Chinese populations have a higher proportion of intracerebral hemorrhage (ICH) in total strokes. However, the reasons are not fully understood.To assess the differences in frequency of major risk factors between ICH and ischemic stroke (IS) in Chinese versus white populations of European descent, we systematically sought studies conducted since 1990 that compared frequency of risk factors between ICH and IS in Chinese or white populations. For each risk factor, in Chinese and Whites separately, we calculated study-specific and random effects pooled prevalence and odds ratios (ORs) for ICH versus IS.Six studies among 36190 Chinese, and seven among 52100 white stroke patients studied hypertension, diabetes, atrial fibrillation (AF), ischemic heart disease (IHD), hypercholesterolemia, smoking and alcohol. Pooled prevalence of AF was significantly lower in Chinese. Pooled ORs for ICH versus IS were mostly similar in Chinese and Whites. However, in Chinese–but not Whites–mean age was lower (62 versus 69 years), while hypertension and alcohol were significantly more frequent in ICH than IS . Hypercholesterolemia and smoking were significantly less frequent in ICH in Whites, but not Chinese, while IHD, AF and diabetes were less frequent in ICH in both.Different risk factor distributions in ICH and IS raise interesting possibilities about variation in mechanisms underlying the different distributions of pathological types of stroke between Chinese and Whites. Further analyses in large, prospective studies, including adjustment for potential confounders, are needed to consolidate and extend these findings. Over the past few decades, stroke incidence has fallen by around 40% in developed countries, but increased more than 100% in developing countries ,3.The distribution of pathological types of stroke may vary in different populations. Asians (including Chinese) were reported to have a higher incidence of intracerebral hemorrhage (ICH) . Our recThe search strategy was reported in detail previously . In brieWe included both community- and hospital-based studies of first-ever as well as recurrent strokes published by April 2013 , with prospective case recruitment, standard definition of stroke, and data collection from 1990 onwards (since brain imaging was not widely used before this) . StrokesWe extracted information from included studies on: first author, the geographical area and time period of the study; sources of recruitment and characteristics of patients (including age and sex); first-ever or recurrent strokes; definitions of stroke and its pathological types; CT or MR brain imaging rate; risk factor definitions; and numbers of patients with each risk factor for each pathological type. One author searched the literature and screened the studies, one selected studies and extracted data, and one cross-checked the data extractions, resolving uncertainties through discussion.2 and Cochrane Q χ2 statistics, and used a random effects model for meta-analyses since there was evidence of substantial heterogeneity [For each risk factor, where data were available from more than one study, we performed meta-analyses, calculating study-specific and random effects pooled prevalence in ICH and IS patients as well as odds ratios (ORs) for ICH versus IS with 95% confidence intervals (CIs), in Chinese and white populations separately. We assessed heterogeneity among studies with Iogeneity .http://www.ohri.ca/programs/clinical_epidemiology/oxford.htm). For quality assessment of the systematic review and meta-analysis, we used the modified AMSTAR  and PRISMA  checklists. The study protocol provided detailed questions and methods of scoring [For quality assessment (risk of bias) of the included papers, we used the Newcastle-Ottawa Scale .To assess whether pooled prevalence and ORs for each risk factor comparison differed between Chinese and Whites, or between geographically-defined subgroups within Chinese and white populations, we assessed between-group heterogeneity, using the within-group pooled estimates and their standard errors, and chi-squared statistics to test for statistical significance  ,14. In aOur search for studies in Chinese populations retrieved 6287 publications. From these, we included six eligible studies with a total of 36190 patients, of whom 35294 had an IS or ICH –20. FromCharacteristics of these included studies are shown in Tables Risk factors with data available from more than one study in both ethnic groups were hypertension, diabetes, atrial fibrillation (AF), ischemic heart disease (IHD), hypercholesterolemia, smoking and alcohol intake, and their definitions are summarised in The results of quality assessment for included papers using the Newcastle-Ottawa Scale were displayed in For hypertension, all studies had relevant data and definitions of hypertension, mainly based on a history of hypertension and/or antihypertensive treatment before stroke, or elevated blood pressure after stroke . DespiteAll Chinese and white studies had data on diabetes, with definitions based on history before stroke or elevated fasting plasma glucose levels. Except for one small study, all studies reported a lower prevalence of diabetes in ICH than in IS, with similar pooled ORs for ICH versus IS among Chinese and Whites . AF was consistently less frequent in ICH than in IS in both Chinese and Whites . In risk factor association for ICH versus IS, ORs were qualitatively similar between ethnic groups, but varied in size and significance. Both hypertension and alcohol intake were more frequent in ICH versus IS in Chinese but not white stroke patients, with significant between-group heterogeneity. Hypercholesterolemia and smoking were significantly less frequent in ICH versus IS in white but not Chinese stroke patients, while diabetes, AF and IHD were significantly less common in ICH in both. However, these differences should be interpreted with caution since evidence for between-group heterogeneity was marginal, and individual studies varied substantially within ethnic groups. In addition, other confounding factors such as age and sex, for which we could not adjust in our meta-analyses, might partly affect the results.Our systematic search revealed few large studies or reviews systematically comparing major risk factors in ICH versus IS. Recently, the INTERSTROKE study reported risk factors for all stroke, IS and ICH . Around The contrasts in the strength and significance of risk factor associations with ICH versus IS in our study could be due–at least in part—to differences in distributions of ICH and IS subtypes and in prevalence of these risk factors in Chinese and Whites. For example, a higher proportion of strokes in Chinese may be due to deep ICH (mainly due to hypertension) and lacunar IS among ICH and IS respectively, with a lower proportion due to lobar ICH  and non-lacunar subtypes. The proportion of cerebral amyloid angiopathy related ICH is lower in East Asians (including Chinese) than West populations, probably reflecting a higher incidence of hypertensive ICH rather than a lower incidence of cerebral amyloid angiopathy . These fMeta-analyses of data from prospective studies suggest a stronger association of blood pressure with stroke among eastern Asians (including Chinese) than white populations ,33. FurtSimilar meta-analyses from Asia Pacific Cohort Studies have shown that the associations of cholesterol with stroke and its pathological types are complex. There seems to be a positive association of increasing cholesterol with IS and a negative association with hemorrhagic stroke . HoweverAlcohol is suggested to have a dose-dependent relationship with hemorrhagic stroke, but a curvilinear relationship with IS—a protective effect for low to moderate intake and increased risk for high consumption ,36. In oPrevious studies had shown that recurrent stroke was more frequently associated with a history of transient ischemic attack, AF, male sex, and hypertension, but not with age, alcohol intake, smoking, diabetes, IHD, or serum cholesterol . AlthougOur subgroup analyses showed a significantly higher prevalence of hypertension, diabetes, and AF in Taiwanese than mainland Chinese IS patients. These results paralleled the international REACH registry, which reported a stepwise increase in the rates of hypertension, diabetes, hypercholesterolemia and obesity in Chinese patients, moving from mainland China to Hong Kong/Singapore/Taiwan, and to North America/Western Europe . These fThe current study has several major strengths. First, we used a search strategy to identify all the potentially relevant studies without limitation of language, which reduced the selection bias of including only English publications. Second, we included only studies based on a standard definition of stroke and reliable classification of its pathological types. Third, we carefully described characteristics, methods and risk factor definitions for each included study, and carried out rigorous meta-analyses for risk factor prevalence and risk factor associations for ICH versus IS in Chinese and white populations. Furthermore, we performed subgroup analyses within each ethnic group to explore geographic differences and possible explanations for the substantial heterogeneity encountered.Nevertheless, there were some limitations. First, despite extensive search, only a limited number of studies and few community-based studies fulfilled the inclusion criteria, which might not be fully representative of Chinese and white populations. Also, publication bias could not be assessed properly as there were inadequate numbers of included studies. Second, there was substantial heterogeneity among studies, which could arise from differences in age and sex distributions, methodology, definitions of risk factors, geographical areas, and true differences in risk factors between ICH and IS in different ethnic groups. Finally, because our meta-analysis was based on published data, we did not have individual patient data to adjust for potential confounders, and no available amyloid angiopathy data for analyses.In summary, we report some similarities but also several differences between Chinese and predominantly white populations of European descent in prevalence and associations of risk factors with ICH versus IS. These differences raise interesting possibilities about the mechanisms underlying the different distributions of pathological types of stroke in these two ethnic groups with their different genetic and environmental exposures. Further analyses in large, well-designed studies, with individual patient data available to allow adjustment for confounding factors, will help to consolidate these findings, providing useful information to enable effective strategies for stroke prevention.S1 Appendix(DOC)Click here for additional data file.S2 Appendix(DOCX)Click here for additional data file.S1 Fig(DOC)Click here for additional data file.S2 Fig(DOCX)Click here for additional data file.S3 Fig(DOC)Click here for additional data file.S1 Table(DOC)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOC)Click here for additional data file.S4 Table(DOC)Click here for additional data file.


ADH1B, ADH1C, ALDH1b1, ALDH2) and the risk of CAD in Han Chinese.Coronary artery disease (CAD) is a multifactorial and polygenic disease. The aim of this study was to examine the association between six polymorphisms of four alcohol metabolism relevant genes (ALDH1b1 rs2073478 and ALDH2 rs671 polymorphisms differed significantly between the two groups (P≤0.005), even after the Bonferroni correction. The most common allele combination was A-C-C-G-C-G  and its frequency was slightly higher in controls than in CAD patients (P = 0.067). After assigning the most common allele combination as a reference, allele combination A-C-C-T-C-A, which simultaneously possessed the risk alleles of rs2073478 and rs671 polymorphisms, was associated with a 1.80-fold greater risk of CAD. Further, a two-locus model including rs2073478 and rs671 that had a maximal testing accuracy of 0.598 and a cross-validation consistency of 10 (P = 0.008) was deemed as the overall best MDR model, which was further validated by classical Logistic regression model.This was a hospital-based case-control study involving 1365 hypertensive patients. All study subjects were angiographically confirmed. Genotypes were determined with ligase detection reaction method. There was no observable deviation from the Hardy-Weinberg equilibrium for six examined polymorphisms in controls. The genotype and allele distributions of ALDH1b1 and ALDH2 genes with the development of CAD in Han Chinese.Our findings provide clear evidence for both individual and interactive associations of  Coronary artery disease (CAD) is a complex disease with the interplay of multiple genetic and environmental factors precipitating its development Alcohol metabolism exhibits considerable variation between individuals. The bulk of evidence suggests that light-to-moderate alcohol consumption plays a protective role in the development of CAD, possibly due to its potential beneficial effect on lipids, insulin sensitivity and fibrinogen profiles For this project, we, in a genetically homogeneous population, examined the association between six polymorphisms of four alcohol metabolism relevant genes  and the risk of CAD both individually and jointly among Chinese hypertensive patients.This was a hospital-based case-control study involving 1365 hypertensive patients who were enrolled from the Department of Cardiology, the First Affiliated Hospital of Dalian Medical University as previously described In order to avoid confounding from the existence of hypertension, only hypertensive patients were enrolled in this study. Blood pressure was measured by certified examiners with a calibrated mercury sphygmomanometer with an appropriate adult cuff size. Hypertension was defined as a systolic blood pressure over 140 mm Hg or a diastolic blood pressure over 90 mm Hg or the current usage of antihypertensive drugs. In addition, all study subjects had undergone coronary angiography, and those with the presence of over 50% stenosis in at least one of the three major coronary arteries or major branches were assigned into the CAD group. Meanwhile, hypertensive patients with normal coronary angiography  and a negative history of any vascular event formed the control group. Patients were excluded if they had only simple spasm of coronary arteries, myocardial bridge or other non-coronary atherosclerotic lesions.According to the angiographic results, there were 679 subjects in the CAD group and 686 subjects in the control group. Subjects between the two groups were frequency-matched on age and gender.At the time of enrollment, age, gender, body weight and height were recorded. For CAD patients, age referred to the first onset age of CAD. Body weight was measured after removal of shoes and wearing light clothing only. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared.A fasting venous blood sample was drawn from each subject. Fasting glucose was measured in fluoride plasma by an electrochemical glucose oxidase method. Lipids including triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and other plasma biomarkers including blood urea nitrogen (BUN), creatinine and uric acid (UA) were measured enzymatically using available kits and auto analyzer . Plasma high sensitivity C-reactive protein (hsCRP) level was measured using a high-sensitivity ELISA kit .Genomic DNA was isolated from white blood cells by the phenol/chloroform extraction method and was stored at −40°C until required for batch genotyping. Plasma was prepared for quantifying routine biological profiles.Genotypes of six examined polymorphisms were determined with the ligase detection reaction (LDR) method as previously described The accuracy of LDR method was tested in 70 randomly selected DNA samples (∼5%) which were genotyped again for quality control and were found to have complete concordance.2 test where appropriate. The Hardy-Weinberg equilibrium was tested at each locus on a contingency table of observed-versus-predicted genotype frequencies using a Fisher’s exact test. A two-tailed P value of less than 5% was considered statistically significant, whereas a value of Pb  was considered significant after the Bonferroni correction.Continuous and categorical variables were compared between the two groups by the unpaired Student’s t-test and the χFor each polymorphism, we attempted three different modes of inheritance in a Logistic regression analysis, that is, additive, dominant and recessive modes after adjusting for age, gender, BMI, systolic blood pressure and fasting glucose. Statistical analyses described above were completed with the STATA software for Windows (version 11.0) . Study power was estimated by the Power and Sample Size Calculations (PS) software (v3.0.7).http://www.r-project.org).Considering that six examined polymorphisms are located on three different chromosomes, we examined their joint effect by estimating the frequencies of allele combinations by the haplo.em program. This program computes the maximum likelihood estimates of allele combination probabilities using the progressive insertion algorithm which progressively inserts batches of loci into allele combinations of growing lengths. Only allele combination with frequency of at least 3% in all study subjects was summarized. Adjusted odds ratio (OR) and its 95% confidence interval (95% CI) for each allele combination were computed by the haplo.cc and haplo.glm programs, based on a generalized linear model http://www.epistasis.org) To further examine the interaction of examined polymorphisms, we resorted to an open-source multifactor dimensionality reduction (MDR) software , even after the Bonferroni correction : Pb = 0.0083). The power to reject the null hypothesis of no difference in significant allele frequencies for rs2073478 and rs671polymorphisms between patients and controls was 88.1% and 87.0%, respectively. No significance was identified for the other four polymorphisms.The genotype distributions and allele frequencies of six examined polymorphisms between the CAD group and the control group are provided in ALDH1b1 rs2073478, the odds of having CAD was increased by 29%  under an additive mode and 42%  under a dominant mode, even with a Bonferroni corrected alpha of 0.05/6. With regard to ALDH2 rs671, the odds of CAD was only significant under additive  and recessive  modes after the Bonferroni correction.The risk prediction of six examined polymorphisms for CAD was examined under three genetic modes of inheritance . Likewisb = 0.05/11). There was no observable significance for the other allele combinations between the two groups.After assigning the most common allele combination as a reference, allele combination A-C-C-T-C-A, which simultaneously possessed the risk alleles of rs2073478 and rs671 polymorphisms, was associated with a 1.80-fold greater risk of CAD, whereas this association was nonsignificant after the Bonferroni correction  in CAD patients and plasma TC (Simulated P = 0.031) in controls .Interaction analysis of six examined polymorphism by MDR software is summarized in To test the validity of MDR method, we further conducted a classical Logistic analysis that incorporated the produce of two polymorphisms in the best model and confounding factors including age, gender, BMI, systolic blood pressure and fasting glucose. The interaction of these two polymorphisms was found to be associated with a 1.16-fold  increased risk of CAD under an additive mode.ALDH1b1 and ALDH2 might not only play a leading role in the prediction of CAD susceptibility, but also interact synergistically to enhance the power of risk prediction. Our findings provide convincing evidence for the potential involvement of alcohol metabolism relevant genes in the pathogenesis of CAD.The aim of this study was to examine the association between six polymorphisms of four alcohol metabolism relevant genes and CAD risk in northeastern Han Chinese. It is worth noting that genetic defects of ALDH2 rs671 polymorphism in susceptibility to CAD and myocardial infarction, with the rs671-A allele associating with an increased risk of at least 1.2 and 1.32 Three recent meta-analyses consistently supported a contributory role of ALDH2 rs671 polymorphism to CAD, we additionally identified a synergistic interaction between rs671 and another individually significant polymorphism rs2073478 in ALDH1b1. On one hand, this interaction was reflected in our allele combination analysis, as the combination simultaneously possessing the two ‘risk’ alleles of these two polymorphisms was associated with a greater risk of CAD, which was further observed to be mediated via regulating lipid profiles by our allele combination-phenotype analysis. In fact, previous studies have shown that the mechanisms of alcohol involved in CAD might be explained by an effect on increasing plasma HDL-C level and decreasing platelet aggregation ALDH2 rs671 and ALDH1b1 rs2073478 polymorphisms was identified as the overall best synergistic model by using a promising data-mining analytical method, MDR, which reinforced the results of both individual and allele combination analyses. This method is nonparametric and genetic model-free nature in design Besides the validation of significant susceptibility of Several specific strengths and limitations of this study merit adequate consideration. A major advantage was that both CAD patients and controls were angiographically confirmed, which can minimize the misclassification of study subjects as far as possible. A further merit was the selection of hypertensive patients as a background population, which can remove the confounding impact of hypertension, considering that hypertension is an independent predisposing factor for CAD ALDH1b1 and ALDH2 and the development of CAD in northeastern Han Chinese. For practical reasons, large, well-designed longitudinal studies attempting to shed light on gene-to-gene and gene-to-environment interactions, as well as studies striving to provide biological or clinical implications of alcohol metabolism relevant genes, are needed in future investigations.To conclude, our findings provide clear evidence for the individual and interactive associations between genetic defects of


IRGM) gene, and susceptibility to Crohn’s disease (CD). The PubMed, CISCOM, CINAHL, Web of Science, Google Scholar, EBSCO, Cochrane Library and CBM databases were investigated from database inception through to October 1, 2013 without the application of any language restrictions. The meta-analysis was performed using STATA 12.0 software and the relative risk (RR) with a 95% confidence interval (CI) was calculated. Seven case-control studies were included with a total of 3,093 CD patients and 3,227 healthy control subjects. The results of the meta-analysis revealed that the IRGM rs13361189 polymorphism correlates with an increased risk of CD . A subgroup analysis conducted using a genotyping method indicated that the IRGM rs13361189 polymorphism was correlated with an increased risk of CD in the TaqMan®  and the polymerase chain reaction-restriction fragment length polymorphism subgroups . However, no correlation was observed in the direct sequencing subgroup (P>0.05). Further subgroup analysis by sample size demonstrated significant correlations between the IRGM rs13361189 polymorphism and an increased risk of CD in the large sample-size subgroup . However, no correlation was identified between the IRGM rs13361189 polymorphism and CD risk in the small sample-size subgroup (P>0.05). The present meta-analysis indicated that the IRGM rs13361189 polymorphism may contribute to susceptibility to CD. Thus, IRGM rs13361189 polymorphism may be a potential biomarker for the early diagnosis of CD.The aim of the present meta-analysis was to evaluate the correlation between a common polymorphism, rs13361189 C>T in the immunity-related GTPase M ( IRGM) gene is associated with an increased CD risk (Crohn’s disease (CD), also identical to Crohn syndrome or regional enteritis, refers to one form of inflammatory bowel disease that may affect any part of the gastrointestinal tract between the mouth and the anus, resulting in various symptoms . In rece CD risk ,7.IRGM gene is located on chromosome 5q33.1 and contains five exons  and (‘Crohn’s disease’ or ‘CD’) and (‘human immunity-related GTPase M’ or ‘IRGM’). In addition, a manual search was performed to obtain other potential articles.IRGM rs13361189 polymorphism and susceptibility to CD; iii) the patients conformed to the diagnostic criteria of CD; and iv) the study provided sufficient information regarding the frequency of the IRGM rs13361189 polymorphism. Studies that did not meet the inclusion criteria were excluded. The most recent or the largest sample-size study was included when the authors published several studies regarding the same subject matter.In the present meta-analysis, studies were included when the following criteria were met: i) The study design was a clinical cohort or case-control study; ii) the study concerned the correlation between the Using a standardized form, the relevant data were systematically extracted from all the included studies by two researchers. The standardized form included the following items: Language of publication, publication year of article, first author’s surname, geographical location, design of the study, sample size, country of origin of the subjects, allele frequencies, source of the samples, genotyping method of the SNPs and evidence of Hardy-Weinberg equilibrium (HWE) in the healthy control subjects.The methodological quality of the included studies was evaluated according to the Newcastle-Ottawa Scale (NOS) . The NOS2 test were used to evaluate potential heterogeneity between the studies . The relative risk (RR) and the 95% confidence intervals (CI) were estimated. The Z test was used to estimate the statistical significance of the RRs, and the power calculations were conducted using power and sample size calculations . Cochran studies . When thion bias .® method was conducted in five studies and the other two studies used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing methods, respectively. The genotype frequencies of the controls were all in HWE (P>0.05) and the NOS scores of the included studies were >5 . The study characteristics and methodological quality are summarized in A total of 107 articles were initially identified using the aforementioned keywords. The titles and abstracts of the articles were reviewed and 53 articles were subsequently excluded; the full texts and data integrity for the remaining articles were reviewed and a further 47 studies were excluded. Finally, seven case-control studies were included in the present meta-analysis –20,25–27IRGM rs13361189 polymorphism correlates with an increased risk of CD  and PCR-RFLP subgroups , but not in the direct sequencing subgroup . However, no correlation was identified between the IRGM rs13361189 polymorphism and CD risk in the small sample-size subgroup (P>0.05).The random effects model was conducted due to the significant heterogeneity that existed between the studies. The present meta-analysis results revealed that the  P>0.05; . FurtherThe results of the sensitivity analysis indicated that no single study influenced the overall pooled odds ratio . UnivariIRGM genetic polymorphisms that influence the normal expression of IRGM have been indicated to be associated with an increased risk of CD (IRGM is responsible for the innate immune response via regulation of autophagy formation in response to intracellular pathogens . Cell hosk of CD ,16.IRGM rs13361189 polymorphism and susceptibility to CD was evaluated. Seven independent case-control studies were included with a total of 3,093 CD patients and 3,227 healthy control subjects. The meta-analysis results demonstrated that the IRGM rs13361189 polymorphism correlates with an increased risk of CD, indicating that rs13361189 may be a causative factor for the incidence of CD. Although the exact function of the IRGM genetic polymorphism in CD is not fully understood, a potential explanation is that the IRGM genetic polymorphism may alter the function of IRGM, leading to the invasion of bacteria in vivo, resulting in tissue damage and chronic intestinal inflammation (IRGM rs13361189 polymorphism and an increased risk of CD in the TaqMan® and the PCR-RFLP subgroups. However, no correlation was identified in the direct sequencing subgroup; this result was unreliable due to the small sample size. Further subgroup analysis by sample size showed a significant correlation between the IRGM rs13361189 polymorphism and an increased risk of CD in the subgroup with a large sample size. However, no correlation between the IRGM rs13361189 polymorphism and CD risk was identified in the subgroup with a small sample size. These results indicated that sample size may be a potential source of heterogeneity. The findings were predominantly consistent with previous studies, which demonstrated that the IRGM rs13361189 polymorphism may be strongly associated with the development and progression of CD, indicating that the IRGM rs13361189 polymorphism may be utilized as a biomarker for the early diagnosis of CD.In the present meta-analysis, the correlation between the IRGM rs13361189 polymorphism and CD risk due to the relatively small sample size. Secondly, meta-analysis is a type of retrospective study that may lead to subject selection bias, thereby affecting the reliability of the results. Thirdly, the present meta-analysis failed to obtain the original data from the included studies, which may have further limited the evaluation of the potential roles of the IRGM genetic polymorphism in the development of CD. Furthermore, the inclusion criteria of the cases and controls were not well defined in all the included studies, which may have influenced the results.However, the present meta-analysis had certain limitations. Firstly, the results may not provide sufficient statistical power to estimate the correlations between the IRGM rs13361189 polymorphism may contribute to susceptibility to CD. Thus, the IRGM rs13361189 polymorphism may be a potential biomarker for the early diagnosis of CD. However, due to the abovementioned limitations, additional detailed studies are required to confirm these findings.In conclusion, the present meta-analysis indicated that the


Aims: To investigate the association between the methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) polymorphism rs 2236225 (c.1958G>A) and susceptibility to non-syndromic cleft of the lip and/or palate (NSCL/P).Methods: An extensive literature review has been conducted using PubMed, Web of Science, Cochrane Library, Google Scholar, the China National Knowledge Infrastructure (CNKI), and Wanfang Database for eligible researches. The terms for searching were “cleft lip OR cleft palate OR CLP OR CL/P OR oral facial cleft OR OFC” AND “methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1 OR methenyltetrahydrofolate cyclohydrolase formyltetrahydrofolate synthetase OR MTHFD1 OR MTHFD”. Two independent researchers screened, evaluated and extracted the data of included studies. The pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated by random effects model under five gene models. Subgroup, sensitivity analysis and publication bias were also assessed.Results: Ten case-control studies have been included in the systematic review and eight studies have been considered for the meta-analysis. Overall, the MTHFD1 polymorphism rs2236225 and the risk of NSCL/P showed pooled OR (95% CI) of 1.02 (0.86-1.21) under allelic model. A higher degree of heterogeneity was observed in Asian countries (I2 = 75.6%) compared to non-Asian countries (I2 = 48.9%). Similar consequence appeared in the subgroup of children (I2 = 78.6%) compared with that of mothers (I2 = 0.0%). There was no significant difference in the publication bias by the Begg’s funnel plot (P = 0.711) and Egger’s regression test (P = 0.746).Conclusion: Our assessment suggested there was no significant association between the MTHFD1 polymorphism rs 2236225 (c.1958G>A) and the susceptibility to NSCL/P. Further investigations using a large sample size and a more advanced technique should be adopted to reach a more precise conclusion in the future. Non-syndromic CL/P, accounting for about 70% of CL/P, is considered closely related to genetic and environmental factors5. Recent studies suggested that using folic acid could reduce the rates of oral clefts7 and single nucleotide polymorphisms of some genes such as MTHFR9, MTR40 and MTRR involved in the metabolism of folic acid have been associated to high risk of NSCL/P9. Methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), a key gene associated with three sequential enzymatic reactions in the metabolism of folic acid, might play a potential role in the risk of NSCL/P, especially the polymorphism rs2236225 (c.1958G>A)10. Indeed, different observations that linked the polymorphism rs2236225 to the risk of NSCL/P have been reported12. The suggestion of a link between rs2236225 polymorphism and susceptibility to NSCL/P might be result of the limitations in sample size, different ethnic populations and other environmental factors. Therefore, we conducted a systematic review and meta-analysis of eligible case-control studies to reveal a more precise connection between theMTHFD1 polymorphism rs2236225 and the risk of NSCL/P.Cleft of the lip and/or palate (CL/P) is one of the most common facial malformations13 was performed in PubMed, Web of Science, Cochrane Library, Google Scholar, China National Knowledge Infrastructure (CNKI) and WanFang Database. The final update was made on April 5th, 2015. In line with our knowledge background, the Medical Subject Headings (MESH) terms in PubMed and the known aliases of the genes of interests in the National Center of Biotechnology Information (NCBI), the following terms were used for searching: “cleft lip OR cleft palate OR CLP OR CL/P OR oral facial cleft OR OFC” AND “methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1 OR methenyltetrahydrofolate cyclohydrolase formyltetrahydrofolate synthetase ORMTHFD1 OR MTHFD”, which were slightly adjusted to optimize search results  focusing on humans, (3) case-control studies. Exclusion criteria were: (1) no association between NSCL/P and MTFHD1, (2) not focusing on humans but animal models orin vitro studies, (3) duplication of previous researches, (4) not original literature such as reviews, meta-analyses, comments and editorials.Researches included in our systematic review and meta-analysis meet the following criteria: (1) evaluating the association between the NSCL/P andData from eligible studies were extracted by two independent researchers (Huaxiang Zhao and Mengqi Zhang) in accordance with the inclusion and exclusion criteria. In case of any discrepancies, the third chief author (Feng Chen) would make a further investigation or bring it into a group-discussion. A special table was used for collecting information from the selected articles and the following entries were recorded: authors (year), country, location of geography, subjects, methods for genotyping, sample size of cases/controls, descriptions of samples rolled in the study, P for HWE (Hardy-Weinberg equilibrium) of control group, whether included in the meta-analysis or not.16 was carried on included studies  and 95% confidence intervals (CIs) were calculated to estimate the association between the susceptibility to NSCL/P andMTHFD1. Five genetic models were used in the process of pooling the OR and 95% CIs: allelic comparison (A versus G), heterozygote model (AG versus GG), homozygote model (AA versus GG), dominant model (AA + AG versus GG), recessive model (AA versus AG + GG). The significance of the pooled effects was determined by Z-test with P value less than 0.05. The Q-statistic and the I2 test were used to evaluated; P < 0.05 in Q statistic or I2 > 50%19, would indicate a significant heterogeneity. When P > 0.05 in Q statistic or I2 < 50%, the fixed pooling model (Mantel-Haenszel) was conducted; if not, the random pooling model (M-H heterogeneity) was used. We also carried subgroup analyses in which different subjects (mothers or children), location of geography (non-Asian countries or Asian countries) were considered potential source of heterogeneity. A sensitivity analysis was conducted by omitting each study in turn to evaluate the single study’s influence on the overall estimation. We used Begg’s funnel plot and Egger’s linear regression test to find out the publication bias of the included studies22. The studies with disequilibrium of HWE among control group were added into a supplementary meta-analysis as described previously23. Meanwhile, as for the studies included but not carried into the meta-analysis, to achieve a qualitative analysis we adopted a method described by others24. Results were considered significant when P < 0.05. Stata 12.0  was used for the analysis.The PRISMA checklist  was used26, one no relation to MTFHD127, and the other two presented data previously published29. Finally, 10 studies that met the criteria were included in the systematic review . After being imported into EndNote X6 software , a screening process was conducted among 102 articles– that is, duplicates were removed using the ‘Discard Duplicates’ function as well as by handwork. Following paper selection by two independent researchers, 15 studies were then thoroughly reviewed. Of these, five studies were excluded, among which two had no control groups review 10–12,Eventually, all 10 studies containing 6216 samples (2959 cases and 3257 controls) were analyzed in our review. The characteristics of every study can be seen inMTHFD1 polymorphism rs2236225 (c.1958G>A) and NSCL/P susceptibility was analyzed through a meta-analysis and qualitative analysis. In the meta-analysis, since significant heterogeneity had been identified by Q-test and I2 statistic in every genetic model, the random effect models were used. Overall, a significant association was not found in any genetic model  or non-Asian population . However, a higher degree of heterogeneity was observed in the Asian countries compared to non-Asian countries (H = 0.001) than in the mothers’ group , while no significant difference was observed in both groups . It turned out that there was no significant difference between Asian  and NSCL/P risk under allelic model  to estimate the publication bias. Our results indicate that there is no significant publication bias both in the symmetry of Begg’s funnel plot  have been reported in different articles12.CL/P is one of the most common facial malformations, affecting approximately 1.7/1000 people around the world with ethnic and geographic variationMTHFD1 polymorphisms rs 2236225 (c.1958G>A). After the over-all analysis we concluded the comprehensive effect. All the eligible studies of meta-analysis and qualitative analysis showed no significant association ofMTHFD1 rs2236225 to the risk of NSCL/P, whether in the whole analysis of five model  or in the subgroup of subjects (mothers or children) and the location of geography (non-Asian countries or Asian countries). Meanwhile, high heterogeneity was observed, which might be the reason for the genetic drift and natural selection among different ethnic groups42. Also, small sample size of different studies might be a possible reason for the disparate results. Our findings suggest that theMTHFD1 polymorphism rs2236225 (c.1958G>A) might not be an appropriate biomarker in predicting the susceptibility of an individual to NSCL/P.In this systematic review, 10 independent case-control studies were included  containing 6216 samples (2959 cases and 3257 controls). In all of the included 8 studies for meta-analysis, 7 did not show significant difference between the case and control groups. 1 study reported that the case group showed closer relationship with43. However, a bigger size of cohort study cannot be conducted easily because of the relatively low morbidity44. Secondly, only 10 studies were included in our review, a small sample size that might not provide sufficient evidence to estimate the connections between theMTHFD1 polymorphisms and the risk of NSCL/P. Thirdly, the publication bias cannot be effectively analyzed because of the limited amount of included study.Some limitations of this systematic review and meta-analysis should be noted. Firstly, the choice of retrospective studies has its own limitations, as we may encounter selection bias and influence the results of our analysis45. Although no correlation was observed between MTFHD1 polymorphism rs2236225 (c.1958G>A) and the risk of NSCL/P, in view of MTFHD1 gene’s key role in folic acid metabolism, we cannot draw a definite conclusion that there is no association between MTFHD1 and NSCL/P’s susceptibility. The use of larger sample size studies, different techniques and considering gene-gene or gene-environment interactions should be explored in future investigations. What is more, the gene samples from mother were too scarce to be representative and to explain our results. We do recommend more samples from parents in the future studies, which is significant for the early stage diagnose, as the current technology can only diagnose CLP in the midterm even later in the pregnancy.NSCL/P is also associated with gene-gene and gene-environment interactions The current version of this report has properly included all of my suggestions and comments. I think that now this version was really improved the message for the readers.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. All of the gene acronyms may be written italics.The title says "Is MTHFD1 polymorphisms..." but it refers to only one SNP.The Materials and Method section includes the quality analysis of each paper included in this meta-analysis, but Results section did not mentioned anything about this analysis.The publication bias analysis when < 10 articles is not statistically resolved (see Egers's paper), so for this meta-analysis it is necessary at least a comment about this issue.The first two paragraph of the Discussion section are almost the same as the Introduction.I think that the Discussion could include a comment about maternal genotype effects in order to explain the negative results of this analysis.In general terms, this article contributes to unraveling the complex genetic architecture of NSCL/P. This type of systematic reviews are always relevant due to the fact that they pooled several singles trials, and therefore, the sample sizes have an important increase. However, this article needs some modifications that avoid to be published in its current version:I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. We have corrected all the inappropriate format of gene acronyms;Our title says “Is MTHFD1 polymorphisms rs 2236225 (c.1958G>A)…”, which refers to a specific SNP in accordance with the content;The traditional meta-analysis focuses on the clinical RCTs, which aims to reveal the relevance between specific interruption and clinical effects. A complete assessment standard for the included RCT reports has been widely accepted and used. While our study material is totally different from RCTs thus there is no clear assessment standard to refer. So we do not discuss the quality analysis. But in order to provide the readers an assessment standard we provide the tables 2 in supplementary materials for reference.We agree that the usual method to evaluate publication bias is not suitable for our study because of the limited amount, which reduces the reliability of our conclusion. We have declared that in the discussion of our updated version.Actually the Discussion is an overview of the article, which includes and further explains the content above. While in avoidance of repetition we modified and simplified the first and second paragraph of the Discussion.Two of our included studies only analyzed the maternal genotype, one study reported the mother and children genotype and three took samples from children and their parents. The gene samples from mother were too scarce to be representative and to explain our results. We do recommend more samples from parents in the future studies, which is significant for the early stage diagnose, as the current technology can only diagnose CLP in the midterm even later in the pregnancy.Thank you so much for your precious advice. We have studied your comments carefully and revised the manuscript. The point to point responds are listed as following: Non-syndromic cleft of the lip and/or palate (NSCL/P) is considered closely related to genetic and environmental factors. As a key gene in the metabolism of folic acid which is associated to high risk of NSCL/P, methylenetetrahydrofolate dehydrogenase (MTHFD1) polymorphisms rs 2237225 (c. 1958G>A) may be associated with the susceptibility of NSCL/P. However, controversial conclusions on this association have been reported by different groups. This paper conducted a systematic review and meta-analysis of eligible case-control studies which is necessary before we go forward to larger sample size studies.Page 6, Figure 1, Eligibility section, the number of full-text articles excluded with reasons should be 5.et al., 2015Meng) or other diseases ?The lack of folic acid will result in many health problems such as neural tube defects, macrocytic anemia, mental depress and so on, not only NSCL/P. MTHFD1 is important in the metabolism of folic acid. Why is it suggested that MTHFD1 polymorphisms may be associated with the susceptibility of NSCL/P, but not neural tube defects  have been reported in different articles. A brief description about the controversial results and their conclusions will make the discussion more interesting.MTHFR, MTR, AND MTRR which are involved in the metabolism of folic acid are reported to be associated with high risk of NSCL/P. Why MTHFD1 which is also involved in the metabolism of folic acid shows no significant association with susceptibility to NSCL/P? It’s due to the sample size or the limit of technique, or it is the truth? A brief discussion on this will be interesting.This paper is scientifically sound, clear and well-organized. However, these following revisions may make it more interesting.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. We have corrected the error, thank you;Neural tube defects and NSCL/P is similar in the origin of development, while the different relationship with MTHFD1 may suggest the different pathogenesis. Maybe each part of organ has a specific different folic acid metabolic pathway in their development.We are so glad to follow your advice. In all of the included 8 studies, 7 did not show significant difference between the case and control groups. 1 study reported the case group showed closer relationship with MTHFD1 polymorphisms rs 2236225 (c.1958G>A). A brief description of this controversy is also included in this article.All 10 studies containing 6216 samples (2959 cases and 3257 controls) were analyzed in our article. Limited to the size of simple, our result cannot give a certain conclusion about the relationship of MTHFD1 and NSCL/P and won’t deny the possibility of an actual relationship. The heterogeneity exists in the research method, sample source area and maternal or children genotypes. The incident rate and clinical manifestation differ in various areas. Different research method would lead to diverse accuracy even controversial conclusion. Thus we are still not sure about the association between MTHFD1 and NSCL/P and further exploration is needed. We also discussed this matter in our article.Thank you. We have studied your valuable comments and revised the manuscript according to your suggestions. The point to point responds are listed as following:


LOX) with keratoconus. However, the results remained inconclusive and great heterogeneity might exist across populations.Several case-control studies have been performed to examine the association of genetic variants in lysyl oxidase  and 95% confidence intervals (CI) of each single nucleotide polymorphism (SNP) were estimated with fixed effects model when P = 1.43E-08) and 0.77 , respectively. In contrast, our study lacked sufficient evidences to support the association of rs1800449/rs2288393 with keratoconus across populations.A total of four studies including 1,467 keratoconus cases and 4,490 controls were involved in this meta-analysis. SNPs rs2956540 and rs10519694 showed significant association with keratoconus, with ORs of 0.71 (95% CI: 0.63–0.80, LOX variants, rs2956540 and rs10519694, may affect individual susceptibility to keratoconus, while distinct heterogeneity existed within this locus. Larger-scale and multi-ethnic genetic studies on keratoconus are required to further validate the results.This meta-analysis suggested that two  Keratoconus is a bilateral, non-inflammatory corneal ectasia characterized by progressive thinning and conical protrusion of the cornea, which eventually leads to mild or markedly impaired vision due to high myopia and irregular astigmatism. The approximated incidence of keratoconus is 1 in 2,000 individuals in the general population and the estimated prevalence is reported to be 54.5 per 100,000 [VSX1[SOD1[TGFBI[COL4A1-4, COL5A1)[The etiology of keratoconus is far from understood, with environmental, behavioral, and genetic factors all contributing to the disease. However, the much higher risk of keratoconus in first-degree relatives compared with the general population, and the high disease concordance in monozygotic twins, indicate a strong genetic component to keratoconus –7. WhileVSX1, SOD1[10OD1[TGFBI, and mul, COL5A1), 13. How, COL5A1).LOX) as a potential susceptibility gene for keratoconus in American Caucasians [LOX showed strong association with the disease in that GWAS study, although their overall P-values did not reach genome-wide significance in the combined dataset. SNPs rs1800449 and rs2288393, which are in absolute linkage disequilibrium , revealed marginal association with the disease in case/control cohort from the same study. Later, replication studies in Czech Caucasians [LOX to keratoconus susceptibility, the results were inconclusive and great heterogeneity might exist across populations. Moreover, individual study might be restricted by sample size and other limitations of study design, while meta-analysis might benefit in overcoming the limitations by increasing the sample size, which has been widely applied in genetic association studies. Therefore, the aim of the current study was designed to clarify the association between LOX variants and keratoconus susceptibility.Genome-wide association studies (GWAS) have also been performed in keratoconus, albeit in relatively small number of samples. In 2012 a GWAS project consisting of 526 keratoconus cases and 3,842 controls, together with 70 keratoconus families with a total of 146 patients and 161 unaffected family members identified lysyl oxidase , and Weipu database , with the following MeSH terms and free words: “LOX”, “lysyl oxidase”, “polymorphism”, “SNP”, “variant(s)”, “single nucleotide polymorphism” and “keratoconus”. Studies published in English and Chinese were all included in this meta-analysis, and the reference lists of all the relevant studies, including original articles, reviews were carefully screened. The inclusion criteria applied in the review process was shown as following: (1) case-control studies that investigating the association of LOX variants with keratoconus. Familial studies were excluded due to the relationships between individuals biasing the allele counting analysis methods employed for meta-analysis; (2) subjects from case and control groups should come from the same geographically and temporally defined population, and control subjects were free of keratoconus or any form of ocular diseases; (3) Sufficient data for estimating odds ratio (OR) with 95% confidence interval (CI). Data from non-overlapped sample cohorts from the same study were considered as different sample collections as introduced previously [All studies investigating the association of variants in eviously .Two reviewers independently assessed all potentially relevant studies with the inclusion criteria, cross-checked, discussed all conflict, and reached consensus on all items. The following information was extracted from each study: author, year of publication, population ethnicity, age and gender information of cases and controls, the result of Hardy-Weinberg equilibrium (HWE) test in controls, numbers of cases and controls, and available allele and/or genotype counts or frequencies of each SNP. The allele or genotype counts were calculated from the frequencies, rounding to the closest integer, in those studies where the counts were not presented –16.I2 test. OR and 95% CI for the minor allele were calculated with fixed effects model when I2<50% or random effects model when I2>50% [LOX and keratoconus was evaluated by the Z-test. The P values were transformed from the Z scores and a pooled P value less than 0.05 was considered as statistically significant. Publication bias was evaluated using a funnel plot, in which the standard error of log (OR) of each study was plotted against its OR. An asymmetric plot suggested possible publication bias. Funnel plot asymmetry was further evaluated by the method of Egger’s test [P<0.05, publication bias was assumed to exist. The LD values between SNPs in different populations were extracted from SNAP website based on the data from 1000 Genome Project[https://www.broadinstitute.org/mpg/snap/).SNPs reported in two or more studies were conducted for meta-analysis. The heterogeneity among studies was tested with the  I2>50% . The star’s test  or Horbor’s test . When the Project  was detected, which might be explained by the differences between Czech Caucasians and American Caucasians. The random effects model was adopted here and this SNP was also significantly associated with keratoconus . Since the genotype counts/frequency data was not available in the studies of Bykhovskaya et al. and Dudakova et al., meta-analyses on the genotypic level were not performed in the current study.Four SNPs  in Publication bias were qualitatively assessed by funnel plot and quantitatively assessed by Egger’s test or Horbold-Egger’s test. None of the test detected obvious evidence of publication bias .et al. suggested that two SNPs in LOX gene, rs2956540 and rs10519694 contributed to keratoconus susceptibility, although their overall P values did not reach genome-wide significance. After sequencing of LOX gene in affected individuals and testing of transcribed LOX polymorphisms in relatively small case-control and family cohorts, they further indicated the additional marginal effect of rs1800449/rs2288393 to the overall association signal in the LOX gene. These SNPs have been subsequently investigated in different ethnic populations whilst the results were inconsistent and variable. Therefore, in order to provide a reliable evaluation of the association between SNPs in LOX and keratoconus susceptibility, we performed meta-analysis, which involved the largest sample size to date with a total of 1,467 keratoconus cases and 4,490 controls. A strong association of LOX variant rs2956540 with keratoconus was identified in the combined dataset of Caucasians and Chinese cohorts (P = 1.43E-08) and there was no heterogeneity (I2 = 0). Our data also suggested the significant association of rs10519694 with keratoconus (P = 0.026) in Caucasians, with moderate heterogeneity (I2 = 53%) probably due to the underlying population differences. This SNP has not been replicated in other ethnicities, and its contribution to keratoconus susceptibility in non-Caucasians requires further investigation. In contrast, our study lacked sufficient evidences to support the association of rs1800449/rs2288393 with keratoconus (P>0.01) across populations. Distinct heterogeneity has been observed across study populations (I2>50%).In a recent genome-wide association study, Bykhovskaya LOX in keratoconus, and this study identified a keratoconus-associated SNP that first reaching genome-wide significance at this locus. LOX encodes an extracellular copper enzyme that initiates the crosslinking of collagens and elastin. The formation of covalent bonds between collagen and elastin fibrils, which maintain the biomechanical properties of the cornea, is mediated by LOX and other four lysyl oxidase-like enzymes. It was demonstrated that changes in LOX distribution and its decreased activity might be potential reasons for the inadequate collagen cross-linking in keratoconus, which is a hallmark of this disease [LOX transcript was observed in corneal epithelia of keratoconus patients compared to healthy donors, and LOX activity in keratoconus tears was found to correlate with disease severity [LOX in the pathogenesis of keratoconus, and also implying the importance of deciphering the genetic code of LOX in contributing keratoconus susceptibility. Rs2956540, the most significant SNP at this locus showed remarkable consistency of disease association across populations, although its minor allele frequency was quite different among populations (http://www.genomatix.de/) that it can alter the binding sites of several transcription factors like PTX1, CMYB, and ISM1. Our study highlighted the importance of LOX locus to keratoconus susceptibility, while more efforts are required to get a comprehensive understanding on the detailed mechanisms.To our knowledge, this is the first meta-analysis report evaluating the published genetic studies on  disease . In addiseverity . All of ulations . SNP rs2r2 values of these SNPs in different ethnicities were shown in LOX variants to keratoconus susceptibility, currently we cannot perform further stratified analysis based on ethnicity, subclinical forms, or sample size. In addition, the contributions of these variants to keratoconus susceptibility were investigated in only a few populations, it should be of higher importance and generalizability if more details and various ethnicities in relation to keratoconus were reported, especially in Asians.Heterogeneity is a problem that might influence the results of our meta-analysis. Except for rs2956540, which showed highly consistent effects among the overall population analysis, significant heterogeneity was observed for the other three SNPs. The genetic effects of rs1800449 and rs2288393 in Iranian cohort were even opposite to that of in Caucasian populations. The four interrogated SNPs showed different allele frequency in the various populations shown in . We alsoSeveral other limitations of this meta-analysis should also be noted. Firstly, this meta-analysis was performed based on studies published in English and Chinese. It is possible that some relevant articles written by other languages may be missed out, which might introduce selection and publication bias, although we did not detect any significant bias by Egger’s test in the current study. Secondly, we failed to obtain original data from the studies included, making it unlikely to conduct a more precise analysis based on the adjustment of age, gender, or some other factors. Thirdly, only a small number of studies were eligible for inclusion in this meta-analysis. Although over 1,400 cases were involved in total, no single analysis included this many patients. Thus, the conclusions must be validated by further studies, and it should also be updated by including more upcoming reports.LOX variants, rs2956540 and rs10519694 were significantly associated with keratoconus. In the future, the two identified SNPs may be included in a genetic risk score with other associated SNPs for disease risk prediction. Future large-scale and multi-ethnic genetic studies on keratoconus are warranted, thereby ensuring a more comprehensive understanding of the genetic basis of keratoconus.In conclusion, the current study provided substantial evidences that two S1 Checklist(DOCX)Click here for additional data file.S1 Appendix(DOCX)Click here for additional data file.S2 Appendix(DOCX)Click here for additional data file.S1 Fig(DOCX)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.


Q-test and I2 statistic. Subgroup and sensitivity analyses were also conducted. Publication bias was estimated using Begg's and Egger's tests. A total of 17 case-controls studies were included. There was evidence for an association between the MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS. In the subgroup analysis, increased maternal risk for DS was found in Caucasians. Additionally, the polymorphic heterozygote MTHFD1 1958GA genotype was associated significantly with maternal risk for DS, when we limit the analysis by studies conformed to Hardy-Weinberg equilibrium. Finally, considering MTR c.2756A>G (rs1805087), TC2 c.776C>G (rs1801198), and CBS c.844ins68, no significant associations have been found, neither in the overall analyses nor in the stratified analyses by ethnicity. In conclusion, our meta-analysis suggested that the MTRR c.66A>G (rs1801394) polymorphism and MTHFD1 c.1958G>A (rs2236225) were associated with increased maternal risk for DS.Inconclusive results of the association between genetic polymorphisms involved in folate metabolism and maternal risk for Down syndrome (DS) have been reported. Therefore, this meta-analysis was conducted. We searched electronic databases through May, 2014, for eligible studies. Pooled odds ratios with 95% confidence intervals were used to assess the strength of the association, which was estimated by fixed or random effects models. Heterogeneity among studies was evaluated using  Down Syndrome (DS) is the phenotypic manifestation of trisomy of human chromosome 21 and is the most common genetic disorder of intellectual disability, characterized by dysmorphic features that are usual to almost all affected individuals, including craniofacial abnormalities and hypotonia  and, in In several studies, advanced maternal age at conception (35 years or older) has been associated with increased risk of DS births in various parts of the world . HoweverMethionine synthase (MTR), methionine synthase reductase (MTRR), transcobalamin 2 (TC2), cystathionine beta synthase (CBS), and methylenetetrahydrofolate dehydrogenase (MTHFD1) are very important enzymes involved in folate/homocysteine (Hcy) metabolism and play essential roles in synthesis and repair of DNA and methylation reactions . The metβ-synthase (CBS), an enzyme involved in the transsulfuration cycle, is responsible for metabolizing Hcy into cystathionine, a middle step in the synthesis of cysteine [MTHFD1), a trifunctional nicotinamide adenine dinucleotide phosphate-dependent cytoplasmic enzyme, catalyzes the sequential interconversion of tetrahydrofolate (THF) into the corresponding 10-formyl-THF, 5,10-methenyl-THF, and 5,10-methylene-THF [ de novo purine and pyrimidine biosynthesis and, thus, the synthesis of DNA [Cystathionine cysteine . Additiolene-THF , which ps of DNA .Genetic polymorphisms in key enzymes of folate metabolism have been identified in the alteration of the levels of folate and Hcy , in the  MTR c.2756A>G (rs1805087), MTRR c.66A>G (rs1801394), TC2 c.776C>G (rs1801198), CBS c.844ins68, and MTHFD1 c.1958G>A (rs2236225) polymorphisms, it is expected that these polymorphisms may be associated with the maternal DS risk and several studies have been carried out to determine this association. However, the results remain inconclusive. To explain these issues, we conducted a systematical review and a meta-analysis from all eligible studies, in order to provide more exact estimate of the association among MTR c.2756A>G (rs1805087), MTRR c.66A>G (rs1801394), TC2 c.776C>G (rs1801198), CBS c.844ins68, and MTHFD1 c.1958G>A (rs2236225) polymorphisms and the maternal risk for DS.Considering the functional effects of theA systematic review of literature was performed in PubMed, EMBASE, and Lilacs-Scielo databases . The keywords and subject terms used were as follows: (Down syndrome or trisomy 21) and . The reference lists of the retrieved studies were also screened in order to identify extra articles on this same topic. This research only included papers published in English, Spanish, or Portuguese. MTR c.2756A>G (rs1805087), MTRR c.66A>G (rs1801394), TC2 c.776C>G (rs1801198), CBS c.844ins68, or MTHFD1 c.1958G>A (rs2236225) polymorphisms and the maternal risk for DS in case mothers (DSM) and in a control group of mothers (CM); (c) DSM are considered mothers that gave birth to at least one child with DS, and the CM are mothers that have given birth to children without reported abnormalities; (d) studies with detailed genotype and allele frequencies of the DSM and CM or with sufficient data to calculate them; (e) for articles published by the same population resource or by the same research group, only the article with the largest sample size or most recent study was included in this meta-analysis. Studies with insufficient data, review articles, abstracts, editorials, comments, letters, case reports, and animal studies were excluded.The following inclusion criteria were used: (a) case-control studies design; (b) association studies that evaluated the association betweenThe data were extracted by two reviewers independently. Another reviewer was required in order to resolve the differences between them. The information extracted from each study includes the following: the first author's name, the publication's year, country, ethnicity, demography characteristics, genotyping method, genotype and allele frequencies, and the number of DSM and CM.A chi-square test was used to estimate the Hardy-Weinberg equilibrium (HWE) among the control subjects. The maternal risk was evaluated through the following comparisons: (1) allelic model ; (2) codominant models (heterozygous versus wild-type homozygous and polymorphic homozygous versus wild-type homozygous); (3) dominant model ; (4) recessive model . Subgroup analyses based on different ethnic populations (Caucasian and Brazilian) were also performed. Additionally, sensitivity analysis was used in order to examine the results stability by omitting one study at a time. Q-test [I2 statistic [The pooled OR was estimated using fixed-effects (FE)  and rand Q-test . The efftatistic , which rP ≤ 0.05 was considered statistically significant. Data analyses were performed using the Cochrane systematic review software Review Manager 5.2, BioEstat 5.3, and StatsDirect 1.9.15.Publication bias was examined by funnel plot method, in which the standard error of log (OR) of each study was plotted against its log (OR). The asymmetry in funnel plot is detected when publication bias is present. Funnel plot asymmetry was also determined by Begg's test  and Egge MTR c.2756A>G (rs1805087), MTRR c.66A>G (rs1801394), TC2 c.776C>G (rs1801198), CBS c.844ins68, and MTHFD1 c.1958G>A (rs2236225) meta-analysis . Finally, 17 case-control studies –41 with analysis .χ2 = 12.18, P = 0.0005) [χ2 = 70.5, P < 0.0001) [ MTRR c.66A>G (rs1801394), for Ribeiro  [χ2 = 4.23, P = 0.03) [ TC2 c.776C>G (rs1801198), and for Scala et al.  [ MTHFD1 c.1958G>A (rs2236225) polymorphism. A list of the details extracted from the studies included in the meta-analysis is provided in Studies were conducted in different ethnic populations: seven involved Caucasian , 36, 40, 0.0005)  and Ribe 0.0001)  in the M = 0.04)  and Liao = 0.03)  in the T = 0.05)  in the M MTR c.2756A>G (rs1805087) polymorphism on the maternal risk for DS based on 8 case-control studies [Firstly, we conducted meta-analysis of the effect of studies , 39, 40  MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS in all genetic models  in Asians because there was only one study included [A reanalysis was carried out in order to exclude the studies whose control groups were not in HWE , 32 to aincluded . For theincluded .Sensitivity analysis was also performed and consisted of the analysis of every subgroup obtained by the exclusion of one single study at a time. It focused on checking the effect of each individual study, since the exclusion of a given article may isolate the remaining subgroup from the article's particular effect. None individual study significantly induced the heterogeneity among studies observed in the MTRR c.66A>G polymorphism analyses (data not shown). Additionally, the results indicated that no single study influenced the pooled OR qualitatively (data not shown). It suggested that the results of this meta-analysis were stable. For the subgroup analysis by Caucasians, after eliminating the results of O'Leary et al.  and Scal TC2 c.776C>G (rs1801198) polymorphism and maternal risk for DS was found, neither for all populations nor for all populations in HWE  polymorphism and maternal risk for DS was investigated in 5 studies [ MTHFD1 c.1958G>A (rs2236225) polymorphism and maternal risk for DS when all populations are considered. However, the polymorphic heterozygote genotype GA was associated with significant maternal risk for DS , compared with the wild-type homozygote genotype GG when we limit the analysis by HWE  in all comparisons for all polymorphisms analyzed , MTRR c.66A>G (rs1801394), TC2 c.776C>G (rs1801198),βS C c.844ins68, and MTHFD1 c.1958G>A (rs2236225) polymorphisms and maternal risk for DS. Our results show significant association between MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS in almost all genetic models when the general population is considered. Additionally, after the population was stratified by ethnicity, an increasing maternal risk for DS was observed in Caucasians. Furthermore, our results suggest that the MTHFD1 1958GA genotype is associated with maternal risk for DS and also that there is no significant association among MTR c.2756A>G (rs1805087), TC2 c.776C>G (rs1801198), andβS C c.844ins68 polymorphisms and maternal risk for DS.The present meta-analysis consists of an evaluation ofFolate is part of the B vitamins family and it is crucial for the synthesis of SAM, the major cellular methyl donor for DNA methylation , 48. A c MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS. In our meta-analysis, we observed a significant association between the MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS in almost all genetic models, which corroborates with some of the previous case-control studies [ MTRR c.66A>G (rs1801394) polymorphism can lead to a decrease in the MTRR enzyme activity [Based on the above, several studies were conducted in order to elucidate the association between the studies , 26, 30.activity  and, sinactivity , 13, 14,The DNA methylation is very important to the regulation of gene expression, to genomic integrity, and also to stability and chromatin organization , 49, 50.Since moderate heterogeneity is present in our meta-analysis, we decided to perform a stratified analyses based on HWE and on ethnicity. However, subgroup and sensitivity analyses were not able to find the source of heterogeneity. In our meta-analysis, we tried to minimize the heterogeneity between studies by performing a very careful search strategy and study selection. To accomplish that, we used an explicit inclusion criteria and performed quality data extraction and analysis. Despite all these efforts, a significant interstudy heterogeneity was present in some of the comparisons. It is necessary to point out that heterogeneity among studies is frequently observed in meta-analysis studies that report genetic associations , and, in MTR c.2756A>G (rs1805087), TC2 c.776C>G (rs1801198), andβS C c.844ins68 polymorphisms did not contribute as an independent risk factor for DS. Our current data agrees with several previous performed case-control studies [ MTR c.2756A>G (rs1805087), TC2 c.776C>G (rs1801198), andβS C c.844ins68 polymorphisms and maternal risk for DS. First of all, the sample size of studies was relatively small. Secondly, risk factor may depend on genetic polymorphisms and potential gene-gene interaction. Several researchers showed that the polymorphisms are able to interact with each other and such interaction may modify their individual effects [In our meta-analysis, the evidence suggested that studies , 39, 41. effects , 37, 68. effects , 69. TC2 c.776C>G (rs1801198) and MTHFD1 c.1958G>A (rs2236225) polymorphisms and maternal risk for DS. Our result suggests that the presence of the MTHFD1 1958GA genotype might be associated with maternal risk for DS. Previous studies have supported that MTHFD1 c.1958G>A (rs2236225) polymorphism is able to reduce the activity and stability of the MTHFD1 enzyme and has been associated with an increased risk of neural tube defects [ MTHFR 677CT/TT and MTHFD 1958AA/GA [ MTHFD 1958AA/RFC1 80GG genotypes [ MTHFD1 c.1958G>A (rs2236225) meta-analysis was only 5, larger sample studies should be conducted in order to confirm this result.To the best of our knowledge, our study was the first meta-analysis to investigate the association among defects  and unex defects . Moreove958AA/GA  and MTHFenotypes  were sig MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS. Moreover, we were the first ones to conduct meta-analyses to evaluate the association among TC2 c.776C>G (rs1801198) and MTHFD1 c.1958G>A (rs2236225) polymorphisms and maternal risk for DS. Coppedè et al. [ MTRR c.66A>G (rs1801394) polymorphism and maternal risk for DS. However, we observed important results for such polymorphism: the heterozygote AG and polymorphic homozygote GG genotypes, dominant and recessive genetic models, were significantly associated with maternal risk for DS. Their study only comprised eleven case-control studies, while our study included two additional articles, which accounted for 20% of the total sample size. We also conducted stratified analyses by ethnicity, which was not made in the Amorim and Lima [To the best of our knowledge, there are three meta-analyses papers that reported the association between genetic polymorphisms involved in folate metabolism and maternal risk for DS , 72, 73.è et al.  conducteè et al.  article.There are still some limitations in this meta-analysis that need to be mentioned. Firstly, all included studies were performed as case-control studies, which prevent additional comments on a cause-effect relationship . Secondl MTRR c.66A>G (rs1801394) polymorphism was associated with maternal risk for DS, especially in Caucasians. Additionally, our result suggested that the MTHFD1 1958GA genotype could be associated with maternal risk for DS. Finally, the evidence demonstrated that MTR c.2756A>G (rs1805087), TC2 c.776C>G (rs1801198), andβS C c.844ins68 polymorphisms did not contribute as an independent risk factor of DS. Further larger and well-designed studies are required to confirm this conclusion; functional studies should also be conducted to fully understand the molecular mechanism of DS.In conclusion, our meta-analysis provided evidence that


Retinal vein occlusion (RVO) is a common retinal vascular disease and it is one of the most frequently reported causes of visual damage and blindness in the elderly. The current study investigated the potential association between antiphospholipid antibodies (APLA) and RVO risk by conducting a meta-analysis of case–control studies.st, 2014. Odds ratios (ORs) were used to evaluate the associations between APLA and the incidence of RVO. A random-effects model was obtained for the quantitative synthesis.A systematic literature search of Pubmed and Embase databases was conducted in August 1A total of 11 studies were included in this meta-analysis. A meta-analysis of all studies assessing the risk of RVO revealed that APLA was associated with a statistically increased risk of RVO incidence . The association between anticardiolipin antibodies (ACA) and the risk of RVO was significant . However, the association between lupus anticoagulants (LA) and risk of RVO was non-significant . No significant publication bias was found in the 11 selected studies.APLA was significantly associated with the risk of RVO. Advanced analyses showed that ACA rather than LA affected the risk of RVO. Additional well-designed and well-conducted epidemiological studies are required to further our understanding of the relationship between APLA and RVO risk. Retinal vein occlusion (RVO) is a common retinal vascular disease, and it is one of the most frequently reported causes of visual damage and blindness in the elderly . CentralIn general, RVO is a multifactorial disease, and the causes of RVO are quite complex . CardiovAntiphospholipid antibodies (APLA) include two main types, lupus anticoagulants (LA) and anticardiolipin antibodies (ACA). APLAs are acquired autoantibodies against phospholipid–protein complexes, which act as important autoantibodies in anti-phospholipid syndrome. Previous studies indicated that APLA is associated with pregnancy , thromboThis systematic review and meta-analysis was conducted following the guidelines of Meta-analysis of Observational Studies in Epidemiology , and it st, 2014 by two reviewers (WZ and YW) for all relevant studies on the association between APLA and RVO risk. The medical subject heading (MeSH) terms and key words used in the search included “retinal vein occlusion”, “retinal vein obstruction” combined with “antiphospholipid antibody”, “lupus anticoagulants” and “anticardiolipin antibody”. The title and abstract of studies identified in the search were reviewed by two authors independently (WZ and YW) to exclude studies that were not associated with the main outcome of this study. The full text of the remaining articles was examined for the final inclusion of the relevant studies. We also manually searched the reference lists for possible valuable studies. When incomplete information was available, attempts were made to contact the corresponding authors of the studies for additional information by writing an e-mail to the corresponding author.A systematic literature search of Pubmed and Embase databaseswas conducted independently in August 1A case-control study design was obtained for the relevant studies.The association between APLA  and RVO  risk was reported.We set the following criteria to identify the adequate studies included in this meta-analysis:No outcomes of interests were reported.Absence of raw data in a useful format.The following major reasons were used for the exclusion of studies:consonance was reached. Information obtained from each study included the first author, year of publication, types of APLA and RVO, and the numbers and characteristics of the participants in each study. The incidence data in different groups were extracted for the following meta-analysis.Data in each included study was extracted by two independent reviewers (WZ and YW) using the same standardized method. Any disagreements were settled by additional reviewers until a χ2 and I2 tests. A P value less than 0.10 or an I2 over 50% was considered suggestive of significant heterogeneity because tests for heterogeneity lack power. Once heterogeneity was noted in this study, the sources of heterogeneity were investigated using subgroup analyses by stratifying original estimates according to the study characteristics (as described above). Publication bias was qualitatively assessed using visual inspection of funnel plots of the logarithmic OR vs. their standard errors and quantitatively assessed using Begg and Egger tests [We used the random-effects model for quantitative synthesis because all of the included studies were observational in nature. Odds ratios (ORs) were used to evaluate associations between APLA and risk of RVO. The heterogeneity between studies was estimated using er tests ,26. AnalThe Pubmed search yielded 659 potentially relevant articles, and the EMBASE search yielded 641 articles. Twenty-four additional records were identified through a review of article references. A total of 1179 records of these articles were excluded based on the title and abstract review because they were clearly irrelevant to the objectives of this meta-analysis. In the detailed evaluation, after excluding 132 reviews, case reports and overlapped articles, 23 full-texts were obtained for full-text review. Finally, 11 studies were included in this meta-analysis –22 afterThe characteristics of these studies are shown in 2 = 0.00%, P = 0.909). Advanced subgroup analyses by locations showed that APLA was associated with an increased risk of RVO in Europe , America , Asia  and Africa . When the control group source was considered, significant associations between APLA and increased risk of RVO were detected in both healthy controls  and individuals without RVO . Furthermore, these results were significant in the studies with over 100 subjects  and less than 100 subjects . No significant heterogeneity was detected in any of the subgroup analyses . . There wanalyses .I2 = 0.00, P = 0.720). However, the association between LA and RVO risk was not significant . In general, the associations of APLA and both CRVO  and BRVO  were significant. When the associations of ACA and the two subtypes of RVO were considered, both ACA and CRVO risk  and ACA and BRVO  were significant. However, no significant association between LA and CRVO was detected . No correlation between LA and BRVO risk was found. Similarly, no significant heterogeneity was detected in any of the subgroup analyses in the above comparisons . The funnel plot is presented in This systemic review and meta-analysis summarized the current literature and contained 11 case-control studies that investigated the association between APLA and risk of RVO. The pooled estimate from the random-effects model provides remarkable evidence of a significant association between APLA and RVO risk. Advanced subgroup meta-analysis showed that APLA was associated with increased risks of both CRVO and BRVO. However, APLA subtype analyses showed that it is ACA rather than LA was a risk factor of RVO.APLA, including ACA and LA, are biomarkers of antiphospholipid antibody syndrome (APS). The association between APS and RVO has been studied in previous researches. For example, Ali et al. published a case report of BRVO and primary APS . TherefoAbuel-Asrar conducted a case-control study with 17 cases and 60 controls, and the results demonstrated that APLA was a risk factor of RVO in the younger group (less than 45 years old) . These rThis study reviewed the association between APLA and the risk of RVO. The main strength of this study is the detailed search strategy. The literature search included the MeSH and key word “risk factor”. It would be helpful to gain the possible inclusive data that are as complete as possible. Further advanced subgroup analyses would provide consummate knowledge on the issues of interests. Finally, the quantitative synthesis of data was considered clinically and statistically appropriate. This result would provide improved knowledge for clinical workers.However, there are several limitations of this study. First, all of the included studies were case-control designs. The lack of blinding of sampling and data analyses might produce several potential biases. Second, no publication bias was detected using three independent methods, but a potential existing publication bias should also be considered. Accordingly, more well-designed and well-conducted epidemiological studies are required to deepen our understanding on the relationship between APLA and RVO incidence.In conclusion, APLA, including ACA and LA, was significantly associated with the risk of RVO. The advanced analyses showed that ACA rather than LA affected on the risk of RVO. This study showed that APLA is a possible target for the detection of diagnostic and therapeutic interventions for RVO. Accordingly, additional well-designed and well-conducted epidemiological studies are required to deepen our understanding on the relationship between APLA and RVO risk.


ADRB2 and the susceptibility to MI and CAD.Recently, the rs1042713 G > A and rs1042714 C > G polymorphisms in the beta-2adrenergic receptor (ADRB2) gene were shown to be related to atherosclerosisdiseases. Therefore, we performed a systemic meta-analysis to determine whether thetwo functional polymorphisms are related to the risk of myocardial infarction (MI)and coronary artery disease (CAD). We identified published studies that are relevantto our topic of interest. Seven case-control studies, with a total of 6,843 subjects,were incorporated into the current meta-analysis. Our analysis showed a higherfrequency of rs1042713 G > A variant in patients with MI or CAD compared tohealthy controls. A similar result was also obtained with the rs1042714 C > Gvariant under both the allele and dominant models. Ethnicity-stratified subgroupanalysis suggested that the rs1042714 C > G variant correlated with an increasedrisk of the two diseases in both Asians and Caucasians, while rs1042713 G > A onlycontributes to the risk of two diseases in Asians. In the disease type-stratifiedsubgroups, the frequencies of both the rs1042713 G > A and rs1042714 C > Gvariants were higher in the cases than in the controls in both the MI and CADsubgroups. Collectively, our data contribute towards understanding the correlationbetween the rs1042713 G > A and rs1042714 C > G polymorphisms in Coronary artery disease (CAD), the most common category of heart disease, is the leadingcause of the hospital admissions, resulting in a high mortality in 2012 . GeneticADRB2 gene is located on the long arm of chromosome 5q31-q32.Structurally, it is an intronless gene that encodes a 413 amino acid protein product is a member of the superfamily of G-proteincoupled receptors (GPCRs) , utilizing selected commonkeywords for the ADRB2 gene, polymorphism, MI and CAD. The following keywords wereapplied in our literature search:  and for the exposure factors, as well as .No restriction was set on the language of the article. We further scanned thebibliographies of the relevant articles manually to identify additional relevantpapers. When the enrolled papers contained unclear or additional data in theiroriginal publications, the first authors were contacted and asked forclarification.To identify all pertinent papers that assessed the correlations of ADRB2 geneticpolymorphisms with the susceptibility for MI and CAD, we comprehensively searched thePubMed, Embase, Web of Science, Cochrane Library, CINAHL, CBM and CNKI databases and 95% confidence intervals (CI). We only extracted studies thatprovided the sample number and sufficient information about the ADRB2 variants, andwe excluded articles with incomplete, unavailable or inappropriate data, as well asthose studies in which MI and CAD were not confirmed by histopathologic examinations.In addition, only studies with a minimum of 100 cases were selected for themeta-analysis. All selected studies were consistent with Hardy-Weinberg equilibrium(HWE) in the control group. When 50% of the subjects in the extracted studiesoverlapped in more than two papers, we enrolled the most comprehensive study. Onlythe newest or most complete study was included when the same authors or grouppublished the extracted studies.To enroll high-quality articles into the current meta-analysis, we searchedcase-control studies on genotypic data for ADRB2 polymorphisms included in this meta-analysiswere TaqMan and polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) analyses, and the ADRB2 SNPs were rs1042714 C > G and rs1042713 G >A. All included studies, published between 2001 and 2010, were consistent with HWE. The baseline characteristics of the extracted studies arepresented in Initially, a total of 243 articles were retrieved. During study selection, the titlesand abstracts of the retrieved studies were screened based on the eligibilitycriteria detailed above, and 106 of the studies were excluded. Subsequently, the fulltexts of the remaining studies were carefully reviewed, and 103 studies failed tomeet the eligibility criteria. Any ambiguities or disagreements on the eligibilityfor our meta-analysis were discussed to reach a final consensus among severalreviewers. After stringent study selection, seven high-quality case-control studieswere enrolled in the final analysis  quality score systems toindependently assess the studies for quality  or fixed-effects model(Mantel-Haenszel method) of the individual study results, under the situation inwhich data from independent studies could be combined. The random-effect model wasapplied when there was heterogeneity among the studies, while the fixed-effects modelwas applied when there was no statistical heterogeneity. The subgroup meta-analyseswere also conducted according to ethnicity, disease type and genotyping method, so asto explore the potential effect modification, and the heterogeneity across theenrolled studies was evaluated with the Cochran's Q-statistic   to 100% . We utilized univariate meta-regression analysis and multivariatemeta-regression analysis to evaluate the possible sources of heterogeneity, andfurther multiple calibration tests were conducted using the Monte Carlo method.One-way sensitivity analysis was performed to evaluate whether the results could havebeen significantly affected. This was done through deleting a single study in ourmeta-analysis, one by one, to evaluate the influence of an individual data set on thepooled ORs. A funnel plot was constructed to assess the publication bias, which mightaffect the validity of the estimates. The symmetry of the funnel plot was furtherevaluated by Egger's linear regression test  estimate was chosen to enhancestability of the final value. To calculate the effect size for each study, thesummary ORs with the 95%CI were computed with the ion test . All tesAs shown in Q-test analysis revealed thepresence of heterogeneity . Therefore, we conducted subgroup analyses. Thesubgroup analysis based on ethnicity showed that the rs1042714 C > G polymorphismin the ADRB2 was positively correlated to the risk of MI and CAD in both Asians andCaucasians  , which was not the case for Caucasians (p = 0.125).Simultaneously, subgroup analyses by disease type revealed that the frequencies ofthe ADRB2 rs1042713 G > A and rs1042714 C > G polymorphismswere higher in the case groups than in the control groups in both the MI and CADsubgroups   instead of the TaqMan assay (p = 0.051) . The ethnicity,disease type and genotyping method subgroup analyses under the other four models are shownin We observed differences in the association of rs1042713 G > A and rs1042714 C >G polymorphisms with MI or CAD among different ethnicities, disease types andgenotyping methods, and further  < 0.05) .However < 0.05)  showed a < 0.05) . Afurth= 0.051) . This suA sensitivity analysis was performed to evaluate whether the present meta-analysiswas stable. Each study enrolled in our meta-analysis was individually evaluated forits effect on the pooled ORs. The overall statistical significance did not changewhen any single study was omitted. Therefore, the current meta-analysis data arerelatively stable and credible . ThegraADRB2 with the susceptibility to MI and CADbased on available data, we found that the rs1042713 and rs1042714 polymorphisms aresignificantly associated with the susceptibility to MI and CAD. With its seventransmembrane segments, ADRB2 belongs to the superfamily of G-protein-coupled adrenergicreceptors, and it is an important target of endogenous ligands, such as catecholamineand epinephrine, that mediate stress responses in humans and animals  andrs1042714 (Q27E) in the The ARDB2 signaling cascade is of relevance in cardiovascular and metabolic diseases,including obesity, and also in mental disorders and asthma .The development of cardiovascular diseases, such as MI and CAD, is thought to involveADRB2 through regulating the sympathetic and parasympathetic heart system influence oncontractility and heart rate . ADRB2 and ahigh risk of cardiovascular disease in the older age groups.The two ADRB2 gene have an intimate relationship with CAD and MI. Hence,the ADRB2 polymorphisms might be an important contributor tocardiovascular diseases, as well as an important genetic marker for the diagnosis andprognosis of cardiovascular diseases.A stratified analysis, based on ethnicity and different disease types and detectionmethods, was performed to study the other influencing factors. A subgroup analysis basedon ethnicity further showed that there were significant correlations between thers1042713 and rs1042714 polymorphisms and the risk of MI and CAD. Our results are inagreement with other studies indicating that the rs1042713 and rs1042714 polymorphismsin the Our study has some limitations. First, a study performed in a Saudi Arabian populationwas included in the present meta-analysis, and the results of that study were inagreement with our overall results. However, Saudi Arabia is a multi-racial population,which may influence the validity of the overall results. Second, very fewepidemiological studies have explored how the ADRB2 gene is related to thesusceptibility to MI or CAD, and most of the evidence that we gathered was frompublished composite coronary artery disease endpoints, including stroke, MI or CAD. Thismethodology may have restricted the extracted data. Third, all included studies had acase-control design; however, there were at least two apparent limitations. The samplesize was relatively small, and the designed case-control studies always precludedcausality. Therefore, it was difficult to reach a definitive conclusion. Fourth, withrespect to the stratified analysis, there was a limitation in the subgroup analyses, and there was significant heterogeneity insome subgroups, restricting the overall interpretation of the pooled risk estimation.Finally, we only analyzed two ADRB2 variants, excluding the potential influence of othervariants within the pathway.Despite the aforementioned limitations, our findings support that the rs1042713 andrs1042714 polymorphisms of the ADRB2 gene have a strong correlation with, MI and CAD,when tested under both the allele and dominant models, particularly among Asians. Thismeta-analysis might serve as an anchoring point for designing further studies anddeveloping ADRB2-based strategies to assess MI and CAD susceptibility.