There are still inconsistent conclusions about the association of prenatal alcohol drinking with congenital heart defects (CHDs). We conducted this meta-analysis to investigate the association between prenatal alcohol exposure and the risk of overall CHDs and the CHDs subtypes.2 statistic.Case-control and cohort studies published before March 2015 were searched through PubMed and Embase. Two authors independently extracted data and scored the study quality according to the Newcastle-0ttawa Scale. The pooled ORs and 95%CI were estimated using the random-effects model and heterogeneity was assessed by the Q test and IA total of 20 studies were finally included. The results provided no evidence of the association between prenatal alcohol exposure and the risk of overall CHDs , ventricular septal defects (VSDs) , or atrial septal defects (ASDs) . However, prenatal alcohol drinking was marginally significantly associated with conotruncal defects (CTDs)  and statistically significantly associated with d-Transposition of the Great Arteries (dTGA) . Moreover, both prenatal heavy drinking and binge drinking have a strong association with overall CHDs , and prenatal moderate drinking has a modest association with CTDs  and dTGA .In conclusion, the results suggested that prenatal alcohol exposure was not associated with overall CHDs or some subtypes, whereas marginally significant association was found for CTDs and statistically significant association was found for dTGA. Further prospective studies with large population and better designs are needed to explore the association of prenatal alcohol exposure with CHDs including the subtypes in specific groups. Congenital heart defects (CHDs) refer to the structural anomalies of the heart and great vessels that are present at birth and can disrupt the normal flow of blood through the heart or vessels near it. As the most prevalent congenital abnormalities in the world, CHDs account for nearly thirty percent of total major congenital anomalies, with anPrenatal alcohol exposure can exert a wide range of adverse effects on the developing fetus, such as craniofacial abnormalities, growth deficiencies, central nervous systems dysfunctions, and neurobehavioral disabilities, collectively known as fetal alcohol spectrum disorders (FASD). Animal studies have indicated that maternal exposure to alcohol during the gestational period increases the incidence of heart anomalies in the offspring , 8. AccoAlthough the effect of maternal alcohol consumption on CHDs has been explored for decades, there are still inconsistent conclusions about the association of maternal alcohol exposure with CHDs, including the CHDs subtypes. To our knowledge, there has been no comprehensive meta-analysis to explore the relationship between prenatal alcohol exposure and CHDs. Two previous systematic reviews written by Henderson et al. , 14 trieS1 Checklist). The protocol of this meta-analysis was not registered anywhere. We searched PubMed and Embase to identify all relevant case-control and cohort studies published as original articles in English up to March 2015. The following medical subject headings and text words were used to identify relevant articles:  AND . We also scanned the reference lists of the identified articles to find additional publications of interest.We performed the meta-analysis and reported the results in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines  or odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) could be directly extracted or calculated from the available data;original study without duplicated data.Two reviewers independently scanned all the titles and abstracts of the retrieved studies to exclude distinctly irrelevant ones, and then they independently assessed the full texts to determine whether the remaining articles met the eligibility criteria. Discrepancies between the two reviewers during each stage were settled by discussion with the third reviewer. A published study was included if it met the following inclusion criteria:We didn’t include studies where mothers of interest were diagnosed with CHDs, diabetes, or other abnormal conditions. We also exclude studies where the infants of interest were specifically referred to those with Down syndrome. Animal studies, letters, editorials, conference abstracts, reviews, or comments were not included. If there were multiple articles with the same or overlapped data, only the study with the most comprehensive information, such as the longest study period or the most overall CHD subtypes, was selected.Data extraction and study quality assessment were performed independently by two reviewers through a piloted form, and any disagreement was resolved by discussion with the third reviewer. The following information were recorded from the eligible studies: first author’s surname, publication year, study period, study type , study country, sample size, ascertainment of alcohol exposure and CHDs , timing of drinking, adjusted or matched confounders, risk estimates and corresponding 95% CIs. The methodological quality of the included studies was scored according to the Newcastle-0ttawa Quality Assessment Scale (NOS). This sc2 statistic[P<0.10 or I2 >50% was suggestive of statistically significant heterogeneity. Moreover, we performed subgroup analyses according to geographical area , study type, timing of drinking, publication year , and sample size . We carried out sensitivity analysis by reanalyzing the summary estimates after removal of each study in turn. We also conducted sensitivity analysis by restricting the analysis to high-quality studies. Publication bias was assessed by funnel plot and Egger’s regression asymmetry test[P<0.05 was considered to be statistically significant. Analyses were conducted using STATA software .The measure of interest was OR. We used the adjusted OR that was controlled for potential confounders in the greatest degree whenever available; otherwise, we utilized the unadjusted OR or computed it from the exposure distributions given in the studies. A random-effects model was applied to estimate the pooled ORs and 95%CI because statistic. P<0.10 etry test when adeFig 1. From the 4853 citations retrieved in the electronic databases, 104 had the potential to be eligible after the initial screening based on titles or abstracts. Of these, 86 articles were excluded after further reviewing the full texts, leaving 18 studies for inclusion. Additionally, two eligible articles were identified from the reference lists. Thus, a total of 20 studies were found to meet all the inclusion criteria for final inclusion in the meta-analysis.The flow chart of literature search and study selection is shown in S1 Table. The 20 studies were published between 1987 and 2013 and the study period ranged from 1974 to 2010, with a total population of 310,919. Of these studies, four were cohort studies [The characteristics of the included studies are shown in  studies , 12 were studies –35, and  studies –39. Nine studies –27 conduFig 2). No significant heterogeneity among studies was found . Subgroup analyses stratified by geographical area, study type, timing of drinking, or publication year yielded no significant association (Table 1). However, a borderline significantly higher risk of overall CHDs associated with prenatal alcohol intake was found in studies with sample size larger than 1,000 .The relationship between prenatal alcohol exposure and overall CHDs was investigated in 8 studies, with a total number of 3,749 cases and 122,200 controls. The pooled result suggested that prenatal alcohol drinking seemed to slightly increase overall CHDs risk, but the confidence interval included unity   . Subgroup analysis by geographical area showed the same nonsignificant association in North America  and Europe , while one study conducted in Australia reported an increased risk of VSD . Moreover, subgroup analysis indicated a borderline significant association among studies that explored maternal alcohol drinking during pregnancy  and a significant association among studies published in 2000 later . In addition, heterogeneity became nonsignificant among subgroups based on geographical area, timing of drinking, and publication year (Table 2).The association between prenatal alcohol exposure and ventricular septal defects (VSDs) was assessed in seven studies, with a total number of 1,719 cases and 198,285 controls. No significant difference in VSD risk was found between mothers who drank before or during pregnancy and those who did not drink , and significant heterogeneity was observed , and no significant heterogeneity was found . One cohort study conducted in Australia contributed data to the association of maternal alcohol use during pregnancy with CTDs risk, and reported a borderline significant association . Furthermore, subgroup analyses showed that prenatal alcohol consumption was associated with an increased risk of CTDs among studies published after 2000  and studies with large sample size (>1000)  (S2 Table).The association of prenatal alcohol intake with conotruncal defects (CTDs) was examined in five studies, with a total number of 716 cases and 83,825 controls. As presented in S1 Fig). However, mothers who drank in pregnancy had 1.64 times more likely to have a newborn with d-Transposition of the Great Arteries (dTGA)  . No heterogeneity across studies was detected for the two associations .In addition, three studies explored the effects of prenatal alcohol exposure on the two subtypes of CTDs, Tetralogy of Fallot (TOF) and d-Transposition of the Great Arteries (dTGA). The pooled estimate showed no significant risk of TOF associated with prenatal alcohol use   . When the analysis was restricted to the studies that investigated the association during the first trimester or were published before 2000, the result showed a significant association . Significant result was also found in the study conducted in Australia , the population-based case-control study , and studies with small sample size (≤1000)  (S3 Table). In addition, heterogeneity became negligible among studies with small and large sample size (I2 = 0 for both subgroups).The association between maternal alcohol exposure and atrial septal defects (ASDs) was evaluated in four studies, with a total number of 349 cases and 191,576 controls. The summarized result suggested that maternal alcohol exposure was not significantly related with ASDs risk , and the heterogeneity among studies was significant  . Two publications by Tikkanen et al. , 27 repoP = 0.85, I2 = 0%) after deletion of the study by Adams et al.[P = 0.95, I2 = 0%) after removal of the study by Standberg-Larser et al. [Sensitivity analyses by removing of the poor-quality studies showed that the results did not change for the relationship between prenatal alcohol exposure and overall CHDs , VSDs , CTDs , or ASDs . Moreover, the association for overall CHDs or VSDs did not materially alter after exclusion of each study in turn. However, the association for CTDs turned out to be significant  and the heterogeneity was greatly decreased , VSDs (P = 0.12), CTDs (P = 0.68), TOF (P = 0.21), or ASDs (P = 0.76). Fig 5 shows the funnel plot for the association between prenatal alcohol exposure and overall CHDs risk.According to Egger’s test, no publication bias was detected for the associations of prenatal alcohol consumption with overall CHDs . However, no significant result was detected for the effects of prenatal binge drinking on the CHD subtypes (S4 Table).The effect of prenatal binge drinking on CHDs risk was assessed in a total of seven studies. In comparison with none drinking, prenatal binge drinking correlated with a 1.49 times increase in overall CHDs risk  without significant heterogeneity , adequate control for important confounders, are needed to explore the actual relationship between prenatal alcohol drinking and CHDs, especially with regard to the CHDs subtypes. Moreover, more studies, particularly in the eastern countries, are still needed to investigate the association of prenatal alcohol exposure with CHDs including the subtypes in specific groups.S1 PRISMA Checklist(DOC)Click here for additional data file.S1 Fig(TIF)Click here for additional data file.S2 Fig(TIF)Click here for additional data file.S1 Table(DOC)Click here for additional data file.S2 Table(DOC)Click here for additional data file.S3 Table(DOC)Click here for additional data file.S4 Table(DOC)Click here for additional data file.


P = 0.014) was observed among individuals with hypertension. There was statistically significant heterogeneity among included studies . No obvious evidence of significant publication bias was detected by either Begg’s test (P = 0.174) or Egger’s test (P = 0.277). In conclusion, this meta-analysis indicates that hypertension may be associated with an increased risk of prostate cancer. Considering the substantial heterogeneity and residual confounding among included studies, further large-scale, well-designed prospective cohorts, as well as mechanistic studies, are urgently needed to confirm our preliminary findings.The previously reported association between hypertension and prostate cancer risk was controversial. We performed this systematic review and meta-analysis of all available studies to summarize evidence on this association. Studies were identified by searching PubMed, Web of Science and Chinese National Knowledge Infrastructure (CNKI) databases through January 2016. Pooled relative risks (RRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random-effects model. A total of 21 published studies were included in this meta-analysis. A significant increase in the risk of prostate cancer (RR 1.08, 95% CI 1.02–1.15,  Prostate cancer has the second highest incidence of all cancers in males worldwide, with 1,111,700 new cases and 307,500 deaths estimated to have occurred in 2012 et al.Recently, several researchers have explored whether hypertension is a potential risk factor for prostate cancer with conflicting results. Two case–control studies and two cohort studies89101213The detailed process of literature search is presented in 89101112131415161718192021222324252627P = 0.014) was observed among individuals with hypertension. There was statistically significant heterogeneity among included studies .The multivariable-adjusted relative risks (RRs) for each individual study and for the combination of all included studies are presented in Next, we performed stratified analyses by geographical region, study design, study quality, and number of cases . In the et al.et al.The influence of each study on the pooled RR was evaluated by repeating the overall analysis after omitting each study in turn. The results indicated that no single study dominated the combined RR. The 21 study-specific RRs ranged from a low of 1.06 (95% CI 1.00–1.12) to a high of 1.13 (95% CI 1.03–1.24) via omission of the study by Beebe-Dimmer et al.Cumulative meta-analysis is the process of repeated pooling of individual studies each time adding a new study. In this meta-analysis, we carried out the cumulative meta-analysis according to publication year. As shown in P = 0.174) or Egger’s test (P = 0.277).There was no obvious evidence of significant publication bias by Begg’s test  greater risk of prostate cancer. However, that pooled analysis only included 10 published studies, with a total of 4,343 cases. By contrast, the present meta-analysis included more recent studies and thereby had larger sample size ; potentially improved statistical power.The findings of this meta-analysis were in agreement with a previous meta-analysisThe exact mechanism underlying the positive association between hypertension and prostate cancer risk is not clear. It has been proposed that hypertension could increase the risk of prostate cancer through the activity of the sympathetic nervous system that can lead to androgen-mediated stimulation of prostate cancer cell growthOur study had several strengths. A total of 21 published studies with 24,366 prostate cancer cases were pooled in this meta-analysis, which might enhance the statistical power of the data analysis and thus provide more reliable estimates. Various stratified analyses and sensitivity analyses were performed to explore the sources of heterogeneity and assess the robustness of the combined risk estimate. The estimates for the most fully adjusted model reported in each study were extracted in this study to reduce the potential confounding effect.P < 0.001 for heterogeneity, I2 = 72.1%), which might distort the combined estimates. Heterogeneity is caused by variation in definitions and ranges of exposure, methods of exposure and outcome assessment, and population sources. Heterogeneity could also be attributed to the heterogeneity of the prostate cancer disease and the divergent results between hypertension and prostate cancer diagnosis and deathThere were also several important limitations that need to be considered in interpreting the results of this study. First, substantial heterogeneity was observed across individual studies  databases with the following search algorithm: (“hypertension” or “blood pressure” or “systolic pressure” or “diastolic pressure”) and (“prostate cancer” or “prostate neoplasm”) and (“cohort” or “case control” or “case-control”). In addition, the lists of references from retrieved articles and reviews were also checked to identify any additional eligible studies. No limitations on language or publication date were applied. This systematic review and meta-analysis was designed, performed, and reported based on the standards of quality for reporting meta-analysesi) the exposure of interest was hypertension; Hypertension is defined as a systolic blood pressure above 140 mmHg or a diastolic blood pressure above 90 mmHg. (ii) the outcome of interest was prostate cancer; (iii) study design was cohort, nested case-control or case-control; and (iv) the risk estimates with their corresponding 95% CIs were available (or enough data were provided to estimate effect size). If multiple publications reported data from the same study, the publication with the largest sample size was included in the meta-analysis.A study was included in this meta-analysis if it met all of the following criteria: . NOS is an eight-item instrument designed to assess selection (four items), comparability (one item), and exposure/outcome (three items). Each item represents one point, except for comparability (two points). Thus the range of potential scores is 0–9 points. A study is classified as high quality if the score is 7–9 points.Two investigators (Z.L. and X.X.) assessed the quality of each study independently by using the NOS  and any discrepancies were subject to discussion.According to rare disease assumption, the OR (odds ratio) was assumed approximately the same as RR, and the RR was designated as the study outcome. RRs and their 95% CIs were used to calculate and assess the strength of the relationship between hypertension and prostate cancer risk. A random-effects model reported by DerSimonian and LairdQ and the I2 indexQ was set to 0.1 (10%). The value of I2 was used to describe the degree of heterogeneity .Cochran Sensitivity analysis was conducted by omitting each study in turn and recalculating the combined RR to determine the influence of each study on the overall risk estimate. Cumulative meta-analysis was also performed by sorting the studies according to publication date.P values (set at 0.05).Begg’s test (rank correlation method)How to cite this article: Liang, Z. et al. Hypertension and risk of prostate cancer: a systematic review and meta-analysis. Sci. Rep.6, 31358; doi: 10.1038/srep31358 (2016).


The etiology of non-genetic intellectual disability (ID) is not fully known, and we aimed to identify the prenatal, perinatal and neonatal risk factors for ID.PubMed and Embase databases were searched for studies that examined the association between pre-, peri- and neonatal factors and ID risk  were calculated for each risk factor using random effects models, with tests for heterogeneity and publication bias.Seventeen studies with 55,344 patients and 5,723,749 control individuals were eligible for inclusion in our analysis, and 16 potential risk factors were analyzed. Ten prenatal factors , one perinatal factor (preterm birth) and two neonatal factors  were significantly associated with increased risk of ID.This systemic review and meta-analysis provides a comprehensive evidence-based assessment of the risk factors for ID. Future studies are encouraged to focus on perinatal and neonatal risk factors and the combined effects of multiple factors. Intellectual disability (ID) or mental retardation (MR) is a developmental disability characterized by significant limitations in both intellectual functioning and adaptive behavior. Its onset occurs before 18 years of age. ID can Numerous population-based studies have focused on specific non-genetic exposures as possible risk factors for ID. Many support the hypothesis that some prenatal , perinatal  and neonatal  exposures may increase the risk of ID, 7. HoweThe study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria (PRISMA) as shown in To be included in our analysis, the study had to: (1) evaluate the association between prenatal, perinatal, or neonatal factors and risk of ID, (2) have a cohort, case-control, or cross-sectional design, and (3) report odds ratios (ORs) and corresponding 95% confidence intervals (CIs) or other usable data. Studies were excluded if they: (1) did not eliminate the impact of genetic causes  on the risk of ID, (2) did not include a control group, or (3) overlapped with another study.The following data were independently collected by two reviewers (Jichong Huang and Tingting Zhu) from each of the included studies: name of the first author, year of publication, the country in which the study was conducted, study design, age at diagnosis, total number of cases and controls, exposure assessment methods, outcome assessment methods, ID diagnostic criteria, and risk factors.We only included risk factors that were evaluated in two or more studies. For each risk factor, we extracted the OR together with the 95% CI. When the OR was not provided in the study, we computed a crude OR.The methodological quality of each included study was independently assessed by two reviewers (Jichong Huang and Tingting Zhu) using the Newcastle-Ottawa Scale (NOS), 14. The2 tests. Data were considered statistically heterogeneous if I2 >50% and P was <0.1. Publication bias was assessed by conducting tests for funnel plot asymmetry[A separate meta-analysis was conducted for each risk factor and the pooled OR was calculated by using the fixed-effects model  or the random-effects model  , 16. Hetasymmetry. Begg’s asymmetry and Eggeasymmetry were alsA total of 1,263 studies (927 in PubMed and 336 in Embase) and an additional eight studies culled from other sources were identified after an initial search. After reading the titles and abstracts, 1227 studies were excluded for irrelevant to the prenatal, perinatal or neonatal factors and ID risk, and five studies were excluded because of duplication. After reading the full-texts of the remaining 39 studies, 22 studies were excluded because they did not assess the effect of genetic causes on the risk of ID (13 studies), did not include a control group (six studies), or lacked usable data (three studies). Consequently, our analysis ultimately included 17 studies with a total of 55,344 patients and 5,723,749 control individuals. The meta-analysis included 15 risk factors . The selection process is shown in The methodological quality scores of the included studies ranged from four to seven points. The appraisal details are presented in Tables 2 = 32%, P = 0.22), maternal tobacco use , and maternal asthma   , maternal black race , low maternal education , third or more parity , maternal alcohol use , maternal tobacco use , maternal diabetes , maternal hypertension , maternal epilepsy  and maternal asthma  . There w = 0.75) .2 = 93%, P <0.0001 for both)   and between ID risk and two neonatal factors: male sex  and low birth weight  . Individor both) .Publication bias was assessed for the factors examined in the pooled analysis of more than two studies Figs  and 3. SIdentifying patients with a high risk of non-genetic ID is important for early detection and intervention of ID, which would benefit both clinical practice and public health. To our knowledge, this study is the first systemic review and meta-analysis of the relationship between prenatal, perinatal, and neonatal factors and the risk of ID. This meta-analysis included 17 cohort or case-control studies with a total of 55,344 patients and 5,723,749 control individuals.The factors strongly associated with ID risk were advanced maternal age (>35 years), maternal black race, low maternal education, third or more parity, maternal alcohol use, maternal epilepsy, preterm birth, male sex, and low birth weight. Other significant factors with a lower strength of association (risk estimates less than 1.5) were maternal tobacco use, maternal diabetes, maternal hypertension and maternal asthma.The fetus is highly susceptible to changes in maternal conditions. Risk factors such as maternal toxicant exposure and metabolic disorders can significantly affect the genetically programmed brain development of the fetus. Previous studies have shown that maternal tobacco exposure, alcoholBefore the 21st century, advanced maternal age was considered to be >30 years. Several studies during that period investigated but could not confirm a relationship between maternal age and risk of ID owing to insignificant results, 26, 28.There were no significant associations between ID risk and young maternal age (under 20-year-old) or second parity. The reason may be the limited number of included studies and insufficient simple size. Young maternal age often indicates a low education level, which is also related to ID risk. However, some of the studies included in our meta-analysis did not control this confounder. Moreover, since young maternal age ranges from 16 to 20 years old, 37, a mTwo previous meta-analyses examined the relationship between IQ score and preterm birth, 39. BotSome limitations of this meta-analysis should be addressed. First, several studies presented only crude ORs and did not adjust for other potential confounders, which might have resulted in overestimation of the association between risk factors and ID. Second, the heterogeneity among studies was noted in most risk factors. This heterogeneity resulted from the different diagnostic criteria of ID, age of diagnosis, sample size, and exposure or outcome assessment methods among studies. Moreover, the number of studies in each meta-analysis limited our ability to investigate these factors. Third, only published data were included in this analysis.This systemic review and meta-analysis identified prenatal, perinatal and neonatal risk factors for ID. The findings of this study indicate that prenatal factors have been the focus for studies on ID risk. In the future, more studies that focus on perinatal and neonatal factors are required, and researchers should be encouraged to investigate combinations of factors to a further study on the mechanisms leading to ID.S1 File(DOC)Click here for additional data file.S2 File(DOCX)Click here for additional data file.S1 Table(XLSX)Click here for additional data file.S2 Table(XLSX)Click here for additional data file.


MicroRNAs (miRNAs) are a family of endogenous, small and non-coding RNAs that regulate gene expression negatively at the post-transcriptional level by suppressing translation or degrading target mRNAs, and are involved in diverse biological and pathological processes. Single nucleotide polymorphisms (SNPs) which are located in the miRNA-coding genes may participate in the process of development and diseases by altering the expression of mature miRNA. Recent studies investigating the association between hsa-mir-499 polymorphism (rs3746444) and cancer risk have yielded conflicting results.In this meta-analysis, we conducted a search of case–control studies on the associations of SNP rs3746444 with susceptibility to cancer in electronic databases. A total of 31 studies involving 12799 cases and 14507 controls were retrieved and the strength of the association was estimated by pooled odds ratios (ORs) and 95% confidence intervals (CIs). Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in controls. Subgroup analyses were done by racial descent and cancer type. Publication bias of literatures was evaluated by visual inspection of funnel plots and the linear regression asymmetry test by Egger et al. Sensitivity analysis was conducted by excluding one study at a time to examine the influence of individual data set on the pooled ORs.Overall, significant association between rs3746444 polymorphism and susceptibility to cancer was identified in TC versus TT and TC/CC versus TT (dominant) models. In the stratified analyses, increased risks were found in Asians, but not in Caucasians in all comparison models tested. Moreover, significant association with an increased risk was found in Chinese population. Also, much higher significant association with increased cancer risks were found in Iranian population. In different cancer types, a decreased risk was found in esophageal cancer.Our meta-analysis suggested that hsa-mir-499 rs3746444 T > C polymorphism is associated with the risk of cancer in Asians, mainly in Iranian and Chinese population. However, rs3746444 T > C polymorphism is negatively associated with the risk of esophageal cancer.The online version of this article (doi:10.1186/s12881-014-0126-1) contains supplementary material, which is available to authorized users. C. elegans by several groups, simultaneously [. In the last decade, the study of miRNA biology has attracted remarkable attention, resulting in rapid advances, and revealing miRNAs as key gene regulators in diverse biological pathways [In early 1990s, microRNAs (miRNAs) were first discovered through analysis of developmental timing mutants in aneously . In the pathways . miRNAs pathways , developpathways , drug repathways , metabolpathways , cardiovpathways  and malipathways .miRNAs are hairpin-derived RNAs ~20-24 nucleotides long, which post-transcriptionally repress the expression of target genes usually by binding to the 3′-untranslated region (3′ UTR) of messenger RNA (mRNA) in a broad range of organisms in both normal physiological and disease contexts ,12. The Recent evidences support that single nucleotide polymorphisms (SNPs), occurring in DNA sequences of miRNA-coding genes or in miRNA-binding site in mRNAs, contribute to the biogenesis and functions of miRNAs . Gain/loReports on the associations between SNPs in pre-miRNA or SNPs in binding sites in 3′ UTR of miRNA targeting mRNAs and human diseases have provided new insights into the molecular mechanisms of pathophysiological processes in humans. rs4846049 (G > T) of MTHFR gene is associated with increased risk for coronary heart diseases, and the potentially pathogenetic mechanism may be SNP-modified posttranscriptional gene regulation by miRNA-149 to MTHFR . MiR-196To date, many studies explored the association between rs3746444 T > C SNP in hsa-mir-499 and susceptibility to diseases, such as breast cancer –26, lungThe results of these observations remain controversial and inconclusive. In the present study, we conducted a meta-analysis in order to derive more precise and more comprehensive estimation of the associations between the SNP hsa-mir-499 rs3746444 T > C and susceptibility to cancers to quantify the potential between-study heterogeneity.We performed a publication search in PubMed, EMBASE, ISI Web of Science, The Cochrane Library, ScienceDirect, EBSCO, Ovid, Wiley Online Library, and HighWire databases with the following search terms: (miR-499 OR rs3746444) AND (cancer), by two independent investigators . Hand searches were also performed to identify additional articles in the reference lists of included articles not retrieved by initial electronic search. Publication date and publication language were not restricted in our search. All studies matching the inclusion criteria were retrieved for further examination and data extraction. All of the investigators have received training in literature search, statistics and evidence-based medicine.Studies included in current meta-analysis had to meet all the following criteria: (1) evaluated the associations between the hsa-mir-499 rs3746444 polymorphism and cancer risk; (2) studied on human beings; (3) diseases were confirmed by histology, imaging or pathology; (4) a case–control design; (5) detailed genotype data were provided for the calculation of odds ratio (OR) and 95% confidence interval (CIs); (6) if serial studies of the same population from the same group were reported, the latest study was included. Studies were excluded when they represented duplicates of previous publications, or were meta -analyses, meeting abstracts, letters, reviews, or editorial articles.Two investigators (Chen Chen and Shenglan Yang) independently extracted data from the included studies using a standard protocol and data-collection form according to the inclusion criteria listed above, and reached consensus on all items. Data extracted from eligible studies included the first author’s name, year of publication, country of origin, ethnicity, cancer type, genotyping method, total numbers of cases and controls, and genotype frequencies of cases and controls. For study including subjects of different countries of origin group from same ethnicity, we combined them together. The ethnic descents were categorized as Caucasian or Asian. If different results were generated, the two authors would check the data and have had a discussion to come to an agreement. Two senior investigators (Yan Wang and Dao Wen Wang) were invited to the discussion if disagreement still existed.P < 0.05 was considered representative of a departure from HWE.For each study, the departure of frequencies of hsa-mir-499 polymorphism from expectation under Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in controls. P < 0.05 was considered as statistically significant. Pooled ORs were calculated for allele frequency comparison  and CC versus TC/TT (recessive)), respectively. Subgroup analyses were done by racial descent and cancer type. Statistical heterogeneity among the studies was estimated using chi-square-based Q-test, a P value greater than 0.1 indicates no significant heterogeneity and the pooled OR was estimated by the fixed-effects model (the Mantel-Haenszel method); otherwise, the random-effects model (the DerSimonian and Laird method) was employed [P value of Egger’s test less than 0.05 was considered representative of statistically significant publication bias.Sensitivity analysis was conducted by deleting one study at a time to examine the influence of individual data set on the pooled ORs.OR corresponding to 95% CI was used to assess the strength of association between hsa-miR-499 rs3746444 T > C polymorphism and susceptibility to cancer risk. The significance of the pooled OR was determined by the Z-test, and employed . An asymP values are two-sided.All of the statistical tests were performed with Review Manage  and STATA software version 11.0 . All the After first search in PubMed, EMBASE, ISI Web of Science, The Cochrane Library, ScienceDirect, EBSCO, Ovid, Wiley Online Library, and HighWire databases, 70, 76, 116, 0, 2080, 86, 23, 104, and 202 articles, respectively, were retrieved. Of these, 55 articles were relevant to the search words : OR = 1.11, 95% CI 1.01-1.23, P = 0.03; CC versus TC/TT (recessive): OR = 0.98, 95% CI 0.81-1.17, P = 0.79). Next, subgroup analyses were performed. Twenty-eight out of the thirty-one included studies were conducted in Asian population. In ethnicity subgroup analysis, significantly increased risks were found in Asians : OR = 1.14; 95% CI = 1.02-1.27, P = 0.02), consistently. This increased risk of cancer was especially significant in Iranian : OR = 2.23; 95% CI = 1.44-3.45, P = 0.0003) and Chinese population . However, no significant association between hsa-mir-499 rs3746444 T > C polymorphism and cancer risk was found in Caucasians in any of the genetic models tested. Further subgroup analysis based on cancer type revealed a decreased risk for esophageal cancer .The association between hsa-mir-499 rs3746444 polymorphism and susceptibility to cancer was analyzed in 31 independent studies. The results are shown in Table P > 0.05).Begg’s funnel plot and Egger’s test were performed to assess the publication bias of included studies. Symmetrical funnel plots were obtained in all comparison models Figure . FurtherExclusion of one study at a time was performed to examine the influence of the individual data set to the pooled ORs. Analyses were performed using STATA by means of the metainf program. Results showed that the pooled OR estimates were similar with those of the excluded studies Figure .Figure 3In the present study, hsa-mir-499 rs3746444 polymorphism and susceptibility to cancer was evaluated in different genetic models in 12799 cancer cases and 14507 controls. Significant association between rs3746444 polymorphism and susceptibility to cancer was identified in TC versus TT and TC/CC versus TT (dominant) models. Subgroup analysis absed on ethnicity revealed significantly increased risk in Asians (TC versus TT and TC/CC versus TT (dominant), but there was no significant association in Caucasians in all genetic models. This association was especially marked in Iranians  and a significant association was also identified in Chinese (TC versus TT) However, subgroup analysis based on cancer type revealed a decreased risk for esophageal cancer (C versus T).Many studies investigated the role of SNPs presented in precursor and mature miRNAs, and their influences on susceptibility and progression of various diseases. miRNA-associated SNPs can have direct or indirect effects: 1) direct effects are produced by the SNPs in the pri-miRNA, pre-miRNA or mature miRNA that impair or enhance miRNA processing or function; 2) indirect effects are derived from the SNPs in miRNA promoters that affect transcription and SNPs in an mRNA that create or destroy a target site .Genome-wide patterns of human polymorphisms in miRNAs and miRNA target sites in 3′ UTRs of mRNAs revealed that only ~10% of human pre-miRNAs have documented SNPs, and <1% of mature miRNAs have SNPs in the functional seed region . hsa-mirDifferent from past studies, we analyzed the specific association among different ethnic groups throughout Asia. In this meta-analysis, we first found that rs3746444 polymorphism was associated with increased cancer risk mainly in Asian population, especially in Chinese and Iranians. It is important to notice that, although rs3746444 polymorphism contributes to cancer risk in Chinese and Iranians, the genetic models are different. The genetic variations between Chinese Han population and Arabian population may contribute to the differences. Interestingly, we also found that rs3746444 polymorphism showed a decreased risk in esophageal cancer. This suggests that potentially different mechanisms may underlie tumorgenesis in different pathological backgrounds and the environment variations.It has been suggested that miRNAs may influence gene expression of ~30% of protein-coding genes by binding to the mRNA incompletely, and a miRNA may affect multiple target mRNAs involved in same pathophysiological progress . This meOur meta-analysis pooled the largest numbers of cases and controls from included studies, which significantly increases the statistical power but some limitations should be considered. Firstly, lack of the consideration of combined genetic factors together with environmental exposures, while a more precise analysis needs to be conducted if more detailed data are available. Secondly, although sensitivity analysis showed that each study can not affect the overall results, some heterogeneity was evident in some of the comparisons. This may be due to different ethnicities and different pathology. And expanding the sample size may yield a better result. Thirdly, some unpublished data  may potentially influence the results of our meta-analysis. At last, different genotyping strategies may contribute to the bias in the analysis.Recently several meta-analyses systematically reviewed the potential association of rs3746444 polymorphism with susceptibility to diseases –45,74–77In summary, though with limitations, our meta-analysis suggested that hsa-mir-499 rs3746444 T > C polymorphism is associated with the risk of cancer, especially in Asians, mainly in Chinese and Iranians. However, rs3746444 T > C polymorphism is negatively associated with the risk of esophageal cancer. Larger studies from different ethnic groups and studying different types of cancers with detailed information are needed to further clarify the association between rs3746444 polymorphism and cancer risk.


P = 0.03). The frequency of S allele was significantly higher in patients than that in controls . For the family-based study, the S allele of 5-HTTLPR was preferentially transmitted rather than non-transmitted from the parents to affected offspring (P = 0.013). The results of ANCOVA test revealed no significant association between the 5-HTTLPR polymorphism and severity of AN. Our findings suggested that 5-HTTLPR is able to confer susceptibility to AN in Han Chinese.Accumulating evidence has implied that serotonin system dysfunction may be involved in the etiology of anorexia nervosa (AN). Serotonin-transporter-linked promoter region (5-HTTLPR) polymorphism is the genetic variant coding for the serotonin transporter and has a modulatory effect on its expression. This study aimed to investigate the possible association between the 5-HTTLPR and the susceptibility and severity of AN in Han Chinese using a case-control (255 patients and 351 controls) and family based study (198 trios). Eating disorder examination was used to measure the severity of AN behavioral symptoms. For the case-control study, the 5-HTTLPR showed significant association with AN in our sample (genotypic  Anorexia nervosa (AN) is an eating disorder, characterized by excessive food restriction, typically arising from a morbid fear of weight gain that motivates patients to avoid eating. Although the pathogenesis of AN remains unknown, several lines of evidence supported the idea that AN is frequently associated with symptoms of anxiety, obsessive-compulsiveness and depression, and same pathophysiological mechanisms may underlie these symptoms .Serotonin (5-HT) is a major neurotransmitter in the mammalian central nervous system (CNS). 5-HT modulates various CNS physiological activities including food intake, the sleep-wake cycle, cognition, and a wide repertoire of emotional behaviors . CurrentGenetic epidemiological studies have assembled convincing evidence that AN is substantially influenced by genetic factors, and that the genetic component contributing to 50%∼70% of the variance in AN . The S aSo far, case-control studies have examined the association between 5-HTTLPR polymorphism and AN. Some preliminary findings have indicated a significant association of the S allele with AN ,8, but sAll participants provided written informed consent prior to inclusion in this project, and were treated in accordance with the Declaration of Helsinki. The study protocol and process was assessed and approved by the ethics committee at the Shanghai Mental Health Center. The Ethics Committee of the Shanghai Mental Health Center provided ethics approval for adolescent participants to provide their own consent rather than requiring consent for next of kin, caretakers or guardians.We performed both case-control and family-based analyses in this study. For the family-based study, 198 trios consisting of 594 subjects were recruited. All probands from the family-based study were also part of the case-control study, which is detailed as follows. Their parents self-reported no history of AN. For the case-control study, a total of 255 patients with AN were recruited from the Department of Clinical Psychology, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine. Each patient was assessed and diagnosed by at least two senior psychiatrists according to DSM- IV (American Psychiatry Association). The sample consisted of 13 male and 242 female patients with a mean age at entry into the study of 19.4±4.7 years.An additional 351 healthy control subjects  were recruited from hospital staff and students of School of Medicine in Shanghai, and then interviewed by a research psychiatrist according to the SCID-P . Control2), participants’ weight and height were evaluated by a trained research assistant using a stadiometer. All patients were weighted in light indoor clothing, without shoes. (2) Eating disorder examination: eating attitudes and behaviors were specifically investigated by means of the Eating Disorder Examination Questionnaire (EDE-Q). The EDE-Q is a semi-structured investigator-based interview specifically devoted to the assessment of ED psychopathology, providing different levels of descriptive data concerning current ED psychopathology. The EDE-Q global scale was used to assess the severity of ED behavioral symptoms. The EDE-Q has previously demonstrated good reliability and validity [All measures were administrated at prior to enrollment. (1) Physical assessment: to calculate body mass index  and 5′-GAGGGACTGAGCTGGACAACCAC-3′ (reverse). PCR was performed with the annealing temperature at 62°C for 33 cycles. The PCR products were subjected to electrophoresis in 2% agarose gels, stained with ethidium bromide and visualized under UV light.Blood samples were obtained from the participants and then Genomic DNA was isolated from whole blood using a Tiangen DNA isolation kit . The analysis of the 5-HTTLPR variant was done using PCR as the method described by Xu et al . The folhttp://analysis.bio-x.cn) [http://hydra.usc.edu/GxE). All tests were two-tailed and a significance level was set at P<0.05.We used SPSS 17.0  to perform either the t-test or the chi-square test to compare demographic characteristics between the AN and control groups. For the case-control analysis, the Hardy-Weinberg equilibrium, allele and genotype frequencies of 5-HTTLPR polymorphism were determined using SHEsis (io-x.cn) . The famP≺0.01).Social-demographic and clinical characteristics of our sample are reported in P = 0.38). Comparisons of genotype and allele frequencies for the polymorphism between patients with AN and control subjects are presented in P = 0.03). The frequency of S allele was significantly higher in patients than that in controls . Family-based test showed that genotype distribution of 5-HTTLPR conformed to Hardy-Weinberg equilibrium in the parents and no Mendelian inheritance error was found. Allele frequencies analysis is shown in P = 0.013). Under the assumption of a modest effect size and log additive model, the statistical power of our sample was more than 90% and 76% for the case-control and family-based analyses, respectively.5-HTTLPR has two common forms that are distinguished by a long and short allele depending on the insertion or deletion of 44bp. For the case-control study, the genotype distribution of the 5-HTTLPR polymorphism in control group was in accordance with Hardy-Weinberg equilibrium (A total of 177 unmedicated patients examined with the EDE-Q to evaluate pathological symptoms of AN. Then the scores of five factors of the EDE-Q were compared based on the genotypes of 5-HTTLPR. The results of ANCOVA test revealed no significant association between the 5-HTTLPR polymorphism and severity of AN .In the present study, we found significant difference in allele and genotype frequencies of 5-HTTLPR between the patient and control groups. Since the false-positive results may emerge due to the effects of population stratification in case-control investigation design, family-based study was carried out as an effective approach to follow up the findings from the case-control investigation . In the It is known that AN is a syndrome with a multifactorial etiopathogenesis involving psychological and biological factors . EpidemiAs a secondary aim, this study examined whether 5-HTTLPR was associated with specific symptom clusters. Our sample was divided into three groups on the basis of subject genotype and EDE-Q score differences between subjects with the different genotypes were analyzed. Data obtained showed that the 5-HTTLPR polymorphism is not associated with the severity of AN. This seems to suggest 5-HTTLPR is not likely to facilitate the possibility of developing these psychopathological traits. AN is one of the most heritable complex disorders. Previous studies have illustrated the influence of dopaminergic and serotonergic system on the psychopathological features displayed by patients with AN ,39,40,41When interpreting the results of this study, we would be remiss in not noting some limitations. Aside from the small sample size used in this study, there are two potential limitations that are worth noting. First, while subjects were all of Chinese origin, we could not completely exclude the possibility of a population structure effect in our sample . Second,In conclusion, our results presented herein indicated that 5-HTTLPR is able to confer susceptibility to AN in Han Chinese. For validation, further independent studies in larger samples are needed to confirm these preliminary observations and to establish other possible implications, such as the psychopathological traits of this disorder.


Osteoarthritis (OA) is the most common form of arthritis and has become an increasingly important public-health problem. However, the pathogenesis of OA is still unclear. In recent years, its correlation with mtDNA haplogroups attracts much attention. We aimed to perform a meta-analysis to investigate the association between mtDNA haplogroups and OA.2I test. Subgroup analysis was performed to explore the origin of heterogeneity.Published English or Chinese literature from PubMed, Web of Science, SDOS, and CNKI was retrieved up until April 15, 2014. Case-control or cohort studies that detected the frequency of mtDNA haplogroups in OA patients and controls were included. The quality of the included studies was evaluated by the Newcastle-Ottawa Scale (NOS) assessment. A meta-analysis was conducted to calculate pooled odds ratio (OR) with 95% confidence interval (CI) through the random or fixed effect model, which was selected based on the between-study heterogeneity assessed by Q test and A total of 6 case-control studies (10590 cases and 7161 controls) with an average NOS score of 6.9 were involved. For the analysis between mtDNA haplogroup J and OA, random model was selected due to high heterogeneity. No significant association was found initially , however, once any study from UK population was removed the association emerged. Further subgroup analysis demonstrated that there was a significant association in Spain population , but not in UK population. Also, subgroup analysis revealed that there was a significant correlation between cluster TJ and OA in Spain population , although not in UK population. No significant correlation was found between haplogroup T/cluster HV/cluster KU and OA.Our current meta-analysis suggests that mtDNA haplogroup J and cluster TJ correlate with the risk of OA in Spanish population, but the associations in other populations require further investigation. Osteoarthritis (OA), also known as degenerative arthritis and proliferative arthritis, is a chronic progressive disease characterized with degenerative changes and secondary hyperosteogeny of articular cartilage, which leads to pain and dysfunction of joints. OA is the most common form of arthritis, rare before 40 years old, and rising steeply with age. In fact, OA occurs in more than 50% of the population older than 65 years old The mitochondrion is a membrane-enclosed organelle that converts dietary intake into ATP by oxidative phosphorylation (OXPHOS) and meanwhile produces reactive oxygen species (ROS) which may lead to oxidative damage of the cell Mitochondrial DNA (mtDNA) encodes 13 of their mitochondrial proteins Provided with the studies published in the past year, it is possible to collect sufficient data to explore the authentic interrelation between mtDNA haplogroups and OA. Therefore, in an attempt to ascertain the correlation of mtDNA haplogroups and risk of OA, we performed a meta-analysis to strengthen the statistical power of individual studies.This meta-analysis was developed according to the PRISMA guidelines . A protoOsteoarthritis AND  AND , with details in http://www.opengrey.eu). The literature in these databases from inception to April 15, 2014 was searched by two separate reviewers. If more than one article was published with the same case series, only the study with the largest sample size was selected.Relevant studies published in English or Chinese were identified by a computerized search via 4 databases, including PubMed, Web of Science, Elsevier ScienceDirect (SDOS), and China National Knowledge Infrastructure (CNKI). The search strategy involved the use of the following key words: The studies to meet the following inclusion criteria were screened: (1) evaluating the association between haplogroups of mtDNA and the risk of OA; (2) case-control or cohort design; (3) sufficient data provided to calculate odds ratio (OR) with the corresponding 95% confidence interval (95% CI). Studies were excluded if they: (1) explored the correlation between haplogroups of mtDNA and the progression of OA, not the prevalence; (2) focused on other mtDNA mutation except haplogroups. All identified studies were reviewed independently by two investigators to determine if an individual study should be included in this study and the discrepancies were resolved by discussion.The following data were extracted from each study by two investigators independently: (1) name of the first author; (2) year of publication; (3) country; (4) ethnicity; (5) gender of subjects; (6) age of subjects; (7) diagnosis criteria; (8) types of OA; (9) methods of genotype; (10) conclusion of the study; (11) study type; (12) controlled confounders; and (13) numbers of genotypes in cases and controls. We contacted investigators for additional information when necessary.The quality of all the included studies was evaluated independently by two authors using the Newcastle-Ottawa Scale (NOS) assessment 2I test. A P value (Q test) ≥0.05 or 2I<50% was considered to demonstrate no obvious heterogeneity, and then a fixed-effect model (FEM) was applied to calculate the pooled OR, whereas a P value <0.05 or 2I≥50% was considered to indicate the presence of heterogeneity, and then a random-effect model (REM) was adopted P<0.05 was considered statistically significant.The degree of between-study heterogeneity was determined by Q test and The database and reference list search identified a total of 874 non-duplicated articles . No non-American College of Rheumatology (ACR) criteria The detailed characteristics of the included studies are shown in the The details of the quality evaluation for every study are shown in 2I = 80%, P<0.01) was revealed, a random effect model was selected. Overall, the results showed that there was no significant association between haplogroup J and the risk of OA  (P<0.01), but no significant association in UK population . No significant correlation was found between haplogroup T and risk of OA , with moderate between-study heterogeneity  (Since severe between-study heterogeneity for haplogroup J ( P>0.05) . The sub P>0.05) . Further2I = 76%, P<0.05), subgroup analysis stratified by country was performed. There was a significant correlation between cluster TJ and OA in Spain population , although no significant correlation in UK population   with mild between-study heterogeneity . Further subgroup analysis confirmed the irrelevance between cluster KU and OA  . No signU and OA . A margiU and OA .Sensitivity analysis was performed by removing any study at one time. For haplogroup J, once a study from UK population P = 0.202 and P = 0.707 separately; for haplogroup T: P = 0.151 and P = 0.462 separately; for cluster TJ: P = 0.050 and P = 0.462 separately; for cluster HV: P = 0.135 and P = 0.086 separately; for cluster KU: P = 0.752 and P = 0.221 separately)  .P = 0.05, so the trim and fill analysis was carried out to evaluate the impact of any asymmetry. However, the pooled estimate was not changed.For haplogroup TJ, the Egger's test showed that the publication bias was suspected with OA is a major cause of pain and impaired mobility in the elderly, and as the aging of population in modern society OA becomes an increasingly important public-health problem. OA is a multi-factor disease with both genetic and environmental causes In this study we found that there was an association between haplogroup J/cluster TJ and risk of OA once a study from UK population was removed. Subgroup analysis also revealed that there was a significant association between haplogroup J/cluster TJ and risk of OA in Spain population, but not in UK population. It seems that there is a marginal correlation between cluster HV and risk of OA in Spain population. The investigation in Asian population indicated that haplogroup G was a risk factor and haplogroup B was protective Considering the discrepancies of the association between mtDNA haplogroups and OA in different populations, several probabilities may be taken into account. Firstly, mtDNA haplogroup J consists of two major clades that can be further divided into more clades The exact mechanism underlying the association of mtDNA haplogroups and OA risk remains unclear. Mitochondria produce ROS that play an important role in apoptosis The present study has some limitations. First, all the included studies were case-control studies, which tended to contain selection bias. In addition, the included studies adopted various control groups, including hospital controls with ailments unrelated to OA In conclusion, our meta-analysis suggests that mtDNA haplogroup J and cluster TJ correlate with the risk of OA in Spanish population; however, the association in other populations is still not clear. Further investigations in different regions, with satisfying controls, and containing the data of mtDNA subhaplogroups are required to clarify the correlation and the underlying mechanism.Checklist S1The PRISMA checklist.(DOC)Click here for additional data file.Methods S1Search strategies in PubMed, Web of Science, SDOS and CNKI.(DOCX)Click here for additional data file.


Evidence is increasingly accumulated about multiple roles for the β2-adrenoceptor gene in asthma. The results were inconsistent partly due to small sample sizes. To assess the association between β2-adrenoceptor gene polymorphisms and asthma risk, a meta-analysis was performed.We comprehensively searched the PubMed, EMBASE, BIOSIS Previews databases and extracted data from all eligible articles to estimate the association between β2-adrenoceptor gene polymorphisms and asthma risk. The pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated.Thirty-seven studies involving 6648 asthma patients and 15943 controls were included in the meta-analysis. Overall, significant associations were found in allelic genetic model , recessive genetic model  for Arg/Gly16. Stratified by ethnicity and age, significant associations were also found in Asian population in allelic genetic model, recessive genetic model and addictive model. For Gln/Glu27, no significant association was found when we combined all eligible studies. Age stratification showed significant associations in adults in allelic genetic model and recessive genetic model, but no significant association was found among Asians and Caucasians in ethnicity stratification.This meta-analysis implied that the β2-adrenoceptor Arg/Gly16 polymorphism was likely to contribute to asthma risk in Asian population. Gln/Glu27 polymorphism might be a contributor to asthma susceptibility for adults. Asthma is a common chronic disorder of the airways, which is characterized by airway hyperresponsiveness, obstruction, and airway wall remodeling The β2-adrenoceptor (β2AR) mediates the physiological responses in the airway, which include bronchodilation, bronchoprotection, enhanced mucociliary clearance Therefore, we present the results of a comprehensively updated meta-analysis of all relevant published data to investigate the association between β2AR gene polymorphisms and asthma risk with focus on Arg/Gly16 and Gln/Glu27 polymorphism.” and “ADRB2 or β2-adrenergic or beta adrenergic or adrenergic or adrenoceptor or beta2 AR” and “polymorphism* or variant* or genetic* or mutant*”. No publication language restrictions were imposed. All the searchable studies were retrieved, and we also checked their references for other relevant publications. The detailed search strategy for this study is showed in We followed criteria of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) to perform this meta-analysis . Two inv2-Adrenoceptor gene polymorphisms and asthma risk, (2) There were at least two comparison groups, for example, asthma versus control (nonasthma) group, and (3) Genotype distributions in comparison groups should be available for estimating an odds ratio (OR) with 95% confidence interval (CI). Studies would be discarded if they met one of the following criteria: (1) Not relevant to β2-Adrenoceptor polymorphisms or asthma risk, (2) The design based on family or sibling pairs, (3) Reviews or abstracts without useful information. If the same patient population was reported in several publications, we included the most complete study in our meta-analysis. If original genotype frequency data were not reported, we sent an email to the corresponding author for additional data. Studies were excluded from our meta-analysis if their authors did not provide us with related data.The inclusion criteria of our study were as follows: (1) Human studies evaluating associations between βIn the data collection process, two investigators (H.X. and Y.H.) independently examined full manuscripts of eligible studies, and relevant data were extracted into predesigned data collection form. We verified accuracy of data by comparing collection forms from each investigator. Any disagreement was resolved by discussion, or a third author (Y.C.) would evaluate these articles. The following information was collected from each eligible study: first author's name, year of publication, original country, ethnicity, sample size, genotyping method, age, and genotype numbers in cases and controls.Publication bias of studies was assessed using funnel plot, and P<0.05 was considered statistically significant. In addition, publication bias was also evaluated via Egger’s linear regression test.2 was also used to test the heterogeneity among the included studies. A p value>0.10 for the Q-test indicates a lack of heterogeneity among the studies, then the pooled OR estimate of each study was calculated by the fixed effect model. Otherwise, the random effect model was used.We tested the Hardy-Weinberg equilibrium (HWE) in control group using the Chi-square test. The pooled ORs were calculated for allelic genetic model, additive genetic model, dominant genetic model and recessive genetic model, respectively. Subgroup analyses were performed in term of ethnicity and age. The heterogeneity between the studies was investigated by using Cochrane Q-test. IStatistical analyses were performed using the Revman5.2 software , STATA 12.0 software . A p value<0.05 was considered statistically significant, except for test of heterogeneity where a level of p value<0.10 was used.The flow chart in Among 37 studies included in the meta-analysis, 29 investigated the contribution of β2AR Arg/Gly16 polymorphism to asthma risk . OverallThere were 22 studies investigating the association between Gln/Glu27 polymorphism and asthma risk . One stuFor β2AR Arg/Gly16 polymorphism, there were statistically significant heterogeneities in all genetic models when all eligible studies were combined . We thus2 values<50%  has been productive genotyping method to test a vast number of single nucleotide polymorphisms and assess their relations with complex diseases and phenotypes Several strengths of this meta-analysis could be listed as follows. First, we followed a rigorous protocol of systematic review, identifying data from 3 different databases comprehensively. Second, we have conducted subgroup analysis, sensitivity analysis and Galbraith plots to explore the source of heterogeneity, suggesting the reliability of our study. However, the results of our meta-analysis should be interpreted with caution due to some unavoidable limitations. First, potential heterogeneity and confounding factors may have affected the analysis. Statistically significant and quantitatively moderate–to–high heterogeneities were found in all genetic model for Arg/Gly16, even if we have found out the potential heterogeneity contributors. Second, publication bias might result in the loss of studies, which subsequently could affect the meta-analysis results. The shapes of funnel plots revealed slight asymmetry for Arg/Gly16 and we should pay attention to this point. Third, asthma is a heterogeneous group of conditions that result in recurrent, reversible bronchial obstruction The present meta-analysis suggests that β2AR Arg/Gly16 polymorphism may be an important genetic factor in the overall risk for developing asthma, especially in Asian population, and Gln/Glu27 polymorphisms may be a contributor to asthma susceptibility for adults. GWAS or more case–control studies with explicit diagnosis criteria and rigorous quality control are needed to support this finding in various ethnic groups.Table S1Arg/Gly16 genotypes among patients with asthma and controls included in the meta-analysis.Distribution of (DOC)Click here for additional data file.Table S2Distribution of Gln/Gln27genotypes among patients with asthma and controls included in the meta-analysis.(DOC)Click here for additional data file.Dox S1PRISMA 2009 Statement checklist.(DOC)Click here for additional data file.Dox S2Search strategies for this study.(DOC)Click here for additional data file.


KRAS genotype can benefit from it. We hypothesized that personal genetic heterogeneity might be the main cause leading to obvious difference in its clinical efficacy. A retrospective study including 82 mCRC patients treated with chemotherapy plus cetuximab and a comprehensive meta-analysis containing 2831 cases within sixteen eligible studies were conducted to investigate the possible association between FCGR2A H131R and FCGR3A V158F and clinical outcome of mCRC patients treated with anti-EGFR mAb based therapy. Results of the retrospective study showed that H131R within FCGR2A or V158F within FCGR3A were not associated with clinical outcome in 82 KRAS wild chemorefractory mCRC patients in co-dominant, dominant, recessive, over-dominant, allele genetic models. However, the comprehensive meta-analysis with the largest of sample size obtained the significant result between FCGR3A V158F and PFS  and OS . These findings indicate that KRAS wild chemorefractory mCRC individual harbored genotype FF of V158Fcan benefit from anti-EGFR mAb adjuvant therapy in terms of PFS and OS, and it may be useful genetic biomarker to predict clinical survival of mCRC individuals with anti-EGFR mAb based therapy.Anti-EGFR monoclonal antibodies (mAb) such as cetuximab, panitumumab are one kind of efficacious targeted drugs in treatment of metastatic colorectal cancer (mCRC). However, only a small proportion of patients harbored wild- Colorectal cancer (CRC) is one of the most common lethal malignancies in the United States and China , 2. WithKRAS mCRC patients in combination with chemotherapy as first and second lines as well as in monotherapy as third line drug [Cetuximab, a chimeric immunoglobulin 1 monoclonal antibody that targets the extracellular domain of the EGFR, has been validated to be effective in providing clinical benefit in wild-ine drug –7. Howevine drug , revealiine drug . TherefoKRAS mutation [KRAS mutated patients also showed to respond to cetuximab [FCGR2A and FCGR3A may contribute to abnormal secondary spatial structure and function of the products, leading to different binding affinity to cetuximab. H131R and V158F are two common single nucleotide polymorphisms (SNPs) which are located in the third and fifth exon of FCGR2A and FCGR3A, respectively, and two loci appear to be associated with clinical outcome in hematological malignancies and breast cancer with treatment of rituximab and trantuzumab, respectively [FCGR3A could benefit from the combination therapy including rituximab [FCGR2A was significantly associated with a shorter event-free survival in breast cancer patients with sequentially given transtuzumab in UNICANCER-PASCO4 trial [The molecular mechanisms underlying response to cetuximab are still substantially unclear; it is that cetuximab acts by means of inhibition of EGFR signal pathway or activation of antibody-dependent cell cytotoxicity (ADCC) . Howevermutation , 12, andetuximab . These eetuximab . ADCC isectively , 15. Folituximab  and genoO4 trial . Some stO4 trial –20.FCGR2A H131A and FCGR3A V158F with clinical outcome of 82 wild-KRAS chemorefractory mCRC patients undergoing cetuximab adjuvant therapy. Additionally, a comprehensive meta-analysis including prospective and retrospective studies was carried out to confirm the clinical finding.In this study, we aimed to investigate the association of KRAS were included in our study. 52 and 30 were colon and rectal cancer patients, respectively. All of them were TNM-IV stage patients and treated with chemotherapy plus cetuximab. However, only 6 CR, 44 PR, 15 SD and 17 PD were observed in 82 mCRC individuals, respectively. The genotype distributions of H131R within FCGR2A and V158F within FCGR3A were in Hardy-Weinberg equilibrium   and DCR  in co-dominant, dominant, recessive, over-dominant and allele genetic models, respectively. No statistical significant difference in response to cetuximab based therapy  or DCR  based on FCGR3A V158F was observed. Also, there was no significant association between FCGR combined genotype and ORR (P = 0.642 for RR or VV vs. H and F) and DCR (P = 0.554 for RR or VV vs. H and F) in present study.The influence of the two SNPs on the clinical efficacy and survival were described in Table FCGR2A were 6.0 and 6.0 months, and 5.5, 7.0, 6.0, 6.0, 6.0, 6.0 months for genotype HH, HR, RR, HR/RR, HH/HR, HH/RR of FCGR2A, respectively. However, H131R wasn't associated with PFS in co-dominant , dominant , recessive , over-dominant  and allele  models. The median OS of cases carrying H131R genotypes and alleles was 13 months, and there was no significant difference in OS in comparison of HR vs. HH , RR vs. HH , HR/RR vs. HH , RR vs. HR/HH , HR vs. HH/RR , allele R vs. H , respectively. Patient harbored genotype FV , VV  and FV/VV  of V158F within FCGR3A were not shown a statistically longer or shorter PFS and OS than those individuals harbored genotype FF, respectively, no significant association was observed in recessive , over-dominant , allele  models. Meanwhile, PFS  and OS  of the cases harbored genotype RR or VV weren't shown significant difference when compared to cases with allele H and F  and KRAS wild population patients , and individuals harbored genotype FF showed a longer OS than those carrying genotype VV of FCGR3A V158F only in overall population   and our study were included in this comprehensive meta-analysis to further evaluate the association of  therapy –31. The FCGR2A H131R and FCGR3A V158F and clinical outcome of mCRC patients with treatment of anti-EGFR mAb based therapy. With limitation of small sample size, our retrospective study showed no significant association between FCGR2A and FCGR3A polymorphisms and clinical outcome in 82 wild-KRAS chemorefractory mCRC individuals treated with chemotherapy plus cetuximab. However, the robust results of meta-analysis showed that genotype FF within V158F was significant associated with a longer PFS and OS than FV/VV and VV genotype in overall and KRAS wild population, respectively. These findings suggested that KRAS wild chemorefractory mCRC individual harbored genotype FF of V158F could benefit from anti-EGFR mAb based therapy in terms of PFS and OS, and the genotype could be used as a genetic biomarker to predict clinical prognosis of wild-KRAS mCRC patients with adjuvant treatment of anti-EGFR mAb.This study, to the best of our knowledge, is the first report that combined a retrospective study and a comprehensive meta-analysis with the largest sample size for estimating the association between in vitro and in vivo [FCGR2A and FCGR3A, respectively. FCGR2A-H allele and FCGR3A-V allele and VV genotype were associated with higher affinity to lgG2, lgG1 and lgG3 than others [FCGR2A and FCGR3A affected their receptor's specific binding-domain of IgG, leading to different antitumor effect in mCRC patients with anti-EGFR mAb based therapy.ADCC is considered as an important mechanism for the antitumor effect of anti-EGFR mAb in mCRC patients , 32. Cet in vivo –35. H131n others , respectFCGR polymorphisms and efficacy of trantuumab and rituximab demonstrated that FCGR2A H131R and FCGR3A V158F could predict clinical efficacy and survival of patients with breast cancer and lymphoma, respectively [FCGR2A H131R and FCGR3A V158F were associated with clinical outcome of mCRC patients with cetuximab in a small sample size [FCGR2A H131R and FCGR3A V158F and clinical outcome in chemotherapy plus cetuximab treated mCRC patients in terms of ORR, DCR, PFS and OS in retrospective study. Moreover, H131R within FCGR2A wasn't associated with ORR, DCR, PFS and OS in overall and KRAS wild subgroups in the meta-analysis, indicating that the polymorphism of FCGR2A might be not involved in anti-EGFR mAb induced ADCC effect and it could not predict clinical outcome of cetuximab based therapy in wild-KRAS mCRC patients. Nonetheless, V158F within FCGR3A was significantly associated with PFS in dominant genetic model in overall and KRAS wild populations and genotype VV of the loci was significantly associated with a shorter OS in overall population in the meta-analysis. These findings suggested that V158F of FCGR3A was involved in clinical survival of anti-EGFR mAb treated mCRC individual, and genotype FF could be used as a prognostic biomarker to predict survival of anti-EGFR mAb treated mCRC patients in overall population, especially KRAS wild carrier. Our finding is in agreement with previous studies conducted by Zhang et al and Pander et al [Several studies concerning ectively , 38. Cohple size . Whereasple size . In our er et al , 30, reser et al , 19, 23.FCGR3A was associated a longer PFS and OS compared with genotype VV and VV/VF remains partly understand. Included individuals in our retrospective study and eligible studies in meta-analysis were all chemorefractory mCRC patients, and long-time's regular chemoradiotherapy and increasing burden of CRC leaded to a gradual decreased immunologic surveillance [in vitro [FCGR3A might contribute to decreased ADCC-triggered by NK cell [The possible reason why genotype FF of V158F within eillance , 26. NK eillance . Meanwhieillance . Additioeillance . Althougin vitro . However NK cell , 26, but NK cell , 42.FCGR2A H131R and clinical outcome in KRAS wild mCRC individuals with adjuvant cetuximab therapy, but KRAS wild chemorefractory mCRC individual harbored genotype FF of V158F can benefit from cetuximab based therapy in terms of PFS and OS, and it may be a prognostic factor to evaluate the clinical survival of wild-KRAS mCRC patients undergoing anti-EGFR mAb therapy. With limitation of the study, multi-central, well designed prospective studies with large sample size are warrant to further validate our findings.In conclusion, we fail to find the significant association between KRAS. The included individuals were treated with cetuximab plus conventional chemotherapy regimen such as CapeOX, FOLFIR1 and FOLFOX. Cetuximab was used 400mg/m2 dose at first, then 250mg/m2 subsequently, 21 day a cycle, and treated until cancer progression or unacceptable toxicity. This study was approved by the Institution Ethics Commission of Southeast University, and all included participants were signed informed consents.Patients with mCRC who diagnosed and treated in Nanjing First Hospital and Pingxiang People's Hospital between 2007 May and 2014 December were enrolled in our retrospective study. All of them were histologically proven TNM-IV stage and harbored with wild-KRAS status, and response evaluated results) were collected from the cases' medical records.In accordance with the Response Evaluation Criteria In Solid Tumors Criteria 1.0 (RECST 1.0), the cancer response to cetuximab therapy was evaluated every month at the time of hospitalization and the evaluated results were defined as complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD), respectively. Progression-free survival (PFS), overall survival (OS) and objective response rate (ORR) and disease control rate (DCR) were used as endpoints in our study. PFS and OS were calculated from the first date of cetuximab usage to the time of disease progression and death, respectively. Relevant data . The detail probe, primer sequence, PCR protocol and detection were in accordance to the study reported by Norton et al [Human genomic DNA was extracted from paraffin-embedded CRC tissues or EDTA anti-coagulated peripheral blood samples using TIANamp Genomic DNA Kit  and stored at −80°C till detection. Taqman-genotyping real-time PCR were selected to detect genotypes of on et al .FCGR2A/3A and cetuximab or CRC”, “rs1801274/rs396991 and cetuximab or CRC”, and “ H131R/V158F and cetuximab or CRC” dating end up to March of 2015. In addition, a manual searching in reference of relevant articles was carried out to obtain substantial studies. Relevant articles were identified as eligible study in accordance with following including criteria: (1) retrospective or prospective study was concerned FCGR2A/3A polymorphisms and clinical outcome of chemorefractory mCRC cases treated with adjuvant cetuximab”; (2) efficacy evaluation criteria was in accordance with RECST 1.0/1.1; (3) studies provided median survival time, number of cases, genotype distributions, ORR, DCR. On the contrary, review, correspondence, letter, meta-analysis, case report or studies without providing relevant data were excluded from the study. Relevant study search, eligible study identification, data extraction and statistics were conducted by two independent investigator (Hou-Qun Ying and Feng Wang) and any discrepancies were discussed to reach consensus or made final decision by the third investigator (Xiao-Lin Chen).In order to enhance statistical power of the study, a meta-analysis including all eligible studies was conducted to further confirm our results. Relevant article was screened in the Pubmed, Web of SCI and Wanfang databases in English and Chinese using search terms of “FCGR2A H131R and FCGR3A V158F in all cases were calculated by counting. Pearson χ2 test was selected to evaluate association between the loci genotypes and response to cetuximab based treatment, and P < 0.05 were considered statistically significance. Kaplan-Meier curve with log-rank test and backward elimination multivariate Cox regression analysis were used to determine the influence of the FCGR2A and FCGR3A polymorphisms on PFS and OS, and the significant P-value was set at 0.05. Q test and estimated I2 were used to assess the heterogeneity between eligible studies, and Ph < 0.1 or I2 > 50% was considered as exist of significant heterogeneity. Overall effect of the meta-analysis was evaluated using Z test in the fixed model (Ph > 0.1) or the random model (Ph < 0.1) according to the heterogeneity test and Pz < 0.05 showed a statistical significance. Begg's funnel plot was selected to estimate the possible publication bias, and asymmetric funnel plot was considered as the existence of publication bias. All statistical analyses were performed using the SPSS statistical 17.0  and Stata 11.0 software .The genotype frequencies of


MTHFR) gene and the risk for congenital heart disease (CHD). Electronic literature databases were searched to identify eligible studies published before Jun, 2014. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI). The publication bias was explored using Begg's test. Sensitivity analysis was performed to evaluate the stability of the crude results. A total of 35 studies were included in this meta-analysis. For the MTHFR C677T polymorphism, we detected significant association in all genetic models for Asian children and the maternal population. Significant association was also detected in T vs. C for a Caucasian paediatric population  and in both T vs. C  and the dominant model  for a Caucasian maternal population. For the MTHFR A1298C polymorphism, the association was detected in CC vs. AC for the Caucasian paediatric population . Our results support the MTHFR -677T allele as a susceptibility factor for CHD in the Asian maternal population and the -1298C allele as a risk factor in the Caucasian paediatric population.The aim of our study was to evaluate the association between polymorphisms in the methylenetetrahydrofolate reductase ( Congenital heart disease (CHD) is the most frequently occurring congenital disorder in newborns and is the most frequent cause of infant death from birth defects. The aetiology of CHD is largely unknown. Epidemiological studies reveal a significant environmental contribution to the pathogenesis of CHD134MSX1 and STX18 genes was associated with the risk of ostium secundum atrial septal defect (ASD)NRP1 on 10p11 significantly increased the risk of Tetralogy of Fallot (TOF)HOMEZ and PLAGL1 as pathogenic genes in Chinese patients with isolated ventricular septal defects (VSDs)8The importance of genetic factors in the development of CHD is also supported by recent data from genome-wide association studies (GWASs). Data from these studies have confirmed that a region on chromosome 4p16 adjacent to the MTHFR) gene is located on chromosome 1 at 1p36.3. MTHFR is the key metabolic enzyme of homocysteine (Hcy). It catalyses 5,10-methylenetetrahydrofolate reduction to 5-methyltetrahydrofolate, which as a methyl donor induces Hcy remethylation to methionineMTHFR gene has been described, which results in the conversion of the amino acid alanine to valine at position 226 in the protein. This mutation was associated with a 50% reduction of MTHFR enzyme activity, an increase in plasma Hcy concentration and a decrease in plasma folic acid concentration. Another polymorphism  is located in exon 7, within the presumptive regulatory domain, and results in a glutamate-to-alanine change with decreased enzyme activity in vitroMTHFR polymorphisms play important roles in diseases. For example, neural tube defects and pregnancy complications appear to be linked to impaired MTHFR function13The 5,10-methylenetetrahydrofolate reductase  to investigate the association between MTHFR polymorphisms (C677T and A1298C) and the risk of CHD.Since Wenstrom first noted an association between Jun, 2014. The following keywords were used for searching:  AND (“polymorphism*” OR “variant*”) AND (“methylenetetrahydrofolate reductase” OR “MTHFR”). The most complete and recent results were used when there were multiple publications from the same study group. The references of reviews and retrieved articles were also searched simultaneously to find additional eligible studies.We conducted a comprehensive search of Embase, Ovid, Web of Science, the Cochrane database, Medline (PubMed), the Chinese Biomedical Literature Database , the database of National Knowledge Infrastructure  and the full paper database of Chinese Science and Technology of Chongqing  to identify suitable studies published before MTHFR polymorphisms in CHD; 2) case-control or case-cohort study; 3) proper CHD diagnosis criteria; 4) original data; 5) human subjects, not animal studies. We expected the clinical assessment of the patients to include anthropometric measurement and physical examination for dysmorphism and malformation, and diagnostic studies to include chest X-ray examination, electrocardiogram, ultrasonic echocardiogram, etc. Studies would be excluded if the necessary information could not be obtained.Two investigators reviewed all identified studies independently to determine whether an individual study was eligible for inclusion. The selection criteria for studies to be considered for this meta-analysis were as follows: 1) Two investigators extracted the data independently, and a third investigator reviewed the result. The following information was extracted from each study: first author, year of publication, study population , the number of patients and controls in the study, genotype information, genotype methods, and main types of CHD. If any data essential to the analysis were not available from a study, best efforts were made to contact the authors to fill in the missing data.MTHFR (C677T and A1298C) polymorphisms from each study were determined by the allele counting method19HWE) is the most fundamental rule of population genetics. It prescribes the genotype frequencies at a locus in terms of its allele frequencies in a population. In the most general form, it states that selection, migration, and random genetic drift occur with random mating in a population in the absence of mutationHWE for the distribution of the allele frequencies was analysed by Fisher's exact test in control groups. We examined the contrast of a vs. A, aa vs. AA, aa vs. Aa and also examined the recessive genetic model (aa vs. AA+Aa) and the dominant genetic model (Aa+aa vs. AA). The associations between MTHFR polymorphisms and CHD susceptibility were estimated by OR and its 95% CI. The significance of the pooled OR was determined by the Z-test; P < 0.05 was considered statistically significant. To evaluate the specific effects of ethnicity, stratified analyses were performed.Allele frequencies for the P < 0.122I2 metric (I2 = (Q - df)/Q × 100%; I2 < 25%, no heterogeneity; I2 = 25–50%, moderate heterogeneity; I2 = 50–75%, large heterogeneity; I2 > 75%, extreme heterogeneity). When the effects were assumed to be homogenous , the fixed-effects model was used; otherwise, the random-effects model was more appropriate242527P < 0.05 was considered representative of statistically significant publication bias. All analyses were performed using STATA software, version 10.0 , Review Manager  and R statistical software .Heterogeneity across the eligible studies was tested using the Q-test, and the results were considered statistically significant when MTHFR polymorphism and CHD were identified. However, after reading the full articles and contacting the authors, we excluded five meta-analysis studies2930313234353615173940414243444546474849505152535455565758596061626364656667686970A total of 126 abstracts that met the inclusion criteria were retrieved through the databases. Two reviewers then selected the relevant studies independently. Forty-five relevant studies that described the association between the MTHFR –677T allele frequency determined using the random-effects model was 28.99% (95 CI: 26.14%–32.02%) in the Caucasian paediatric population and was 42.28% (95% CI: 34.17%–50.83%) in the Asian paediatric population. There was no heterogeneity among the Caucasian and Asian maternal population studies. The MTHFR –677T allele frequency was 31.76% (95 CI: 30.14%–33.43%) in the Caucasian maternal population and was 41.51% (95% CI: 37.50%–45.64%) in the Asian maternal population.The pooled The pooled –1298C allele frequency in the fixed-effects model was 33.12% (95 CI: 29.80%–36.61%) in the Caucasian paediatric population and was 31.09% (95% CI: 25.34%–37.46%) in the Caucasian maternal population using the random-effects model.MTHFR C677T polymorphism and the risk of CHD for each study. When all the eligible studies were pooled in the overall population of children with random-effects models, significant associations were observed in all genetic models: T versus C , TT versus CC , and TT versus CT , the dominant model , and the recessive model , TT versus CC , TT versus CT , the dominant model , and the recessive model  in Caucasian children, and for T versus C , dominant model  in the Caucasian maternal population. In addition, significant associations were found when all studies were pooled in fixed or random-effects models for all genetic models in Asian children and the maternal population. The main results of meta-analysis are shown in In the stratified analysis by ethnicity, significant associations were found when all studies were pooled with fixed or random-effects models for T versus C , and for the recessive model  in the overall paediatric population. The main results of the meta-analysis are shown in We investigated the association between the P = 0.032; In the analysis stratified by ethnicity, significant associations were found in the Caucasian paediatric population when all studies were pooled in the fixed-effects model for CC versus AC  with the risk of ostium secundum ASDTBX15; P = 8.44 × 10−10) and 4q31.1  were associated with congenital heart malformations in Han Chinese populationsMany studies have demonstrated that genetic factors play important roles in the pathogenesis of CHD. In our previous studies, we have detected several novel variations of the MTHFR gene is located on chromosome 1 at 1p36.3. The major product of the MTHFR gene is a catalytically active 77 kDa protein that catalyses the conversion of 5,10-methylenetetrahydrofolate into 5-methyltetrahydrofolate, the major circulating form of folate. Two common genetic polymorphisms associated with reduced MTHFR activity have been identified. The C677T polymorphism is located in exon 4 at the folate-binding site and results in an alanine-to-valine substitution. In healthy homozygous subjects, the 677TT genotype is associated with higher total Hcy and lower folate plasma level. The other polymorphism (A1298C) is in exon 7 within the presumptive regulatory domain and results in a glutamate-to-alanine change. Heterozygosity and homozygosity are associated neither with higher total Hcy nor lower folate plasma concentration. The MTHFR gene polymorphisms are directly linked with many diseases20MTHFR C677T polymorphism is associated with the risk of myocardial infarction in young/middle-aged Caucasians and is associated with susceptibility to preeclampsia20In 1999, Kapusta and associates first reported that maternal hyperhomocysteinaemia is correlated with an increased risk of CHDsMTHFR genotype and the risk of CHD. In fact, in the last few years, several case–control studies were performed on this topic. However, the results are inconclusive. The two most recent meta-analyses for associations between polymorphism and CHD also led to conflicting conclusions. By reviewing all studies published before April, 2011, Yin and co-workers suggested that the foetal and paternal MTHFR C667T gene may be associated with an increased occurrence of CHD2010, Mamasoula and co-workers indicated that the same polymorphism, which directly influences plasma folate levels, is not associated with CHD risk2930MTHFR A1298C polymorphism and CHD by meta-analysis. We are indebted to Dr. Christensen from McGill University for kindly allowing us access to his previously un-published data for this meta-analysis.A number of studies have investigated the association between MTHFR C677T polymorphism and susceptibility to CHD for all genetic models in all paediatric and maternal populations, especially in the Asian population. We also detected a significant association in the genetic model for T vs. C in the Caucasian paediatric population and in T vs. C and TT vs. CT for the Caucasian maternal population (Our results indicate that the frequency of the putative risk allele -677T was 28.99% in Caucasian children and 31.76% in the Caucasian maternal population, whereas the frequency of -677T was 42.28% in Asian paediatric and 41.51% in the Asian maternal population. In addition, the pooled –1298C allele frequency was 33.12% in Caucasian children and 31.09% in the Caucasian maternal population. The meta-analysis results showed that associations exist between the pulation . In our pulation . The respulation .Some limitations of this meta-analysis should be discussed. First, significant heterogeneity was observed in some genetic models when we pooled ORs. Under this condition, we used the random-effects model to pool the data. Sensitivity analysis was performed to evaluate the stability of the crude results. Second, publication biases appear to substantially contaminate the literature with regard to some genetic associations. The results of the trim and fill method demonstrated that the publication biases may affect the stability of positive results.MTHFR –677T allele as a susceptibility factor for CHD in the Asian maternal population and the -1298C allele as a risk factor in the Caucasian paediatric population. Because of the heterogeneity and publication bias, we believe that other positive results may not be stable in our meta-analysis. A large number of homogeneous studies should be performed to evaluate these crude results in the future.In conclusion, our results support the Conception and design of the study: C.X. and L.M.L. Acquisition of data: H.L., J.X.Z. and H.W.W. Analysis and interpretation of the data: C.X., H.L., J.X.Z., Y.W., C.P.N., Z.L. and B.B.Z. Writing and revision of the manuscript: C.X., L.M.L. G.W.H. All authors reviewed the manuscript.