Association between MTHFR polymorphisms and congenital heart disease: a meta-analysis based on 9,329 cases and 15,076 controls

Congenital septal defects in Karachi, Pakistan: an update of mutational screening by high-resolution melting (HRM) analysis of MTHFR C677T

BACKGROUND

Congenital heart defects (CHDs) are the heart structural malformations present at birth. Septal defects account for 40% of CHD, including atrial, ventricular and atrioventricular septal defects. In Pakistan, the prevalence of CHD is 3.4 in 1000, and a study estimated that 60,000 babies are born with CHD annually. Methylenetetrahydrofolate reductase (MTHFR), a chief enzyme, involved in the folate metabolism. The missense mutation, C677T (rs1801133), exists in MTHFR gene, results in a MTHFR thermolabile variant having low enzymatic activity. The study is aim to identify the MTHFR C677T variant association with septal defects.

METHODS

Samples of 194 CHD patients (age [Formula: see text]= 5.8 ± 5.1) and 50 normal echo controls (age [Formula: see text]= 6.0 ± 4.9), confirmed by pediatric consultant, were collected. Extracted DNA, quantified by agarose gel electrophoresis and nanodrop, was screened for SNP by high-resolution melting (HRM). Further, HRM results were confirmed using restriction analysis and sequencing. HRM was simply and precisely genotyped the samples within 3 h at low cost.

RESULTS

Genotypic data suggested that heterozygous mutant (CT) was frequent in congenital septal defect patients (0.26) which was higher than controls (0.143), p > 0.05. Mutant (TT) genotype was not found in this study.

CONCLUSIONS

rs1801133 has lack of significant association with congenital septal defects. The absence of TT genotype in this study suggesting the role of natural selection in targeted population. HRM is an easy, fast and next generation of PCR, which may be used for applied genomics.

ALDH2 rs671 and MTHFR rs1801133 polymorphisms are risk factors for arteriosclerosis in multiple arteries

BACKGROUND

Arteriosclerosis in multiple arteries has long been associated with heightened cardiovascular risk. Acetaldehyde dehydrogenase 2 (ALDH2) and methylenetetrahydrofolate reductase (MTHFR) play an important role in the pathogenesis of arteriosclerosis by participating in the oxidation and reduction reactions in vascular endothelial cells. The purpose was to investigate the relationship of ALDH2 and MTHFR gene polymorphisms with arteriosclerosis in multiple arteries.

METHODS

410 patients with arteriosclerosis in single artery and 472 patients with arteriosclerosis in multiple arteries were included. The relationship between ALDH2 rs671 and MTHFR rs1801133 polymorphisms and arteriosclerosis in single artery and arteriosclerosis in multiple arteries was analyzed.

RESULTS

The proportion of ALDH2 rs671 A allele (35.6% vs. 30.9%, P = 0.038) and MTHFR rs1801133 T allele (32.6% vs. 27.1%, P = 0.012) in patients with arteriosclerosis in multiple arteries was significantly higher than that in arteriosclerosis in single artery, respectively. The proportion of history of alcohol consumption in patients with ALDH2 rs671 G/G genotype was higher than those in ALDH2 rs671 G/A genotype and A/A genotype (P < 0.001). The results of logistic regression analysis indicated that ALDH2 rs671 A/A genotype (A/A vs. G/G: OR 1.996, 95% CI: 1.258-3.166, P = 0.003) and MTHFR rs1801133 T/T genotype (T/T vs. C/C: OR 1.943, 95% CI: 1.179-3.203, P = 0.009) may be independent risk factors for arteriosclerosis in multiple arteries (adjusted for age, sex, smoking, drinking, hypertension, and diabetes).

CONCLUSIONS

ALDH2 rs671 A/A and MTHFR rs1801133 T/T genotypes may be independent risk factors for arteriosclerosis in multiple arteries.

Association between MTHFR C677T variant and risk for congenital heart defects in Egyptian children: a case–control study including meta-analysis based on 147 cases and 143 controls

Background

Stratification analysis studies showed that ethnicity has a significant association regarding MTHFR C677T variant and congenital heart diseases (CHDs) risk, and many published studies have controversial conclusions toward this association.

Methods

In this study, the association between the MTHFR C677T variant and the risk for CHDs was evaluated in 91 children with CHD and 95 healthy controls, as new cases, by using restriction fragment length polymorphism (RFLP) technique. Besides that, 2 case–control studies in the Egyptian population published before 2021 were included in this meta-analysis. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI) based on 294 alleles in CHD cases and 286 alleles in controls.

Results

The overall meta-analysis showed a significant association between MTHFR C677T variant and CHDs risk in Egyptian children with heterogeneity (Heterogeneity = 0.001) in all the genetic models with the highly significant association in T versus C allele (pooled OR 1.89, 95% CI 1.31–2.74; p value < 0.0004). The consistency of the genotypes was detected by Hardy–Weinberg equilibrium (HWE).

Conclusions

Our results support the MTHFR -677T allele as a susceptibility factor for CHDs in the Egyptian pediatric patients.

Reduced Steroid Synthesis in the Follicular Fluid of MTHFR 677TT Mutation Carriers: Effects of Increased Folic Acid Administration

Objective To compare steroid profiles in the follicular fluid (FF) from women homozygous for the methylenetetrahydrofolate reductase (MTHFR) 677C>T mutation and wildtype controls and to correlate it with the folic acid administration scheme applied at the time of oocyte retrieval. Design Retrospective single center study. Subjects and Methods Infertile patients treated by using assisted reproductive techniques were genotyped routinely for the MTHFR 677C>T mutation. In 2006 they had received folic acid supplementation doses of 400 µg daily per os. This group was designated Group-400 (n = 10). From 2008 onwards, all of our infertility patients received a daily dose of 800 µg folic acid per os. Women from this group were designated Group-800 (n = 28). FF were collected and a panel of steroid hormones (estradiol, estrone, estriol, cortisol, progesterone, 17-OH progesterone, testosterone, androstenedione, aldosterone, DHEA, and DHEA-S) was measured by isotope dilution liquid chromatography-tandem mass spectrometry employing atmospheric pressure photo ionization (APPI). Results In Group-400, the FF hormone profile confirmed a significant reduction of estradiol in homozygous 677TT carriers (0.52 ± 0.08-fold, exact p = 0.032) and for the first time also revealed significantly reduced estriol concentrations in these individuals (0.54 ± 0.05-fold, p = 0.016), as compared to wildtype controls. In Group-800, no significant differences were found for concentrations of any of the steroid hormones between homozygous 677TT carriers and wildtype controls. Conclusions The current findings support and extend previous reports on reduced concentrations of specific steroid hormones in follicular fluids of homozygous MTHFR 677C>T mutation carriers. The restoration of the FF hormone profile by elevated-dose folic acid supplementation might impact performing ART in infertile women with the MTHFR 677TT-genotype. Further adequately powered studies are necessary to verify our finding and to demonstrate the clinical effect of enhanced folic supplementation on ovarian function.

APOE Genetic Polymorphism rs7412 T/T Genotype May Be a Risk Factor for Essential Hypertension among Hakka People in Southern China

Objective

One of the causes of hypertension is a genetic factor. The purpose of this study was to look at the relationship between apolipoprotein E (APOE) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms and essential hypertension in the Hakka population.

Methods

The study included 2,850 patients with hypertension and 2,034 controls. APOE rs429358, rs7412, and MTHFR rs1801133 were genotyped by polymerase chain reaction (PCR)-microarray. The differences in these polymorphisms between the two groups were analyzed.

Results

The genotype and allele frequency of APOE and MTHFR polymorphisms did not differ significantly between hypertensive patients and controls. Patients with hypertension who were APOE rs429358C/C homozygous had higher TG, TC, LDL-C, and Apo-B levels, whereas patients with the T/T genotype had higher HDL-C levels. Patients with hypertension who were APOE rs7412T/T homozygous had higher TG and TC levels and lower LDL-C and Apo-B levels. Homocysteine (Hcy) levels in patients with MTHFR CC, CT, and TT genotypes were increased, while patients with the TT genotype and T allele had higher Hcy levels than those of patients with other genotypes and the C allele. The APOE rs7412T/T genotype in the co-dominant model (APOE rs7412T/T vs. C/C) (gender-, age-, smoking-, and drinking-adjusted OR 2.682, 95% CI, 1.072–6.710, P=0.035) was a significant risk factor for hypertension. The APOE rs429358 and MTHFR rs1801133 genotypes in co-dominant, dominant, and recessive models were not significant risk factors for hypertension.

Conclusions

It supports that APOE polymorphisms are related to hypertension in the Hakka population. Specifically, the APOE rs7412T/T genotype may be a risk factor for hypertension.

Super-assembly of integrated gold magnetic assay with loop-mediated isothermal amplification for point-of-care testing

With the increasing global threat of various diseases and infections, it is essential to develop a fast, low-cost, and easy-to-use point-of-care testing (POCT) system for inspections at all levels of medical institutions and self-examination at home. In this work, gold magnetic nanoparticles (GMNPs) are used as the key material, and a rapid visual detection method is designed through integrating loop-mediated isothermal amplification (LAMP) and lateral flow assay (LFA) biosensor for detecting a variety of analytes which includes whole blood, buccal swabs, and DNA. It is worth to note that the proposed method does not need DNA extraction. Furthermore, uracil DNA glycosylase (UDG) is employed to eliminate carrier contamination for preventing false positive results. The whole detection process can be finished within 25 min. The accuracy of detection is measured by assessing the polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) C677T. The detection limit of the newly developed extraction-free detection system for MTHFR C677T is 0.16 ng/μL. A preliminary clinical study of the proposed method is carried out by analyzing 600 clinical samples (including 200 whole blood samples, 100 buccal swabs, and 300 genomic DNA samples). The results indicate that the proposed method is 100% consistent with the sequencing results which provides a new choice for POCT and shows a broad application prospect in all levels of medical clinics and at home.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (details for MTHFR C677T primer sequences, the cell count results of samples at different dilution ratios, genotyping results and frequency samples, a Hardy-Weinberg equilibrium test, the sensitivity of the system, detection results of multiple samples, and optimization of the system) is available in the online version of this article at 10.1007/s12274-022-4692-9.

A Common Polymorphism in the MTHFD1 Gene Is a Modulator of Risk of Congenital Heart Disease

Several environmental and genetic factors may influence the risk of congenital heart defects (CHDs), which can have a substantial impact on pediatric morbidity and mortality. We investigated the association of polymorphisms in the genes of the folate and methionine pathways with CHDs using different strategies: a case–control, mother–child pair design, and a family-based association study. The polymorphism rs2236225 in the MTHFD1 was confirmed as an important modulator of CHD risk in both, whereas polymorphisms in MTRR, FPGS, and SLC19A1 were identified as risk factors in only one of the models. A strong synergistic effect on the development of CHDs was detected for MTHFD1 polymorphism and a lack of maternal folate supplementation during early pregnancy. A common polymorphism in the MTHFD1 is a genetic risk factor for the development of CHD, especially in the absence of folate supplementation in early pregnancy.

MTHFD1 c.1958G>A and TCN2 c.776G>C polymorphisms of folate metabolism genes and their implication for oral cavity cancer

Background

Cancers of the head and neck can damage the brain, spinal cord, and nerves, as well as the sense organs responsible for contact with the outside world. Oncogenic transformation occurs following mutations that change the function of specific genes, such tumor suppressor genes or oncogenes, and their encoded protein products. Therefore, the aim of this study was to evaluate the relationship between the occurrence of MTHFD1 c.1958G>A and TCN2 c.776G>C gene polymorphisms and the risk of oral cavity cancer.

Materials and methods

The study population consisted of 439 patients and 200 healthy subjects. Genomic DNA was extracted from peripheral blood and from paraffin-embedded tissue. Analysis of the gene polymorphisms was performed using polymerase chain reaction–restriction fragment length polymorphism.

Results

Statistically significant differences were found in the distribution of genotypes of the rs2236225 and rs1801198 polymorphisms between patients and controls. Regarding MTHFD1 c.1958G>A, the GA genotype (p<0.0001, OR = 2.91, 95% CI = 1.88–4.49-GA) was more common among patients than healthy subjects. Regarding TCN2 c.776G>C, the frequency of CC genotype (p< 0.0001, OR = 0.17, 95% CI = 0.10–0.33-CC) was significantly less common among patients than healthy subjects. Tobacco smoking, alcohol use, and male gender (p<0.0001) were found to be predictors of the disease.

Conclusion

The results suggest that the MTHFD1 c.1958G>A polymorphism may be associated with a greater risk of oral cavity cancer, whereas a protective effect has been found for the TCN2 c.776G>C polymorphism.

Association of ALDH2 rs671 and MTHFR rs1801133 polymorphisms with hypertension among Hakka people in Southern China

Background

Genetic factors play an important role in susceptibility to hypertension. Herein, the association between acetaldehyde dehydrogenase 2 (ALDH2) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and hypertension was analyzed among Hakka population in southern China.

Methods

A total of 3057 hypertensive patients and 2215 controls were enrolled. The ALDH2 rs671 and MTHFR rs1801133 genotyping were analyzed using gene chip. Relevant information and medical records of these subjects were collected.

Results

Hypertensive patients with ALDH2 rs671 G/A heterozygous had lower systolic blood pressure (SBP) than other genotypes (P < 0.001), while hypertensive patients with A allele had lower diastolic blood pressure (DBP) than patients with G allele (P < 0.001). The level of plasma homocysteine (Hcy) in patients with MTHFR CC, CT and TT genotypes showed an increasing trend (P < 0.001). The ALDH2 G/A genotype in the co-dominant model (adjusted OR 1.251, 95% CI 1.024–1.528, P = 0.028) and ALDH2 A/A genotype in the recessive model (adjusted OR 1.221, 95% CI 1.008–1.478, P = 0.041) were significant risk factors for the presence of hypertension. The MTHFR C/T genotype in the co-dominant model (adjusted OR 1.307, 95% CI 1.039–1.643, P = 0.022) and MTHFR C/T and T/T genotypes in the dominant model (adjusted OR 1.281, 95% CI 1.146–1.430, P < 0.001) were significant risk factors for the presence of hypertension. Further, logistic regression analysis showed that age, smoking, alcohol consumption, hyperhomocysteinemia, and high level of serum TG, Apo-A1, Apo-B were significant risks for hypertension.

Conclusions

In summary, ALDH2 rs671 G/A, A/A genotypes and MTHFR rs1801133 C/T, T/T genotypes may be risk factors for hypertension in this Chinese Hakka population.

Maternal Risk Factors Triggering Congenital Heart Defects in Down Syndrome: A Case-Control Study

OBJECTIVES

Maternal MTHFR and MTRR polymorphisms as a risk of CHD in DS fetus were studied along with maternal folic acid supplementation, which could influence the folate metabolism along with other risk factors.

MATERIAL AND METHODS

A case-control study comprising of mothers of DS with and without CHD along with controls were recruited from a tertiary care center since 2018-2019. Genomic DNA was isolated followed by PCR-RFLP.

RESULTS

Mothers with age ≥35 years and having history of miscarriages have a higher risk of giving birth to DS with CHD (n = 35% and 42%, respectively). Mothers who carried the MTHFR 677CT/TT and MTRR 524CT/TT genotypes combination in the folic acid nonusers group during pregnancies had six-fold (OR = 6.909, p-value = 0.027; 95% CI-1.23 ± 38.51) and four-fold (OR = 4.75, p-value = 0.040; 95% CI-1.067 ± 21.44) increased odds of having a DS child with CHD, respectively, as compared to folic acid users.

CONCLUSION

Maternal age, folic acid supplementation, and previous history of miscarriages is involved in the etiology of CHD in DS fetus in Indian population. Maternal MTHFR and MTRR polymorphisms are also involved in the occurrence of CHD and DS in Indian population when controlling for periconceptional folic acid supplementation.

LIMITATIONS

Single-Centered Study.

Neuroplacentology in congenital heart disease: placental connections to neurodevelopmental outcomes

Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta-heart-brain connection. IMPACT: Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.

Environmental and Genetic Risk Factors of Congenital Anomalies: an Umbrella Review of Systematic Reviews and Meta-Analyses

BACKGROUND

The prevalence of congenital anomalies in newborns in South Korea was 272.9 per 100,000 in 2005, and 314.7 per 100,000 in 2006. In other studies, the prevalence of congenital anomalies in South Korea was equivalent to 286.9 per 10,000 livebirths in 2006, while it was estimated 446.3 per 10,000 births during the period from 2008 to 2014. Several systematic reviews and meta-analyses analyzing the factors contributing to congenital anomalies have been reported, but comprehensive umbrella reviews are lacking.

METHODS

We searched PubMed, Google Scholar, Cochrane, and EMBASE databases up to July 1, 2019, for systematic reviews and meta-analyses that investigated the effects of environmental and genetic factors on any type of congenital anomalies. We categorized 8 subgroups of congenital anomalies classified according to the 10th revision of the International Statistical Classification of Diseases (ICD-10). Two researchers independently searched the literature, retrieved the data, and evaluated the quality of each study.

RESULTS

We reviewed 66 systematic reviews and meta-analyses that investigated the association between non-genetic or genetic risk factors and congenital anomalies. Overall, 269 associations and 128 associations were considered for environmental and genetic risk factors, respectively. Congenital anomalies based on congenital heart diseases, cleft lip and palate, and others were associated with environmental risk factors based on maternal exposure to environmental exposures (air pollution, toxic chemicals), parental smoking, maternal history (infectious diseases during pregnancy, pregestational and gestational diabetes mellitus, and gestational diabetes mellitus), maternal obesity, maternal drug intake, pregnancy through artificial reproductive technologies, and socioeconomic factors. The association of maternal alcohol or coffee consumption with congenital anomalies was not significant, and maternal folic acid supplementation had a preventive effect on congenital heart defects. Genes or genetic loci associated with congenital anomalies included MTHFR, MTRR and MTR, GATA4, NKX2-5, SRD5A2, CFTR, and 1p22 and 20q12 anomalies.

CONCLUSION

This study provides a wide perspective on the distribution of environmental and genetic risk factors of congenital anomalies, thus suggesting future studies and providing health policy implications.

Association analysis of maternal MTHFR gene polymorphisms and the occurrence of congenital heart disease in offspring

BACKGROUND

Although many studies showed that the risk of congenital heart disease (CHD) was closely related to genetic factors, the exact pathogenesis is still unknown. Our study aimed to comprehensively assess the association of single nucleotide polymorphisms (SNPs) of maternal MTHFR gene with risk of CHD and its three subtypes in offspring.

METHODS

A case-control study involving 569 mothers of CHD cases and 652 health controls was conducted. Thirteen SNPs were detected and analyzed.

RESULTS

Our study showed that genetic polymorphisms of maternal MTHFR gene at rs4846052 and rs1801131 were significantly associated with risk of CHD in the homozygote comparisons (TT vs. CC at rs4846052: OR = 7.62 [95%CI 2.95-19.65]; GG vs. TT at rs1801131: OR = 5.18 [95%CI 2.77-9.71]). And six haplotypes of G-C (involving rs4846048 and rs2274976), A-C (involving rs1801133 and rs4846052), G-T (involving rs1801133 and rs4846052), G-T-G (involving rs2066470, rs3737964 and rs535107), A-C-G (involving rs2066470, rs3737964 and rs535107) and G-C-G (involving rs2066470, rs3737964 and rs535107) were identified to be significantly associated with risk of CHD. Additionally, we observed that a two-locus model involving rs2066470 and rs1801131 as well as a three-locus model involving rs227497, rs1801133 and rs1801131 were significantly associated with risk of CHD in the gene-gene interaction analyses. For three subtypes including atrial septal defect, ventricular septal defect and patent ductus arteriosus, similar results were observed.

CONCLUSIONS

Our study indicated genetic polymorphisms of maternal MTHFR gene were significantly associated with risk of fetal CHD in the Chinese population. Additionally, there were significantly interactions among different SNPs on risk of CHD. However, how these SNPs affect the development of fetal heart remains unknown, and more studies in different ethnic populations and with a larger sample are required to confirm these findings.

Maternal Hypertension-Related Genotypes and Congenital Heart Defects

BACKGROUND

Maternal hypertension has been associated with congenital heart defect occurrence in several studies. We assessed whether maternal genotypes associated with this condition were also associated with congenital heart defect occurrence.

METHODS

We used data from the National Birth Defects Prevention Study to identify non-Hispanic white (NHW) and Hispanic women with (cases) and without (controls) a pregnancy in which a select simple, isolated heart defect was present between 1999 and 2011. We genotyped 29 hypertension-related single nucleotide polymorphisms (SNPs). We conducted logistic regression analyses separately by race/ethnicity to assess the relationship between the presence of any congenital heart defect and each SNP and an overall blood pressure genetic risk score (GRS). All analyses were then repeated to assess 4 separate congenital heart defect subtypes.

RESULTS

Four hypertension-related variants were associated with congenital heart defects among NHW women (N = 1,568 with affected pregnancies). For example, 1 intronic variant in ARHGAP2, rs633185, was associated with conotruncal defects (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1-1.6). Additionally, 2 variants were associated with congenital heart defects among Hispanic women (N = 489 with affected pregnancies). The GRS had a significant association with septal defects (OR: 2.1, 95% CI: 1.2-3.5) among NHW women.

CONCLUSIONS

We replicated a previously reported association between rs633185 and conotruncal defects. Although additional hypertension-related SNPs were also associated with congenital heart defects, more work is needed to better understand the relationship between genetic risk for maternal hypertension and congenital heart defects occurrence.

Association between interleukin-10 gene polymorphisms and risk of oral carcinoma: A meta-analysis

BACKGROUND

The single nucleotide polymorphisms (SNPs) of Interleukin-10 (IL-10) gene have been linked with the risk of oral carcinoma (OC) in a relatively small sample size. Our study aims to investigate the pooled associations by conducting a meta-analysis of published studies.

METHODS

PubMed, Web of Science and Google Scholar databases were searched to identify eligible studies published in English before October 2019. The odds ratio (OR) with a 95% confidence interval (CI) was used to assess association. The publication bias was detected by Begg's test. Sensitivity and cumulative analyses were performed to evaluate the stability of crude results.

RESULTS

The meta-analysis involved eight studies. Significant associations were certified between IL-10 gene -1082A/G polymorphism and susceptibility of OC for A vs. G (OR=1.817, 95% CI: 1.481-2.230), AA vs. GG (OR=3.436, 95% CI: 2.281-5.175), dominant genetic model (OR=2.913, 95% CI: 1.939-4.376), and recessive genetic model (OR=1.886, 95% CI: 1.372-2.594) in overall population, East Asians and South Asians. In addition, the significant association between -592A/C polymorphism of the gene and susceptibility of OC were detected in South Asians.

CONCLUSIONS

The meta-analysis results support that the IL-10 gene -1082G allele is a risk factor for OC in East Asians and South Asians, and IL-10 gene -592C allele is a protective factor for the disease.

Genetic Variants at the rs4720169 Locus of TBX20 and the rs12921862 Locus of AXIN1 May Increase the Risk of Congenital Heart Defects in the Mexican Population: A Pilot Study

Background: Congenital heart defects (CHDs) are the most common type of birth defects and a major cause of infant mortality. Although knowledge of genetic risk variants for CHDs is scarce, most cases of CHDs are considered to be due to multifactorial inheritance. Objective: To analyze the association of 14 single nucleotide polymorphic variants previously associated with a risk of CHDs in a Mexican population with isolated CHDs. Materials and Methods: DNA samples obtained from healthy subjects and from subjects with isolated atrial, ventricular, or atrioventricular septal defects living in Northeastern Mexico were analyzed by real time-polymerase chain reaction for allelic discrimination of genetic variants of the genes TBX1, TBX20, ASTX-18-AS1, AXIN1, MTHFR, NKX2.5, BMP4, and NFATc1. The odds ratios (ORs) for allele and genotype frequencies and inheritance models were obtained. Results: Forty-two patients and 138 controls were included. Two variants were found to confer a risk of CHDs: variant rs4720169 of TBX20 in which the OR for the heterozygous state was 1.88 (95% confidence interval [CI]: 1.12-3.14, p = 0.010), whereas the OR for the homozygous state was 3.82 (95% CI: 1.18-12.3, p = 0.010); and variant rs12921862 of AXIN1 in which the OR for the heterozygous state was 4.15 (95% CI: 2.42-7.10; p ≤ 0.001), whereas the OR for the homozygous state was 9.2 (95% CI: 1.31-64.7, p = 0.008) for allele A. Conclusion: Genetic variants of the TBX20 and AXIN1 genes confer a significantly increased risk of congenital septal heart defects in a population from Northeastern Mexico.

The association of elevated maternal genetic risk scores for hypertension, type 2 diabetes and obesity and having a child with a congenital heart defect

Background

Maternal hypertension, type 2 diabetes (T2D) and obesity are associated with an increased risk of having offspring with conotruncal heart defects (CTDs). Prior studies have identified sets of single nucleotide polymorphisms (SNPs) that are associated with risk for each of these three adult phenotypes. We hypothesized that these same SNPs are associated with maternal risk of CTDs in offspring.

Methods and results

We evaluated the parents of children with a CTD ascertained from the Children’s Hospital of Philadelphia (n = 466) and by the Pediatric Cardiac Genomic Consortium (n = 255). We used a family-based design to assess the association between CTDs and the maternal genotype for individual hypertension, T2D, and obesity-related SNPs and found no association between CTDs and the maternal genotype for any individual SNP. In addition, we calculated genetic risk scores (GRS) for hypertension, T2D, and obesity using previously published GRS formulas. When comparing the GRS of mothers to fathers, there were no statistically significant differences in the mean for the combined GRS or the GRS for each individual condition. However, when we categorized the mothers and fathers of cases with CTDs as having high (>95^th percentile) or low (≤95^th percentile) scores, compared to fathers, mothers had almost two times the odds of having a high GRS for hypertension (OR 1.7, 95% CI 1.0, 2.8) and T2D (OR 1.8, 95% CI 1.1, 3.1).

Conclusions

Our results support a link between maternal genetic risk for hypertension/T2D and CTDs in their offspring. These associations might be independent of maternal phenotype at conception.

Maternal LINE-1 DNA Methylation and Congenital Heart Defects in Down Syndrome

Background: Down syndrome (DS) is one of the most common chromosomal abnormalities associated with congenital heart defects (CHD), with approximately 40 to 60% of cases showing cardiac defects. This study assessed (i) the association between maternal LINE-1 methylation and the occurrence of CHDs in children with DS and (ii) the impact of endogenous maternal factors (MTHFR C677T polymorphism and maternal age) and exogenous maternal factors (cigarette smoking, alcohol intake, medication use, body mass index and dietary habits such as folate intake) on maternal LINE-1 methylation and on the occurrence of CHD in children with DS.

Patients and Methods: The study included 90 mothers of children with DS of maternal origin (49% DS-CHD⁺ mothers/51% DS-CHD⁻ mothers). LINE-1 DNA methylation was analyzed in peripheral blood lymphocytes by quantification of LINE-1 methylation using the MethyLight method. MTHFR C677T polymorphism genotyping was performed using PCR-RFLP.

Results: LINE-1 methylation was not significantly different between DS-CHD⁺ and DS-CHD⁻ mothers (P = 0.997). Combination of MTHFR C677T genotype/diet and BMI were significant independent predictors of LINE-1 DNA methylation in DS-CHD⁺ mothers (β −0.40, P = 0.01 and β −0.32, P = 0.03, respectively). In the analyzed multivariate model (model P = 0.028), these two factors explained around 72% of the variance in LINE-1 DNA methylation in mothers of children with DS and CHD. The group with the highest BMI (≥30 kg/m2) had significantly lower LINE-1 methylation than the group with normal BMI (Bonferroni post hoc P = 0.03) and the overweight group (Bonferroni post hoc P = 0.04). The lowest LINE-1 DNA methylation values were found in DS-CHD⁺ mothers with the CT+TT genotype and a low-folate diet; the values were significantly lower than the values in mothers with the CC genotype and a folate-rich diet (Bonferroni post hoc P = 0.04).

Conclusion: Association between maternal LINE-1 methylation and CHD in children with DS was not found. Study showed that the MTHFR genotype/diet combination and BMI were significantly associated with LINE-1 methylation in mothers of children with DS-CHD⁺. These results highlight the need for a multifactorial approach to assess the roles of endogenous and exogenous maternal factors in maternal LINE-1 DNA methylation and the consequent pathologies in children. More extensive studies in a larger sample may help elucidate these relationships.

Meta-Prediction of MTHFR Gene Polymorphism and Air Pollution on the Risks of Congenital Heart Defects Worldwide: A Transgenerational Analysis

Congenital heart disease (CHD) is the leading cause of death in children, and is affected by genetic and environmental factors. To investigate the association of air pollution with methylene-tetrahydrofolate reductase (MTHFR) polymorphisms and the risk of CHD, we included 58 study groups of children and parents, with 12,347 cases and 18,106 controls worldwide. Both MTHFR C677T (rs 1801133) and A1298C (rs 1801131) gene polymorphisms were risks for CHD in children with transgenerational effects from their parents. Countries with greater risks of CHD with a pooled risk ratio (RR) > 2 from MTHFR 677 polymorphisms included Germany, Portugal, China, and Egypt for children; and Brazil, Puerto Rico, Mexico, China, and Egypt for mothers. Whereas, countries with greater risk of CHD with RR > 2 from MTHFR 1298 polymorphisms included Taiwan, Turkey, and Egypt for children; and Brazil, China, and Egypt for mothers. Additionally, meta-prediction analysis revealed that the percentages of MTHFR 677TT and TT plus CT polymorphisms together were increased in countries with higher levels of air pollution, with a trend of increased CHD risks with higher levels of air pollution for children (p = 0.07). Our findings may have significant implications for inflammatory pathways in association with MTHFR polymorphisms and future intervention studies to correct for folate-related enzyme deficits resulted from MTHFR polymorphisms to prevent CHDs for future generations.

A Targeted, Next-Generation Genetic Sequencing Study on Tetralogy of Fallot, Combined With Cleft Lip and Palate

Background:

Congenital heart disease (CHD), plus cleft lip and palate (CLP) are currently the most common types of structural malformation in infants. Many genes have been investigated for their involvement in CHD with CLP. Targeted next-generation sequencing can analyze large amounts of genetic information rapidly, and thus address this question.

Methods:

The authors designed a targeted, next-generation sequencing gene panel for 455 genes previously implicated in CHD or CLP. A single-subject patient served as a genetic source. Variants that affect protein-coding regions were classified into silico and filtered through databases, such as the Single-Nucleotide Polymorphism Database, Yan Huang, the Exome Sequencing Project, and the 1000 Genomes Project. The authors then predicted the function of gene mutations by PolyPhen-2, SIFT, and Mutation Taster. To confirm the related disease genes, the authors surveyed relevant literature on PubMed. Finally, the variant was verified by Sanger sequencing.

Results:

A total of 1520 mutations were successfully found in a patient using combined tetralogy of Fallot and CLP by the targeted next-generation sequencing. However, there were 6 gene mutations (ZNF528, PVRL2, methylenetetrahydrofolate reductase [MTHFR], EVC2, DAND5, CCDC39) that were not found on Single-Nucleotide Polymorphism Database, Yan Huang, Exome Sequencing Project, and 1000 Genomes Project. Four genes (ZNF528, PVRL2, EVC2, CCDC39) were all predicted to be “tolerated,” “benign,” or “polymorphic” by SIFT, PolyPhen-2, and Mutation Taster. The DAND5 gene was predicted to be “possibly damaging” and “disease causing” respectively by PolyPhen-2 and Mutation Taster, but the SIFT program predicted this mutation to be “tolerated.” Likewise, the MTHFR gene mutation was predicted to be “damaging,” “possibly damaging,” and “disease causing” respectively by SIFT, PolyPhen-2, and Mutation Taster. There is no relevant report about MTHFR gene mutation (c.G586A, p.G196S) on PubMed.

Conclusion:

Using targeted, next-generation sequencing technology, the authors identified for the first time a mutation (c.G586A, p.G196S) in the MTHFR gene as a possible cause of TOF and CLP in a patient.

Systematic review and meta-analysis of the associations between maternal methylenetetrahydrofolate reductase polymorphisms and preterm delivery

AIM

To date, reported associations between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and preterm delivery are conflicting. The present meta-analysis summarized the existing evidence and evaluated these associations.

METHODS

Eligible studies were retrieved from Medline (PubMed), EMBASE, the Chinese Biomedical Literature Database and the Cochrane Library. We calculated pooled odds ratios (ORs) and 95% confidence interval (CIs) within five genetic models using either random-effects or fixed-effects models dependent on study heterogeneity. Potential publication bias was assessed using a Begg's test. Sensitivity analysis was performed to evaluate the stability of the results.

RESULTS

Thirteen studies involving 4816 mothers who experienced preterm delivery and 34 506 normal controls were finally included. Significant associations between MTHFR C677T polymorphism and the risk of preterm delivery were detected overall (OR_T/C  = 1.34, 95% CI 1.12-1.61; OR_TT/CC  = 1.60, 95% CI 1.21-2.11; OR_CT/CC  = 1.33, 95% CI 1.07-1.65; OR_{TT/(CC + CT)}  = 1.41, 95% CI 1.11-1.78; OR_{(TT + CT)/CC}  = 1.36, 95% CI 1.11-1.66) and in an Asian population (OR_T/C  = 1.80, 95% CI 1.24-2.62; OR_TT/CC  = 2.13, 95% CI 1.27-3.57; OR_CT/CC  = 1.93, 95% CI 1.37-2.71; OR_{(TT + CT)/CC}  = 2.03, 95% CI 1.49-2.77). Negative associations of the A1298C polymorphism were only observed among Asian pregnant women (OR_C/A  = 0.66, 95% CI 0.50-0.88; OR_CC/AA  = 0.10, 95% CI 0.02-0.53; OR_{CC/(AA + AC)}  = 0.11, 95% CI 0.02-0.57; OR_{(CC + AC)/AA}  = 0.68, 95% CI 0.49-0.94).

CONCLUSIONS

MTHFR 677 T may play a significant role in regard to the risk of preterm delivery, especially in the Asian population.

MTHFR A1298C polymorphisms reduce the risk of congenital heart defects: a meta-analysis from 16 case-control studies

Background

Methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in the hyperhomocysteinemia, which is a risk factor related to the occurrence of congenital heart defect (CHD). However, the association between MTHFR polymorphism and CHD has been inconclusive.

Methods

We conducted an updated meta-analysis to provide comprehensive evidence on the role of MTHFR A1298C polymorphism in CHD. Databases were searched and a total of 16 studies containing 2207 cases and 2364 controls were included.

Results

We detected that a significant association was found in the recessive model (CC vs. AA + AC: OR = 1.38, 95% CI: 1.10–1.73) for the overall population. Subgroup analysis showed that associations were found in patients without Down Syndrome in genetic models for CC vs. AA (OR = 1.47, 95% CI: 1.01–2.14), CC vs. AC (OR = 1.29, 95% CI: 1.00–1.66) and recessive model (OR = 1.44, 95% CI: 1.14–1.82). We conducted a meta-regression analysis, Galbraith plots and a sensitivity analysis to assess the sources of heterogeneity.

Conclusions

In summary, our present meta-analysis supports the MTHFR 1298C allele as a risk factor for CHD. However, further studies should be conducted to investigate the correlation of plasma homocysteine levels, enzyme activity, and periconceptional folic acid supplementation with the risk of CHD.

Electronic supplementary material

The online version of this article (10.1186/s13052-017-0425-1) contains supplementary material, which is available to authorized users.

Lower Circulating Folate Induced by a Fidgetin Intronic Variant Is Associated With Reduced Congenital Heart Disease Susceptibility

BACKGROUND

Folate deficiency is an independent risk factor for congenital heart disease (CHD); however, the maternal plasma folate level is paradoxically not a good diagnostic marker. Genome-wide surveys have identified variants of nonfolate metabolic genes associated with the plasma folate level, suggesting that these genetic polymorphisms are potential risk factors for CHD.

METHODS

To examine the effects of folate concentration-related variations on CHD risk in the Han Chinese population, we performed 3 independent case-control studies including a total of 1489 patients with CHD and 1745 control subjects. The expression of the Fidgetin (FIGN) was detected in human cardiovascular and decidua tissue specimens with quantitative real-time polymerase chain reaction and Western blotting. The molecular mechanisms were investigated by luciferase reporter assays, surface plasmon resonance, and chromatin immunoprecipitation. FIGN-interacting proteins were confirmed by tandem affinity purification and coimmunoprecipitation. Proteasome activity and metabolite concentrations in the folate pathway were quantified with a commercial proteasome activity assay and immunoassays, respectively.

RESULTS

The +94762G>C (rs2119289) variant in intron 4 of the FIGN gene was associated with significant reduction in CHD susceptibility (P=5.1×10^-14 for the allele, P=8.5×10^--13 for the genotype). Analysis of combined samples indicated that CHD risks in individuals carrying heterozygous (GC) or homozygous (CC) genotypes were reduced by 44% (odds ratio [OR]=0.56; 95% confidence interval [CI]=0.47-0.67) and 66% (OR=0.34; 95% CI=0.23-0.50), respectively, compared with those with the major GG genotype. Minor C allele carriers who had decreased plasma folate levels exhibited significantly increased FIGN expression because the transcription suppressor CREB1 did not bind the alternative promoter of FIGN isoform X3. Mechanistically, increased FIGN expression led to the accumulation of both reduced folate carrier 1 and dihydrofolate reductase via inhibition of their proteasomal degradation, which promoted folate absorption and metabolism.

CONCLUSIONS

We report a previously undocumented finding that decreased circulating folate levels induced by increased folate transmembrane transport and utilization, as determined by the FIGN intronic variant, serves as a protective mechanism against CHD. Our results may explain why circulating folate levels do not have a good diagnostic value.

Influence of MTHFR C677T gene polymorphism in the development of cardiovascular disease in Egyptian patients with rheumatoid arthritis

OBJECTIVE

To investigate the association between increased carotid intima-media thickness (CIMT), homocysteine level, and MTHFR C677T (rs1801133) gene polymorphism in Egyptian people with rheumatoid arthritis (RA).

SUBJECTS AND METHODS

280 Egyptian women (160 RA patients and 120 controls) were included in the study. CIMT was measured using high resolution B-mode ultrasonography and homocysteine levels were measured using enzyme-linked immunosorbent assay. While, MTHFR C677T polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

We found that subjects who carried the TT genotype and T allele were significantly more likely to develop RA with 2.9 and 1.5 fold, respectively. RA patients carrying the T allele presented a statistically significant increased risk of developing atherosclerosis compared with those carrying the C allele. Moreover, MTHFR TT genotype was independent risk factor of thick CIMT.

CONCLUSIONS

C677T MTHFR gene polymorphism is associated with RA in Egyptians. MTHFR 677TT carriers had higher concentrations of serum Hcy than did subjects harboring the CC and CT genotypes. The presence of 677T allele increases the risk of atherosclerosis in patients with RA. This increased risk of atherosclerosis could be due to hyperhomocysteinemia.

Dimethylarginine Dimethylaminohydrolase 2 (DDAH 2) Gene Polymorphism, Asymmetric Dimethylarginine (ADMA) Concentrations, and Risk of Coronary Artery Disease: A Case-Control Study

Asymmetric dimethylarginine (ADMA) has been shown to be an independent predictor of cardiovascular diseases. Dimethylarginine dimethylaminohydrolase 2 (DDAH 2) promotes the metabolism of ADMA and plays a key role in the regulation of acute inflammatory response. With the present study, we investigated the relationship between DDAH 2 polymorphisms and risk of coronary artery disease (CAD) and its association to plasma ADMA concentrations. We used the haplotype-tagging SNP approach to identify tag SNPs in DDAH 2. The SNPs were genotyped by PCR and sequenced in 385 CAD patients and 353 healthy controls. Plasma concentrations of ADMA were determined using enzyme-linked immunosorbent assay (ELISA). A promoter polymorphism −449C/G (rs805305) in DDAH 2 was identified. Compared with the ADMA concentrations in CC genotype (0.328 ± 0.077 μmol/l), ADMA concentrations in CG + GG genotype were significantly increased (0.517 ± 0.090 μmol/l, P < 0.001). No significant associations between the −449C/G and risk of CAD were detected in the genetic models. The results of this study suggest that Genetic −499C/G polymorphism in DDAH 2 gene may affect the plasma ADMA concentrations in patients with CAD. However, it does not indicate a novel genetic risk marker for CAD.

Association of C677T MTHFR and G20210A FII prothrombin polymorphisms with susceptibility to myocardial infarction

Myocardial infarction (MI) is a common complex pathology, localized in the main leading causes of mortality worldwide. It is the result of the interaction of genetic and environmental factors. The aim of the present study was to investigate the potential association of C677T 5,10-methylenetetrahydrofolate reductase (MTHFR) (rs1801133) and G20210A factor II prothrombin (FII) (rs1799963) polymorphisms with the susceptibility of MI. Following extraction by the standard salting-out procedure, DNA samples of 100 MI patients and 182 apparently healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism using HinfI and HindIII restriction enzymes, respectively. The results show a significant association of the G20210T FII polymorphism with the MI risk. The frequencies of the heterozygote genotype GA, homozygous mutated AA and the G20210A allele was higher among patients compared to controls (GA: 59 vs. 5.5%, P<0.001; AA: 10 vs. 0%, P=0.003; and 20210A: 39.5 vs. 2.7%, P<0.003), suggesting that this polymorphism may be a potential genetic marker for MI. No significant association was observed between the C677T MTHFR and MI occurrence, and there was more heterozygote CT in the patient group compared to the controls. As a multifactorial disease, the development of MI may be the result of numerous factors that influence synergistically its occurrence. Thus, further studies are merited to try to better assess these associations (gene-gene and gene-environment interactions).

Evaluation of High Resolution Melting for MTHFR C677T Genotyping in Congenital Heart Disease

Background

High resolution melting (HRM) is a simple, flexible and low-cost mutation screening technique. The methylenetetrahydrofolate reductase (MTHFR) gene encoding a critical enzyme, potentially affects susceptibility to some congenital defects like congenital heart disease (CHD). We evaluate the performance of HRM for genotyping of the MTHFR gene C677T locus in CHD cases and healthy controls of Chinese Han population.

Methods

A total of 315 blood samples from 147 CHD patients (male72, female 75) and 168 healthy controls (male 92, female 76) were enrolled in the study. HRM was utilized to genotype MTHFR C677T locus of all the samples. The results were compared to that of PCR-RFLP and Sanger sequencing. The association of the MTHFR C677T genotypes and the risk of CHD was analyzed using odds ratio with their 95% confidence interval (CIs) from unconditional logistic regression.

Results

All the samples were successfully genotyped by HRM within 1 hour and 30 minutes while at least 6 hours were needed for PCR-RFLP and sequencing. The genotypes of MTHFR C677T CC, CT, and TT were 9.52%, 49.66%, and 40.82% in CHD group but 29.17%, 50% and 20.83% in control group, which were identical using both methods of HRM and PCR-RFLP, demonstrating the sensitivity and specificity of HRM were all 100%.

Conclusion

MTHFR C677T is a potential risk factor for CHD in our local residents of Shandong province in China. HRM is a fast, sensitive, specific and reliable method for clinical application of genotyping.

A novel lateral flow assay based on GoldMag nanoparticles and its clinical applications for genotyping of MTHFR C677T polymorphisms

Current techniques for single nucleotide polymorphism (SNP) detection require tedious experimental procedures and expensive and sophisticated instruments. In this study, a visual genotyping method has been successfully established via combining ARMS-PCR with gold magnetic nanoparticle (GoldMag)-based lateral flow assay (LFA) and applied to the genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T. C677T substitution of the gene MTHFR leads to an increased risk of diseases. The genotyping result is easily achievable by visual observation within 5 minutes after loading of the PCR products onto the LFA device. The system is able to accurately assess a broad detection range of initial starting genomic DNA amounts from 5 ng to 1200 ng per test sample. The limit of detection reaches 5 ng. Furthermore, our PCR-LFA system was applied to clinical trials for screening 1721 individuals for the C677T genotypes. The concordance rate of the genotyping results detected by PCR-LFA was up to 99.6% when compared with the sequencing results. Collectively, our PCR-LFA has been proven to be rapid, accurate, sensitive, and inexpensive. This new method is highly applicable for C677T SNP screening in laboratories and clinical practices. More promisingly, it could also be extended to the detection of SNPs of other genes.

The Ultrasonic Microsurgical Anatomical Comparative Study of the CHD Fetuses and Their Clinical Significance

The aim of our study was to increase the detection rate of fetal cardiac malformations for congenital heart disease (CHD). The ultrasonic and microanatomical methods were combined to study the CHD cases firstly, which could provide the microsurgical anatomical basis to the prenatal ultrasonic diagnosis which was used in suspected CHD and help the sonographer to improve the quality of fetal cardiac diagnosis. We established the ultrasonic standard section of the 175 complex CHD cases and collected the fetal echocardiography image files. The induced/aborted fetuses were fixed by 4% paraformaldehyde and dissected by the ultrasonic microsurgical anatomy. This research could obtain the fetal cardiac anatomic cross-sectional images which was consistent with the ultrasonic standard section and could clearly show the internal structure of the vascular malformation that optimized the ultrasound examination individually. This method could directly display the variation of the CHD fetal heart clearly and comprehensively help us to understand the complex fetal cardiac malformation from the internal structure of the vascular malformation which was consolidated by the anatomical basis of the fetal heart. This study could improve the integrity and accuracy of the prenatal cardiac ultrasound examination tremendously.

Genetic variations in MTHFR and gastric cardia adenocarcinoma susceptibility in the Chinese Han population

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms are associated with many types of cancers. The purpose of our study was to evaluate the effect of MTHFR single nucleotide polymorphisms (SNPs) on gastric cardia adenocarcinoma (GCA). We conducted a hospital-based case-control study. Three hundred and thirty cases with GCA and 608 controls were recruited. The ligation detection reaction (LDR) method was used to determine genotypes. The genotype MTHFR rs1801133 TT was significantly more frequent in cases than in controls (adjusted odds ratio (OR) = 1.46, 95% confidence interval (CI) = 1.04-2.05, P = 0.029) in a recessive model, after adjusting for age, sex and smoking and alcohol use. The haplotype MTHFR Grs4845882Ars4846048Trs1801133Crs9651118Ars3753584 was more frequent in cases than in controls (crude OR = 5.32, 95% CI = 2.34-12.10, P < 0.001). No association between other genotypes and haplotypes was observed. Our results suggest that the genotype MTHFR rs1801133 TT and the MTHFR Grs4845882Ars4846048Trs1801133Crs9651118Ars3753584 haplotype may be associated with susceptibility to GCA. Further studies are needed to confirm these findings.

Levels of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, and risk of coronary artery disease: A meta-analysis based on 4713 participants

BACKGROUND

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase by competing with L-arginine. As a result, the expression of nitric oxide decreases and endothelial dysfunction occurs. Studies have evaluated the association between the serum ADMA level and risk of coronary artery disease. However, conflicting results have been obtained.

METHODS

Pubmed, Web of Science, Embase, Ovid, Cochrane databases were searched to identify eligible studies published in English until December 2014. Association was assessed on the basis of weighted mean differences (WMD) with 95% confidence intervals (CIs). Publication bias was analysed using Begg's and Egger's tests. Sensitivity analysis was performed to evaluate result stability.

RESULTS

A total of 16 case-control studies with 2939 patients and 1774 controls were included in the meta-analysis. Pooled result indicated that patients with coronary artery disease yielded a higher ADMA level than healthy controls (WMD: 0.248, 95% CI: 0.156-0.340; p = 1.16 e-7). Sensitivity analysis suggested that our meta-analysis result was stable. Subgroup analysis found a similar pattern in patients with myocardial infarction (WMD: 0.397, 95% CI: 0.112-0.683; p = 0.0106), stable angina pectoris (WMD: 0.197, 95% CI: 0.031-0.364; p = 0.02) and unstable angina pectoris (WMD: 0.857, 95% CI: 0.293-1.420; p = 0.003).

CONCLUSIONS

Meta-analysis results indicated that an increased ADMA level is associated with an increased risk of coronary artery disease.

Evaluation of Gestational Diabetes Mellitus Risk in South Indian Women Based on MTHFR (C677T) and FVL (G1691A) Mutations

We aimed to scrutinize the extent to which single amino acid substitutions in the MTHFR and factor V Leiden (FVL) genes affect the risk of gestational diabetes mellitus (GDM) in pregnant women of South Indian descendant. This case-control study was implemented once the ethical approval has been obtained. Overall, 237 women were recruited in this study: 137 had been diagnosed with GDM and the remaining 100 women were used as normal controls or non-GDM. The diagnosis of GDM was confirmed with biochemical analysis, i.e., GCT and oral glucose tolerance tests. Five milliliters of peripheral blood was collected and used for biochemical and molecular analyses. DNA was isolated, and genotyping for MTHFR (C677T) and FVL (G1691A) mutations was performed using PCR-RFLP. FVL (G1691A) locus was not polymorphic in the investigated sample. There was no significant difference in the allele and genotype frequencies of C677T polymorphism between GDM and non-GDM women (p = 0.8892).