, rs13207033 polymorphisms decreased the risk of RA among Caucasian populations, but not among Asian populations. In conclusion, this meta-analysis indicates that TNFAIP3 gene rs10499194, rs13207033 polymorphisms decrease the risk of RA, especially among Caucasian populations. Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, which is characterized by chronic destructive inflammation in synovial joints. To date, the etiology of RA is poorly understood, but it is believed that complex genetic and environmental factors play important roles in the pathogenesis of RA . PreviouTumor necrosis factor alpha inducible protein 3 (TNFAIP3), a deubiquitinating protein, is reported to play a pivotal role in T cell activation and inflammatory signaling . It can We yielded a total of 251 citations after initial search. 77 citations were removed because of duplicates, and 141 citations were excluded after screening the titles and abstracts. 33 citations were selected for further full text review. 19 citations were excluded due to the following reasons: 9 investigated other polymorphisms; 4 citations did not provide detailed genotyping data; 2 were about juvenile idiopathic arthritis; 3 were reviews; and 1 was not case-control study. We finally identified 14 eligible citations  includinP < 0.001, Figure P = 0.034, Figure P < 0.001, Figure P = 0.044). All included studies conform to Hardy–Weinberg equilibrium (HWE), indicating control subjects were representative of the general population.In the overall analysis, we detected significant association Table  between We assessed sensitivity by omitting each study once at a time in every genetic model for rs10499194 and rs13207033 polymorphisms. The pooled ORs for the effects of these two single nucleotide polymorphisms (SNPs)  and rheumatoid factor (RF). Second, our results were based on unadjusted estimates for confounding factors, which might have affected the final conclusions. Third, we could not assess potential gene-gene and gene-environment interactions because of the lack of relevant data. Fourth, the heterogeneity of this meta-analysis was high in some genetic models. Fifth, the conclusions about rs10499194 polymorphism among Asians should be interpreted with caution due to limited sample size.In conclusion, this meta-analysis indicates that TNFAIP3 gene rs10499194, rs13207033 polymorphisms are associated with the decreased risk of RA, especially among Caucasians. Further studies are necessary to validate whether TNFAIP3 gene rs10499194, rs13207033 polymorphisms contribute to RA susceptibility in other ethnic groups.P value, and (4) case-control study.We systematically searched the PubMed, Embase, and China Knowledge Resource Integrated Database to identify studies through July 26, 2016. The following search terms were used: “tumor necrosis factor alpha inducible protein 3,” “TNFAIP3,” “A20,” “Rheumatoid Arthritis,” “RA,” “polymorphism,” “SNP” and “polymorphisms”. No restrictions were placed on the search. Additional initially omitted studies (such as reference lists of identified studies) have been identified by hand screening. The identified studies conformed to the following criteria: (1) studies that evaluated the association between RA risk and TNFAIP3 gene rs10499194 or rs13207033 polymorphism, (2) studied on human beings, (3) study provided sufficient data to calculate the odds ratios (ORs) and 95% confidence intervals (CIs), and Relevant information was carefully extracted from all eligible studies. The extracted information from all eligible studies including: name of first author, publication year, country of origin, ethnicity, and genotype numbers of cases and controls. Two reviewers independently performed the extraction of data and assessed the study quality based on the NOS . All disP < 0.05 was considered statistically significant. When a Q test indicated P < 0.1 or I2 > 50% indicated heterogeneity across studies, a random-effect model was used. Otherwise, the fixed-effects model was applied [P < 0.05 was considered to indicate statistically significant. The power of this meta-analysis was calculated with a significant value of 0.05 [All statistical analyses were performed using the Stata 11.0 software . ORs and 95%CIs were used to assess the strength of associations between TNFAIP3 gene rs10499194, rs13207033 polymorphisms and RA risk. Stratification analysis was carried out by ethnicity.  applied . Pooled  applied ; P < 0.0 of 0.05 .


Pancreatic cancer is a devastating disease with poor prognosis. The association between vitamin A, retinol and carotenoid intake and the risk of pancreatic cancer occurrence remains controversial, and therefore it is necessary to make a meta-analysis to clarify the association between vitamin A, retinol and carotenoid intake and pancreatic cancer risk. In the present study, PubMed and EMBASE databases were used to identify qualified studies. The association between dietary vitamin A, retinol and carotenoids was estimated by pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs). It was found that there was an inverse correlation between vitamin A, beta-carotene and lycopene intake and the risk of pancreatic cancer , which was more prominent in case-control study subgroup. In conclusion, dietary vitamin A, beta-carotene and lycopene might inversely correlate with pancreatic cancer. Pancreatic cancer is a devastating disease with poor prognosis and the 5-year survival rate remains low at 8%et al. conducted a case–control study to evaluate the association of dietary vitamin D, calcium and retinol and the risk of pancreatic cancer in USA, finding that there was no signification association between themet al. found that vitamin A intake was not related to pancreatic cancer risk when crude fiber intake was adjusted17Vitamin A (retinol) and its derivatives are a group of fat soluble compounds composed of a similar structure which are rich in cod liver oil and play important role in multiple biological processes151617et al., Nkondjock et al. and Zablotska et al. were separated into two studies, respectively1819et al. was also divided into two studiesInitially, 672 articles were identified and 18 eligible studies were included in meta-analysis . The chaThe results pooled by the fixed effect model indicated that there was an inverse association between vitamin A intake and pancreatic cancer risk  . In addiThe meta-analysis based on 11 studies of 9 articles indicated that there was no significant correlation between retinol intake and pancreatic cancer risk . Subgroup analysis by ethnicity and the results showed no significant correlation between retinol intake and the risk of pancreatic cancer . AdditioOverall, there was an inverse correlation between carotene intake and pancreatic cancer risk . After stratification by ethnicity, the association became stronger among Asian population  as compared with that in Caucasian  and the mixed population  . The resAs shown in The results showed no significant association between cryptoxanthin intake and pancreatic cancer risk . After stratification by ethnicity, there was no significant association in Caucasians and the mixed population. Similarly, there was no significant correlation in Caucasians and the mixed population. Subgroup analysis showed no significant correlation between cryptoxanthin intake and pancreatic cancer risk in case-control study and prospective study. The sensitive analysis implied that the result of the meta-analysis was robustness. The forest plot and Egger’s test (P = 0.522) suggested that no significant publication bias in this meta-analysis.Pooled ORs and corresponding 95%CIs indicated that there was no significant correlation between lutein and zeaxanthin intake and pancreatic cancer risk . As it showed in In summary, there was an inverse correlation between vitamin A (including some carotenoids) intake and pancreatic cancer risk, but no significant correlation was observed between retinol intake and pancreatic cancer risk. All the results were summarized in This meta-analysis included 18 articles focusing on the correlation between vitamin A, retinol and carotenoid intake and pancreatic cancer risk. The result showed that dietary vitamin A, carotene, beta-carotene and lycopene were inversely correlated with the risk of pancreatic cancer risk. However, retinol, alpha-carotene, cryptoxanthin, lutein and zeaxanthin intake had no relationship with pancreatic cancer risk.Vitamin A is a necessity for cell growth and differentiation of epithelial tissues and must be obtained from diets in the human body. Provitamin A compounds, such as beta-carotene can transform into vitamin A, which is an essential molecule entailing multiple developmental pathways and influencing cell proliferation and differentiation in a variety of cell types2324Other carotenoids such as lycopene and zeaxanthin that cannot convert into vitamin A may act as antioxidants against cancer initiation and progression. Lycopene has been proved to be a potent inhibitor for cell proliferation and growth in some cancer cells, such as endometrial cancer, breast cancer and lung cancer27et al. conducted a meta-analysis to assess the relationship between dietary vitamin C and pancreatic cancer risk and found that a higher vitamin C intake was inversely correlated with pancreatic cancer risk1517323334Several meta-analyses or pooled analyses have investigated the association between the intake of other vitamins and pancreatic cancer risk. Fan et al. conducted a meta-analysis and found that beta-carotene and alpha-carotene were inversely correlated with risk of gastric cancer1517193233383940314243The association between carotenoid intake and cancer risk had been investigated in many cancer types. Zhou Between-study heterogeneity is common in meta-analysisAlthough the results obtained in our meta-analysis are statistically significant as a whole, several limitations should be noted in interpreting our study. First, most included studies in our meta-analysis were case-control studies, in which recall bias may be unavoidable. Both case-control and cohort study are observational study, they require fewer resources but provide less evidence compared with randomized controlled trial (RCT). However, given the extremely low morbidity of pancreatic cancer, there is too difficult to conduct RCT on the association between vitamin A, retinol and carotenoid intake and the risk of pancreatic cancer. Second, some confounding factors such as eating habits and residual confounding cannot be measured, which may affect the stability and credibility of our meta-analysis. Third, the individual sample sizes for each case in most studies included in this meta-analysis were relatively small and these studies were conducted in different populations whose heredity might be different. Finally, some pancreatic cancer cases may be familial heredityIn conclusion, the results of our meta-analysis indicate that high-level vitamin A, carotene, beta-carotene and lycopene intake might be the potential factors related to low pancreatic cancer risk. However, due to the limitations of the present meta-analysis mentioned above, it should be prudent to make recommendations based on the results of the present meta-analysis.th, 2015 by using the following key words “Vitamin A or Vitamin or diet or dietary or retinol or carotenoids or carotene or cryptoxanthin or lycopene or lutein or zeaxanthin” and “pancreatic” and “cancer or carcinoma or neoplasm or tumor or adenocarcinoma”. Additionally, some potential studies were identified via secondary searches which were conducted by searching reference lists of selected literatures.PubMed and EMBASE databases were used to identify observational studies that reported the association between vitamin A, retinol and carotenoid intake and the risk of PANCREATIC CANCER up to December 30The inclusion criteria were: (1) observational studies including case-control and cohort study design; (2) studies reporting the association between exposure factors including vitamin A, retinol and carotenoids and the risk of pancreatic cancer; (3) studies published in English or Chinese; (4) Providing the odds ratio (OR)  data and the corresponding 95% corresponding interval (CI) for the highest vs. the lowest level of vitamin A intake or retinol intake or other carotenoid intake. The exclusion criteria were: (1) reviews, meta-analyses, case reports, editorials or human-uncorrelated experiments; (2) duplicated study ; (3) studies not reporting OR and 95%CI or lacking sufficient data to calculate OR(or RR and HR) and 95%CI.The process of data extraction was conducted by two authors independently with a standardized form based on the inclusion and exclusion criteria mentioned above. Any divergence was resolved by rechecking until consensus was reached. The following information was collected: the last name of the first author, publication year, country, ethnicity, study design, number of cases and controls or total sample size, carotenoid types, OR, the corresponding 95% CI from the most fully adjusted model for the highest vs. the lowest vitamin A intake, and the factors of adjustment for covariates.Newcastle-Ottawa-Scale (NOS) was applied in quality assessmentI2. When I2 > 50%, the random effect model was suggested to calculate the pooled OR and 95%CI. Otherwise, the fixed effect model was applied. Furthermore, sensitivity analysis was conducted by omitting each study once a time. We also assessed publication bias via funnel plots and Egger’s testIf the outcome under study is rare in all populations and subgroups under review, one can generally ignore the distinctions between the various measures of relative riskHow to cite this article: Huang, X. et al. Association between vitamin A, retinol and carotenoid intake and pancreatic cancer risk: Evidence from epidemiologic studies. Sci. Rep.6, 38936; doi: 10.1038/srep38936 (2016).Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


DRD2/ANKK1 gene Taq1A polymorphism and smoking cessation, the results remain controversial. The primary objective of the present study was to determine whether this variant indeed has any effect on smoking cessation. The A1-dominant model that considers A1/* (*=A1 or A2) and A2/A2 as two genotypes and compares their frequencies in current and former smokers was applied. A total of 22 studies with 11 075 subjects were included in the meta-analyses. Considering the potential influence of between-study heterogeneity, we conducted stratified meta-analyses with the Comprehensive Meta-Analysis statistical software (version 2.0). Results based on either cross-sectional or longitudinal studies consistently showed a statistically significant association between Taq1A A1/* genotypes and smoking cessation. Further, a more significant association of the variant with smoking cessation was detected when both types of studies were combined. However, there was marginal evidence of heterogeneity among studies (I2=33.9% P=0.06). By excluding other ethnicities and subjects with cancer, the meta-analysis on the basis of 9487 Caucasians demonstrated that Taq1A A1/* genotypes indeed were significantly associated with smoking cessation under both the fixed- and random-effects models . No evidence of between-study heterogeneity or publication bias was observed. Thus, we conclude that the polymorphism of Taq1A has an important role in the process of abstaining from smoking, and smokers carrying A2/A2 genotype have a higher likelihood of smoking cessation than those who carry A1/A1 or A1/A2.Although a number of studies have analyzed the relation between the  A great number of studies have focused on determining whether variants in genes with a dopaminergic function could contribute to the heritable variation of smoking behaviors. This reward system consists of three parts: dopamine receptors, dopamine transporters and enzyme targets, which jointly modulate the concentrations of dopamine in synaptic clefts. Because of increasing synaptic dopamine concentrations to a higher level than those stimulated by natural rewards such as sexual intercourse and food, nicotine from cigarette smoke is considered a partial moderating factor of smoking maintenance, and variants in those genes linked with increasing the concentrations of synaptic dopamine appear to be more likely to be involved in smoking cessation.DRD2, located on chromosome 11q22–q23, has received much attention.9 Many studies16 have reported that a growing number of variants in DRD2 are significantly associated with smoking behaviors. In particular, the Taq1A polymorphism (dbSNP rs1800497), located ~9.5 kb downstream from DRD2 and in exon 8 of ANKK1, has been investigated extensively. Since Noble et al.17 first showed that there was a significantly higher prevalence of Taq1A A1 allele among current smokers (P=0.024) and former smokers (P=0.044) than among nonsmokers in the Caucasian population, many genetic association studies27 were conducted to elucidate the association between the polymorphism of Taq1A and smoking-related phenotypes, including cessation. However, the results remain ambiguous. For example, two meta-analyses29 showed no evidence of association between Taq1A polymorphism and smoking behaviors, whereas other two meta-analyses31 showed significant associations of Taq1A polymorphism with smoking behaviors. In addition, there exists heterogeneity among the findings of reported studies.Of these genes, in vivo and in vitro studies35 have documented that the minor A1 allele  of the Taq1A polymorphism is correlated with regulating the density and availability of dopamine D2 receptor, indicating that the variant potentially involves tailoring of the concentrations of synaptic dopamine. Therefore, it is rational to assume that the Taq1A polymorphism has an important part in regulating smoking cessation. A growing body of pharmacogenetic evidence39 has suggested an association of Taq1A polymorphism with the pharmacotherapy of smoking cessation, although a few longitudinal treatment studies41 have failed to reveal such an association. Many moderating factors could be causing these inconsistent results, such as gene × sex42 and DRD2 × SLC6A3 interactions.43Both 44 regarding the association of Taq1A polymorphism with smoking cessation. On the basis of five cross-sectional studies with relatively small samples , the first reported meta-analysis by Munafo et al.28 found no evidence of an association between the variant and smoking cessation. Then Ohmoto et al.31 performed an independent meta-analysis by pooling six cross-sectional studies and one longitudinal treatment study, of which only the placebo arm was employed (N=4249). The authors demonstrated that smokers with one or more A1 alleles have more difficulty of quitting smoking than do those carrying homozygous A2 alleles in both the overall population (pooled odds ratio (OR) 1.19; 95% confidence interval (CI) 1.05–1.35; P=0.008) and the Caucasian population . Very recently, a meta-analysis by Choi and Shin44 integrating nine longitudinal treatment studies of which the placebo arms were excluded (N=2851), showed that there was no significant association between DRD2 Taq1A polymorphism and smoking cessation outcomes. Because no meta-analysis was conducted combining the effects from both longitudinal treatment and cross-sectional studies, and several related studies were recently reported, it is important to conduct an updated meta-analysis for the effect of Taq1A polymorphism on smoking cessation. Thus, we performed a stratified meta-analysis by considering the influence of the underlying sources of heterogeneity such as method variation, ancestral variation and sampling variation.To date, there have been three meta-analysesDRD2/ANKK1 Taq1A polymorphism with smoking by interrogating the electronic database of PubMed. From the first date available in the database up to 17 May 2015, the search was performed using the following key terms: ‘dopamine D2 receptor,' ‘DRD2,' ‘smoking,' ‘nicotine,' ‘cigarette' and ‘tobacco.' Electronic abstracts were examined for potentially relevant articles in accordance with the standard inclusion and exclusion criteria suggested by Moher et al.45 Duplications were discarded. Once studies met the criteria for selection, the references were hand-checked for underlying additional studies. Articles that reported previously published data were excluded.We searched the reported studies on the association of et al.,36 which were the same data used by Johnstone et al.,37 23 eligible studies, consisting of nine cross-sectional surveys,47 one longitudinal no-treatment study48 and 13 longitudinal treatment studies55 satisfied the inclusion criteria for this meta-analysis. As described in many previous studies,57 we used a comparison of current smokers (non-abstinent group) with former smokers (abstinent group) to define the phenotype of smoking cessation for all acceptable studies. For each study, the following data were extracted by two authors (YM and MW) using standardized forms: authors and year of publication, language (English or other), country of origin, type of study, ancestry of sample, sample size, sex ratio, statement of Hardy–Weinberg equilibrium, diagnostic criteria, classification of smoking status and the number of participants having different smoking statuses categorized by the Taq1A genotype .47 and 14 longitudinal studies,55 which were published between 1994 and 2014. A total of 11 151 participants were extracted from these papers, which included sample sizes from 76 to 2123  in Caucasians and from 44.8 to 70.1% (mean=60.9%) in East Asians. In this meta-analysis, a total of 4411 participants were identified with A1/* genotypes with a frequency of 39.6%, which was in conformity with the frequencies in the Caucasian population. In addition, there was a wide distribution of cessation rates between 9.6 and 66.9%. The cessation rates of the cross-sectional studies and partial longitudinal studies, in which the smoking status was verified at end of treatment, ranged from 21.9 to 66.9%, whereas that of the longitudinal studies checked at 6- or 12-month follow-up were relatively lower (9.6–33.1%).Through this stringent search strategy, we selected 23 eligible studies consisting of nine cross-sectional surveys to 2123 . For theTaq1A A1/* genotypes on smoking cessation by combining 10 data sets extracted from nine cross-sectional studies in that the data set of the study by Wu et al.21 was divided into two parts according to ancestral origin. The pooled OR was 1.12 (P=0.07) with 95% CI ranging from 0.99 to 1.27 under the fixed-effects model and 1.03 (P=0.84) with 95% CI from 0.81 to 1.30 under the random-effects model . By taking into account the variation of ethnicity, we repeated the meta-analysis on the basis of predominant Caucasian ancestry, which revealed a significant association of Taq1A polymorphism with smoking cessation under the fixed-effects model . The forest plot is presented in Because only one study, reported by Gordiev ribution , it is rP=0.003) with 95% CI of 1.06 and 1.36. In the random-effects model, the OR was 1.20 (P=0.007) with 95% CI of 1.05 and 1.37. There was no evidence of significant heterogeneity among studies (I2=11.0% P=0.33). For this part of the analysis, the results from the fixed-effects model seem to be more encouraging, indicating a statistically significant association of Taq1A A1/* genotypes with smoking cessation  and the random-effects  models. The P-value of the Q-statistical test was 0.39, and the value of the I2 statistical test was 6.1%, indicating no evidence of between-study heterogeneity. These data are shown in By pooling all the longitudinal studies, the OR in the fixed-effects model was 1.20  with 95% CI of 1.06 and 1.27 under the fixed-effects model (I2=33.9% P=0.055), but when repeating the meta-analysis under the random-effects model, we found that evidence for association remained significant .Considering there were no significant differences in the pooled effects between the cross-sectional surveys and the longitudinal studies, we combined these studies to conduct a meta-analysis, as previously reported.ts model . There w21 With regard to East Asians, there was no evidence of significant association of Taq1A A1/* genotypes with smoking cessation . The forest plot is presented in I2=23.0% P=0.18). When we performed the meta-analysis under the random-effects model, the pooled OR was 1.16 (P=0.009) with 95% CI of 1.04 and 1.30. Again, after excluding the study of Gordiev et al.,23 the I2 value is reduced to 0, and the P-value of the Q-test increased to 0.63, indicating that the residual between-study heterogeneity has been eliminated. The results showed a more significant effect of Taq1A A1/* genotypes on smoking cessation under the fixed- and random-effects models , indicating that individuals with the homozygous Taq1A A2/A2 genotype are more likely to be successful in abstinence from cigarette smoking than those with A1/A1 or A1/A2 genotypes.In this study, we observed an effect of DRD2) is one of the important components of the dopaminergic reward pathway. Many studies have concentrated on determining whether variants in DRD2 confer susceptibility to addictive disorders including smoking-related phenotypes and other psychiatric disorders. Multiple lines of evidence16 have demonstrated that numerous variants in DRD2 are significantly associated with smoking behaviors. The polymorphism of rs1800497, which historically has been referred to as ‘DRD2 Taq1A', although it is located in ANKK1, was widely investigated in many genetic association studies27 for smoking behaviors, including cessation. Furthermore, the Taq1A A1 allele has been associated with regulation of the functions of the dopamine D2 receptor by reducing the densities and binding affinity,35 which may be one of the underlying molecular mechanisms of the association of the Taq1A A2/A2 genotype with the higher likelihood of abstaining from smoking. Nevertheless, there is a question remaining to be addressed: how a variant in Taq1A residing ~9.5 kb downstream from DRD2 could influence the expression of DRD2. One speculative hypothesis is that the variant acts as a proxy marker in linkage disequilibrium (LD) with causative variant(s) within DRD2. Zhang et al.60 documented that Taq1A was in strong LD with rs2283265 and rs1076560 of DRD2 (D′=0.86). Those two intronic single-nucleotide polymorphisms have been significantly associated with addictions,66 schizophrenia71 and reduced density of D2S relative to D2L and D2 receptors.60Dopamine receptors consist of two subfamilies with different functions: D1-like, including D1 and D5, and D2-like, including D2, D3 and D4. In particular, the dopamine D2 receptor  in ANKK1. For example, Gelernter et al.10 reported that Taq1A is in complete LD with rs11604671 (D′=1.0) and in moderate LD with rs4938015 (D′=0.73), which are two functional variants in ANKK1. Given that the function of ANKK1 in the dopaminergic reward pathway is still unclear, more related functional studies are warranted. Meanwhile, as next-generation sequencing technologies become available, gene-based deep-sequencing analysis of the DRD2/ANKK1 gene cluster can be used to reveal more novel functional variants, which may be in strong LD with the Taq1A polymorphism, conferring susceptibility to smoking cessation.Another possible mechanism is that the 23 and performed another meta-analysis. The residual heterogeneity among studies was eliminated, indicating that the findings of our meta-analysis for the Caucasian population were much more reliable. Unfortunately, the current study had an insufficient number of studies to incorporate East Asian subjects in the estimate of pooled effect. In addition, it is worth noting that there were several whole-genome-wide association studies75 where the Taq1A polymorphism was not revealed as a variant significantly associated with smoking cessation at the genome-wide significant level. To some extents, this is not surprising to us at all as so far only limited loci were identified by genome-wide association studies even in a study with a sample size of >140 000.75 Many factors might have contributed to this phenomenon; for example, inconsistent definition of smoking cessation phenotype and high heterogeneity among different studies, and very conservative threshold for significance with stringent Bonferroni correction.To avoid the influence of underlying heterogeneity among studies, several stepwise stratified analyses were carried out in our meta-analyses. We first implemented two subgroup meta-analyses by two methods before combining the two types of studies. There was no evidence that the observed effect for the cross-sectional studies and the longitudinal studies were heterogeneous, providing persuasive evidence for the robustness of the finding of our meta-analysis of combined studies. In light of the differences in the frequencies of the A1/* genotype among different ethnic groups, we speculated that the influence of ethnicity might be attributable to the detected heterogeneity among studies. After excluding the subjects of East Asian and other non-Caucasian origins, the between-study heterogeneity was obviously reduced even though not erased. The results of the meta-analysis showed a more significant association in the Caucasian population. Further, we excluded the study of cancer patientsTaq1A A1/* genotypes with smoking cessation was revealed, the results of our meta-analysis should be interpreted with caution in view of the following potential limitations. First, although reconciling the phenotypes of the chosen studies to the degree we could, the longitudinal treatment studies had different time frames for abstinence assessment, which might influence the observed effect of Taq1A polymorphism on smoking cessation. Furthermore, various medicines were used in these treatments for smoking abstinence interventions, which might also affect the detected association of the variant with smoking cessation, even though this study was concentrated on the main effect of DRD2 genotypes on smoking cessation. Second, there were different sex ratios and mean ages of participants among these studies, which may be contributable to limitations, as suggested by many previous studies.76 Finally, because there are an insufficient number of studies on other polymorphisms, we could not examine the gene-by-gene interactions by which the pathogenesis of complex addictive disorders, including cessation, could be influenced. For example, Lerman et al.38 indicated that there was a significant statistical interaction of SLC6A3 × DRD2 with smoking cessation at the end of treatment, such that smokers with SLC6A3 9-repeat and DRD2 A2A2 genotypes were more likely to abstain from cigarette smoking than were those who carry SLC6A3 non-9-repeat and DRD2 A2A2 genotypes. Further, Swan et al.43 consistently reported that subjects with both A1/* and non-9-repeat genotypes were less likely to be abstinent from smoking at 12-month follow-up. Recently, a meta-analysis57 by our group documented that a significant effect of SLC6A3 3′-UTR VNTR 9-repeat genotypes on smoking cessation in Caucasians, with an estimated effect of a 9-repeat allele being a 17% increase in the likelihood of abstinence. We thus postulate that DRD2 Taq1A A2/A2 and SLC6A3 9/* genotypes could contribute interactively to the process of quitting smoking.Although a statistically significant association of DRD2 Taq1A polymorphism and smoking cessation in a large Caucasian population. In comparison with smokers carrying one or more A1 alleles, smokers with homozygous A2 alleles are more likely to remain abstinent from cigarette smoking. Our results provide supportive evidence for further investigation of personalized medicine for smoking cessation according to individual genotypes. However, research on this problem remains in its infancy, so more well-designed genetic association, pharmacogenetic and molecular functional studies are warranted to reveal the function of ANKK1 in the dopaminergic reward system and the molecular mechanism of Taq1A polymorphism for the etiology of smoking cessation; examine the association of other variants located in DRD2/ANKK1, which are in LD with the polymorphism of Taq1A, with cessation; identify more novel causative variants associated with cessation; and explore the underlying molecular mechanism of their function on tailoring intervention in nicotine dependence.In summary, the results of the current meta-analyses reveal a statistically significant association between the


Statistical significance of rs6265 was lost when one single study was excluded from the analysis , suggesting lack of robustness of pooled estimates. When stratified by migraine type, a similar trend of association was detected with both MA and MO, but a statistically significant association of rs6265 was reached only with the MA subtype in the dominant model . The present meta-analysis supports that BDNF rs6265 may act as a genetic susceptibility factor for migraine. Nevertheless, large-scale studies are required to confirm our findings and to assess potential modifiers of the relationship between rs6265 and migraine.Inconclusive results have been reported in studies investigating the association between the brain-derived neurotrophic factor (BDNF) rs6265 polymorphism and migraine. In the present study, we conducted a systematic review and meta-analysis on the published data in order to quantitatively estimate the relationship between rs6265 and migraine susceptibility. A comprehensive search was performed through PubMed, Web of Knowledge, and Cochrane databases up to October 2016. The pooled odds ratio (OR) with the corresponding 95% confidence interval (CI) was calculated to estimate the strength of the association with rs6265 under an additive, dominant, or recessive model of inheritance. A total of five studies including 1,442 cases and 1,880 controls were identified for the meta-analysis. The pooled data showed an increased risk of migraine for the allelic (OR: 1.17, 95% CI: 1.03–1.34,  Migraine is a disabling neurovascular disease affecting more than 10% of worldwide population, with a female-to-male prevalence ratio of about 3:1 . The morThe brain-derived neurotrophic factor (BDNF), a neurotrophin involved in synaptic plasticity and survival of neurons, has been reported to play also a role in the modulation of pain signaling and in central sensitization , 8. The The BDNF gene encodes for a precursor peptide (pre-pro-BDNF), which is subsequently cleaved to generate the precursor of BDNF (proBDNF) and mature BDNF . Each ofCandidate gene association studies have been criticized for a number of weaknesses including insufficient sample size of most studies or insufficient replication of the results . As thesvia email when relevant data were not extractable from the published manuscript. One of them (The protocol for this review was published in the PROSPERO database of prospectively registered systematic reviews (registration ID: CRD42016049038) . PubMed, of them  generoushttp://ihg.gsf.de/cgi-bin/hw/hwa1.pl). The quality of case–control studies was evaluated using a risk-of-bias score for genetic association studies, as adopted in a previous meta-analysis  and controls, sample characteristics , and detection method. Deviation of rs6265 from the HWE was calculated using the Pearson’s goodness-of-fit chi-square test implemented in the online Finetti’s program (available at: 2–based Cochran’s Q statistic (significant for p < 0.10) (I2 index (range 0–100%) was also reported, which quantifies heterogeneity irrespective of the number of included studies (http://www.cebm.brown.edu/openmeta/) and ProMeta software Version 2 , and significance of pooled estimates was set at p < 0.05. Publication bias was evaluated by the Egger’s test .For each study, the OR with the corresponding 95% confidence interval (CI) was calculated to estimate the strength of the association between BDNF rs6265 gene polymorphism and migraine. OR estimates were combined based on the allele (A vs G), dominant , and recessive  genetic contrast of rs6265 by using the random-effects (DerSimonian–Laird method) model, which takes into account any difference among studies even if there is no statistical heterogeneity . In case < 0.10) . The I2  studies . Leave-or’s test  using thA total of 59 studies were identified through a search of PubMed, Web of Knowledge, and Cochrane databases. After exclusion of 54 hits for not meeting the inclusion criteria, five studies with 1,442 cases and 1,880 controls were, therefore, included in the final meta-analysis –21, 25. p = 0.60, I2 = 0%; dominant model: p = 0.63, I2 = 0%; recessive model: p = 0.95, I2 = 0%). The pooled analysis showed significant association in the allelic . Nevertheless, given the low power of the Egger’s test to detect funnel plot asymmetry, especially when limited number of studies are included in the meta-analysis, small-study effects, or publication bias cannot be excluded.A summary of meta-analyses on the association between rs6265 and migraine risk is displayed in Table p = 0.054; allelic OR: 1.14, 95% CI: 0.99–1.31, p = 0.067). To assess the potential effects of specific study characteristics on the association between rs6265 and migraine susceptibility, we pooled the OR and 95% CI from the subgroups of migraine type and study quality. When stratified by migraine type, a similar trend of association was detected with both MA and MO, but statistically significant association of rs6265 was reached only with the MA subtype in the dominant model . When stratified by study quality, statistical significance was reached among studies with higher quality .To evaluate the robustness of overall pooled estimates, we performed a leave-one-out sensitivity analysis by iteratively removing one study at a time and recalculating the summary OR. The results showed that statistical significance of the allelic Figure A or the The BDNF rs6265 SNP has been associated with an altered intracellular packaging of the precursor of BDNF and a decreased production of mature BDNF , which cIn the present study, we conducted a systematic review and meta-analysis of published data to quantitatively estimate the impact of BDNF rs6265 on migraine susceptibility. The pooled results have indicated that BDNF rs6265 confers an increased risk for migraine, reaching significant level under the allelic or the dominant model of inheritance. In addition, subgroup analysis based on migraine type shows a statistical significant association with migraine with aura (MA) under the dominant model of rs6265. In this regard, it is noteworthy that the BDNF gene is differentially expressed in the rat after cortical spreading depression , the putOur findings suggest that reduced BDNF protein levels in the brain, which are to be expected in carriers of the Met allele of BDNF Val66Met polymorphism (rs6265A), may increase the likelihood of migraine. Intriguingly, positron emission tomography scanning in healthy subjects showed a lower 5-HT1A receptor binding potential in 13 brain regions of interest among carriers of rs6265A allele in comparison with non-carriers , a resulThe limitations of this meta-analysis should not be ignored when interpreting the results. First, the pooled analysis was based on five case–control studies, with a limited numerosity of subjects, who also were mostly Caucasian. In addition, results of leave-one-out sensitivity meta-analysis indicated that the statistical significance of rs6265 was altered when one single study was omitted, thus indicating a lack of robustness of pooled estimates. Thus, caution is needed when interpreting overall and subgroup analyses based on migraine type. Further large studies including populations of different ethnic origin are, therefore, required to provide more conclusive evidence of an association between rs6265 and migraine. Second, migraine is a female-predominant multifactorial disease influenced by complex gene–gene or gene–environment interactions. However, stratified analyses by gender and environmental exposures were precluded owing to insufficient data. Third, the pooled estimates were based on unadjusted data, which might have affected the accuracy of the results. In the future, a collaborative meta-analysis may provide a more precise evaluation of the association between rs6265 and migraine.In conclusion, our meta-analysis based on five case–control association studies suggested that rs6265 polymorphism of the BDNF gene may confer an increased susceptibility to migraine. However, the impact of gender and ethnicity as well as the investigation of gene-environment interactions should be taken into consideration in future large-scale studies to confirm our findings and to better understand the relationship between the BDNF rs6265 polymorphism and migraine susceptibility.ST performed the critical analysis of the literature and prepared the manuscript. SC has collected and evaluated the data from the literature. She has collaborated to the critical analysis of existing evidence and has collaborated to the preparation of the manuscript. MV has collaborated to the critical analysis of the data and to the preparation of the manuscript. MV has collaborated to the critical analysis of the data and to the revision of the manuscript. CT contributed with the idea of the review, analysis of data, and revision of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.