Association of MTHFR and RFC1 gene polymorphism with hyperhomocysteinemia and its modulation by vitamin B12 and folic acid in an Indian population

Global DNA Methylation Levels Viz-a-Viz Genetic and Biochemical Variations in One Carbon Metabolic Pathway: An Exploratory Study from North India

Despite the importance of one carbon metabolic pathway (OCMP) in modulating the DNA methylation process, only a few population-based studies have explored their relationship among healthy individuals. This study aimed to understand the variations in global DNA methylation levels with respect to selected genetic (CBS 844ins68, MTRR A66G, MTR A2756G, and MTHFR C677T polymorphisms) and biochemical (folate, vitamin B12, and homocysteine) markers associated with OCMP among healthy North Indian adults. The study has been conducted among 1095 individuals of either sex (69.5% females), aged 30-75 years. A sample of 5 mL of blood was collected from each participant. Homocysteine, folate, and vitamin B12 levels were determined using the chemiluminescence technique. Restriction digestion was performed for genotyping MTRR A66G, MTR A2756G, and MTHFR C677T polymorphisms and allele-specific PCR amplification for CBS 844ins68 polymorphism. Global DNA methylation levels were analyzed using ELISA-based colorimetric technique. Of the selected genetic and biochemical markers, the mutant MTRR A66G allele was positively associated with global DNA methylation levels. Further, advanced age was inversely associated with methylation levels. MTRR 66GG genotype group was hypermethylated than other genotypes in folate replete and vitamin B12 deficient group (a condition prevalent among vegetarians), suggesting that the G allele may be more efficient than the wild-type allele in such conditions. Global DNA methylation levels appeared to be more influenced by genetic than biochemical factors. MTRR 66G allele may have a selective advantage in vitamin B12 deficient conditions. Further research should be undertaken to understand how genetics affects epigenetic processes.

Combination of Taurine and Black Pepper Extract as a Treatment for Cardiovascular and Coronary Artery Diseases

The shift in modern dietary regimens to "Western style" and sedentary lifestyles are believed to be partly responsible for the increase in the global burden of cardiovascular diseases. Natural products have been used throughout human history as treatments for a plethora of pathological conditions. Taurine and, more recently, black pepper have gained attention for their beneficial health effects while remaining non-toxic even when ingested in excess. Taurine, black pepper, and the major terpene constituents found in black pepper (i.e., β-caryophyllene; α-pinene; β-pinene; α-humulene; limonene; and sabinene) that are present in PhytoCann BP^® have been shown to have cardioprotective effects based on anti-inflammatory, antioxidative, anti-hypertensive and anti-atherosclerotic mechanisms. This comprehensive review of the literature focuses on determining whether the combination of taurine and black pepper extract is an effective natural treatment for reducing cardiovascular diseases risk factors (i.e., hypertension and hyperhomocysteinemia) and for driving anti-inflammatory, antioxidative and anti-atherosclerotic mechanisms to combat coronary artery disease, heart failure, myocardial infarction, and atherosclerotic disease.

Hyperhomocysteinemia in men and women of married couples with reproductive disorders. What is the difference?

Hyperhomocysteinemia (HHcy) is an autosomal recessive inherited metabolic disease caused by variations in folate metabolism genes, characterized by impaired methionine metabolism and accumulation of homocysteine (Hcy) in the blood serum. It was shown that men usually have higher plasma Hcy levels than women, but have not yet assessed the leading factors of these differences, which is important for the development of personalized protocols for the prevention of folate metabolism disorders in couples with reproductive disorders. This study aimed to analyze the effect of intergenic and gene-factor interactions on the risk of developing HHcy in men and women of married couples with reproductive disorders. In our study were involved 206 married Caucasian couples (206 males and 206 females) from central regions of Ukraine with early pregnancy losses in the anamnesis. We found that the incidence of HHcy in men was significantly higher than in women. Gender differences in folic acid and vitamin B12 levels were identified. The best predictors of HHcy in men (MTRR (A66G), MTHFR (C677T), MTR (A2756G), vitamin B12 level) and in women (MTHFR (C677T), MTR (A2756G), vitamin B12 level) were selected by binary logistic regression. There was no significant difference in the distribution of genotypes by the studied gene variants when comparing men and women with HHcy. Our findings demonstrate that there is a gender difference in the development of HHcy. This difference is caused by intergenic interaction and by environmental factors, in particular, nutrition and vitamins consumption.

Homocysteine, Vitamin B12 and Folate Level: Possible Risk Factors in the Progression of Chronic Heart and Kidney Disorders

Cobalamin is an essential molecule for humans; it is exceptionally important for various body functions, including deoxyribonucleic acid synthesis and cellular energy production. Vegans are more vulnerable to vitamin B12 deficiency than natives with moderate consumption of animal dietary supplements or people with inadequate nutritional patterns. However, the long-term effects of sub-medical deficiency have not been thoroughly studied, but they may have a negative impact on the cardiovascular system, pregnancy outcomes, and vascular, renal, cognitive, bone, and eye health. Alongside the statin remedy, that is a powerful approach for CVD prevention. Another approach is related to the B nutrition substitution remedy with folic acid, and vitamins B6 and B12 are extensively practised nowadays. There is a tremendous interest in plasma homocysteine (tHcy) as a cardiovascular hazard factor. However, current research in the field of its prevention is more inclined toward confirming the benefit of tHcy-reducing remedy with vitamin B12. Thus, while folic acid fortification is primarily aimed at reducing neural-tube defects, it may also play a significant role in the primary prevention of CVD by lowering tHcy. Folate and B-vitamins play important roles in CVD prevention and nutrition policy implementation. Patients affected with Chronic Kidney Disease (CKD) or end-stage Stage Renal Disease (ESRD) experience a tremendous cardiovascular threat that may also further lead to death. As a result, routine monitoring of vitamin B12 levels is likely to be beneficial for the early detection and treatment of metabolic vitamin B12 deficiency, as well as the prevention of heart-related diseases.

Incidence and determinants of hysterectomy among North Indian women: An 8-year follow-up study

Background

Despite indications of a rapid increase in the number of hysterectomies performed in India, very few studies have methodically investigated the rate and determinants of the incidence of hysterectomy. The present study aims to estimate the rate of incidence of hysterectomy and identify predictors/determinants of incident hysterectomy in a cohort of North Indian women.

Methods

In the present study, a cohort of 1,009 ever-married North Indian women (aged 30-75 years) was followed up after a median of 8.11 years. Those hysterectomized at the baseline (63) were excluded; and of the rest 946 participants, 702 (74.2%) could be successfully followed-up. During the baseline assessment, data about sociodemographic variables, reproductive history, menopausal status, physiological health, and selected blood biochemicals were collected. During the end-line assessment, data about sociodemographic variables, current menopausal status, and incident hysterectomy were recorded.

Results

The overall rate of incidence of hysterectomy was found to be 11.59 per 1,000 women-years, in the study population. Interestingly, the incidence rates were found to be similar among pre- and post-menopausal women. Further, while late age at menarche was found to be negatively associated with incident hysterectomy, folate repletion and high triglyceride (TG) at the baseline were found to be positively associated.

Conclusions

High rate of incident hysterectomy in the studied population points toward the huge burden of gynecological morbidity and the unavailability of non-invasive protocols. Such a situation warrants immediate policy intervention. Further, maintaining TG and folate within normal physiological ranges may be beneficial in gynecological ailments necessitating hysterectomy.

The synthesis of fibroblast growth factor 23 is upregulated by homocysteine in UMR106 osteoblast-like cells

OBJECTIVES

Fibroblast growth factor 23 (FGF23) controls the production and degradation of biologically active vitamin D, 1,25(OH)₂D₃, and phosphate reabsorption in the kidney as a hormone synthesized by bone cells. Additional paracrine effects in other organs exist as well. As a biomarker, the FGF23 plasma concentration increases in renal and cardiovascular diseases, and is correlated with outcome. The regulation of FGF23 is incompletely understood and dependent on several factors, including oxidative stress. L-homocysteine is an amino acid produced in methionine metabolism, and can be converted into further metabolites depending on the availability of vitamin B. Hyperhomocysteinemia is a potential cardiovascular risk factor. Our study aimed to explore whether homocysteine impacts FGF23 synthesis.

METHODS

Experiments were performed in UMR106 osteoblast-like cells. Fgf23 gene expression and FGF23 protein concentration were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Oxidative stress was determined by 2',7'-dichlorofluorescein diacetate fluorescence.

RESULTS

Homocysteine dose-dependently upregulated Fgf23 gene expression and protein synthesis. Moreover, homocysteine imposed oxidative stress on UMR106 cells. The effect of homocysteine on Fgf23 was abrogated by antioxidant ascorbic acid.

CONCLUSIONS

Homocysteine is a potent stimulator of FGF23 production, an effect at least in part mediated by oxidative stress. The homocysteine-dependent upregulation of FGF23 presumably contributes to its role as a cardiovascular risk factor.

Molecular Cytogenetic Classification of Down Syndrome and Screening of Somatic Aneuploidy in Mothers

Down Syndrome (DS) caused by trisomy 21 results in various congenital and developmental complications in children. It is crucial to cytogenetically diagnose the DS cases early for their proper health management and to reduce the risk of further DS childbirths in mothers. In this study, we performed a cytogenetic analysis of 436 suspected DS cases using karyotyping and fluorescent in situ hybridization. We detected free trisomies (95.3%), robertsonian translocations (2.4%), isochromosomes (0.6%), and mosaics (1.2%). We observed a slightly higher incidence of DS childbirth in younger mothers compared to mothers with advanced age. We compared the somatic aneuploidy in peripheral blood of mothers having DS children (MDS) and control mothers (CM) to identify biomarkers for predicting the risk for DS childbirths. No significant difference was observed. After induced demethylation in peripheral blood cells, we did not observe a significant difference in the frequency of aneuploidy between MDS and CM. In conclusion, free trisomy 21 is the most common type of chromosomal abnormality in DS. A small number of DS cases have translocations and mosaicism of chromosome 21. Additionally, somatic aneuploidy in the peripheral blood from the mother is not an effective marker to predict DS childbirths.

Methylenetetrahydrofolate Reductase Gene C677T Polymorphism-Dietary Pattern Interaction on Hyperhomocysteinemia in a Chinese Population: A Cross-Sectional Study

Background and aim: Hyperhomocysteinemia (Hhcy) has been recognized as a risk factor of several chronic diseases. There is accumulating evidence that both genetic and dietary factors had a notable impact on the risk of Hhcy. The present study aims to investigate the interaction effect on Hhcy between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and dietary intake.

Methods: Data were collected in a cross-sectional survey conducted in China; 3,966 participants with complete information on sociodemographic characteristics, anthropometric measurements, and dietary intake were included in the analyses. Dietary patterns were identified by factor analysis combined with cluster analysis. Blood samples were collected and MTHFR C677T genotypes were tested. Both the multiplicative statistical model and the additive model were conducted to investigate the interactive effects.

Results: Proportions of MTHFR C677T genotypes among participants were 29.2% for TT, 47.4% for CT, and 23.4% for CC. Three dietary patterns were identified, namely, the balanced pattern, the snack pattern, and the high-meat pattern. Compared with the balanced pattern, the other two patterns were associated with an elevated risk of Hhcy [the snack pattern: odds ratio (OR) 1.2, 95% confidence interval (CI) 1.0–1.5; the high-meat pattern: OR 1.3, 95% CI 1.1–1.6] after adjustment for age group, gender, residential region, and MTHFR C677T genotypes. A multiplicative interaction between the high-meat pattern and MTHFR 677TT genotype was observed, and synergistic effects between both the snack pattern and the high-meat pattern with MTHFR 677TT were identified.

Conclusion: Our results indicated that MTHFR C677T polymorphism and dietary patterns had interactive effects on Hhcy among the Chinese population. Subsequent targeted and appropriate dietary guidelines should be recommended for high-risk populations or patients of Hhcy carrying specific genotypes.

Hyperhomocysteinemia and low vitamin B12 are associated with the risk of early pregnancy loss: A clinical study and meta-analyses

One-carbon metabolism is crucial for the maintenance of healthy pregnancy and alterations in this pathway have been associated with various pregnancy-related complications. Therefore, the present study was conducted to test the hypothesis that the altered folic acid, vitamin B12 and homocysteine levels are associated with the risk of early pregnancy loss (EPL). Plasma folic acid, vitamin B12 and homocysteine levels were analyzed in 83 females with EPL and 70 healthy pregnant females in their first trimester. Further, meta-analyses of folic acid, vitamin B12 and homocysteine were also performed involving various eligible studies. Results from our case-control study and meta-analysis showed that folic acid deficiency is not associated with the risk of EPL. On the other hand, low vitamin B12 and hyperhomocysteinemia were individually found to be significant risk factors for EPL in the present study (P < .01, P < .05, respectively) and meta-analysis as well (P < .001, P < .05, respectively). Vitamin B12 deficiency in combination with hyperhomocysteinemia was a more serious risk factor for EPL (Odds Ratio = 4.98, P = 0.002). Therefore, we conclude that vitamin B12 deficiency and elevated homocysteine levels are independent risk factors for EPL, and of higher risk when combined. The assessment of vitamin B12 and homocysteine levels may serve as a good screening marker for EPL risk.

Key Characteristics of Nitrous Oxide-Induced Neurological Disorders and Differences Between Populations

Background: Nitrous oxide (N₂O), commonly known as laughing gas, is inhaled recreationally because it produces the feelings of euphoria and freedom from pain. The risk of neurological dysfunction secondary to N₂O abuse and its clinical diagnosis are, however, not yet sufficiently recognized, especially in China. Here, we have summarized the key clinical characteristics of N₂O-induced neurological disorders.

Materials and Methods: We recruited 20 patients with N₂O-induced neurological disorders and analyzed their clinical features, laboratory data, magnetic resonance imaging and electromyography. We also carried out a literature review and compared 99 previously reported patients with our case series to confirm our results. Subgroup analysis was performed to explore the difference in demographical and clinical characteristics of N₂O abuse between Asian and non-Asian patients.

Results: The most common initial symptoms of N₂O-induced neurological disorders were weakness and/or paresthesia. Most patients presented with myelopathy and/or peripheral neuropathy. The most commonly involved segment of the spinal cord was the cervical spinal cord, extending over 4–6 vertebral levels, but more than half of the patients with myelopathy had no sensory change at the corresponding spinal level. Homocysteine was found to be the most sensitive and practical indicator for diagnosis. Subgroup analysis showed that the Asian patients (median: 22.0 years old, Q1–Q3:19.0–26.0 years old) with N₂O abuse were younger than non-Asian patients [26.0 (22.3–31.0) years old, P = 2.8 × 10⁻⁴]. The incidence of myelopathy combined with peripheral neuropathy was significantly higher in Asian patients than in non-Asian patients, who had myelopathy or peripheral neuropathy (P = 2 × 10⁻⁵).

Conclusions: Key clinical characteristics of N₂O abuse are longitudinally extensive cervical myelopathy and peripheral neuropathy. Recognition of these traits in young people in the age group of 20–30 years will provide important guidance for accurate diagnosis of neurological disease associated with N₂O abuse. The clinical manifestations differ in Asian patients and non-Asian patients.

Trends of folate, vitamin B12 , and homocysteine levels in different trimesters of pregnancy and pregnancy outcomes

OBJECTIVE

To evaluate the effect of folate and vitamin B₁₂ levels on pregnancy progression and outcomes.

METHODS

The present study is a prospective follow up study of 100 pregnant women. Biochemical investigations (plasma homocysteine, folate, and vitamin B₁₂ levels) were performed on all pregnant women in first, second, and third trimesters. Nonparametric tests were used to compare the differences in median levels and odds ratio analysis for the assessment of the risk between the selected biomarkers and adverse pregnancy progression and outcomes.

RESULTS

The pregnant women at their first antenatal care visit were found to be predominantly folate replete (97%) and vitamin B₁₂ deficient (60%). Hyperhomocysteinemia in first and second trimesters was found to pose more than 3-fold increased risk for adverse pregnancy outcomes (P = .006 and .0002, respectively). Low birth weight (LBW) was found to be the most common adverse pregnancy outcome (52%), and was significantly associated with vitamin B₁₂ deficiency in the first and second trimesters (82%, P < .0001; 71.4%, P = .04, respectively).

CONCLUSION

The vitamin B₁₂ deficiency is more common among Indian pregnant women as compared to folate deficiency. Hyperhomocysteinemia is an independent risk factor for pregnancy complications. Vitamin B₁₂ deficiency in first and second trimesters is associated with LBW babies.

Can the genetic polymorphisms of the folate metabolism have an influence in the polycystic ovary syndrome?

OBJECTIVE

To investigate the association of the genetic variants of the folate metabolism genes (MTHFR C677T; MTHFR A1298C; MTR A2756G; MTRR A66G and RFC-1 A80G) with the development of polycystic ovary syndrome (PCOS).

SUBJECTS AND METHODS

This study included 203 women (99 women with PCOS and 104 controls). The genotyping was performed by PCR-RFLP. Chi-squared test and multiple logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the SNPstat program. The results were presented in odds ratio (OR) and confidence interval of 95% (CI-95%), with a significance level of 5% (p ≤ 0.05).

RESULTS

The genotypic distribution of the RFC-1 A80G polymorphism showed significant difference between the two groups, showing that the heterozygous genotype (AG genotype) was most frequent in controls. The polymorphic homozygous (GG genotype) of MTRR A66G polymorphism were most frequent in controls. The T-C haplotype MTHFR C677T and A1298C polymorphisms were more frequent in the control group (OR = 0.19; CI 95% - 0.04 to 0.93 e p = 0.042). The multivariate analysis evidenced that family history of PCOS was more frequent in the PCOS group (OR = 3.29; CI 95% - 1.48 to 7.31; p = 0.003).

CONCLUSION

In our casuistry, the polymorphic homozygous of MTRR A66G polymorphism gene and heterozygous of RFC-1 A80G polymorphism gene, the haplotype T-C C677T and A1298C polymorphisms of MTHFR gene, can be associated with protective factors for the disease.

Association of vitamin B12 mediated hyperhomocysteinemia and methylenetetrafolate reductase (C677T) gene polymorphism with cognitive impairment: A population based study from North India

The present study attempts to understand the association of homocysteine, vitamin B12, folate, and MTHFR C677T gene polymorphism with cognitive impairment (CI) among 808 individuals of either sex (aged 30-70 years) from a largely vegetarian, mendelian population of North India. Biochemical and genetic analyses were done using standard protocols. Results indicate that 34.3% of the subjects had mild CI, 28.7% moderate CI and 0.2% were having severe CI. Hyperhomocysteinemia was found to be a significant risk factor for moderate/severe CI. Both CT genotype and T allele of MTHFR C677T gene polymorphism were found to pose significant decreased risk for CI.

Metabolic distress in lipid & one carbon metabolic pathway through low vitamin B-12: a population based study from North India

Background

Dyslipidemia and hyper-homocysteinemia are the major independent risk factors of cardio vascular disease. Deficiency of folate and vitamin B-12 are associated with both hyper-homocysteinemia and dyslipidemia. The aim of the study is to evaluate the relationship of homocysteine and its associated dietary determinant levels (Folate and Vitamin B-12) with lipids and obesity parameters (WC, BMI, WHR) in North Indian population.

Methods

The participants were recruited under a major government funded project through household survey covering 15 villages of Haryana, India. Participants were both males and females, between age group 30–65 years, from a north Indian community. Initially 1634 individuals were recruited, of which 1374 were considered for analysis as they were not found to be on any kind of medication for high blood pressure, CAD, diabetes or any other disorder, and had no missing data. 5 mL of intravenous blood sample was collected after obtaining written informed consent from the participants. Homocysteine, folate and vitamin B12 levels were estimated through Immulite 1000 by chemi-luminescence technique. Triglyceride, total cholesterol and HDL-C were estimated by spectrophotometry technique using commercial kits. The values for LDL and VLDL were calculated using Friedwald’s equation. Height, weight, waist circumference (WC), hip circumference (HC) was measured over light clothing. Statistical analysis for data was performed using SPSS 16.0 version.

Results

All the lipid indices, except HDL, showed a trend of negative correlation with homocysteine after controlling for confounders, though not significant. No association was found between obesity (WC, BMI, WHR) and homocysteine in the present study. Vitamin B-12 deficiency was significantly associated with both hyper-homocysteinemia and low HDL. Folate was found to have significantly reduced risk for high TC & LDL.

Conclusions

The “hcy-lipid” hypothesis does not seem to be complementing in the present studied population. The population is vulnerable to severe under-nutrition due to the association of vitamin B-12 with HDL, leading to metabolic disturbance in both the pathways; lipid and one carbon metabolic pathway. Co-factors such as ethnicity, cultural practices, and lifestyle & dietary habits must be considered while making public health policies to control diseases.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0748-y) contains supplementary material, which is available to authorized users.

Association of Kaphaja and Kapha-Pittaja Prakriti and methylenetetrahydrofolate reductase C677T allele with type 2 diabetes

Background and Objectives:

Type 2 diabetes is a multifactorial disorder that results from the interaction between genetic predisposition and environmental factors. Different Prakriti (body constitution) individuals have different susceptibility for the diseases, and this Prakriti is determined by both genetic and environmental factor. This study was undertaken to determine the association status of Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C with type 2 diabetes and Prakriti.

Materials and Methods:

After informed consent, 54 patients with type 2 diabetes and 56 individuals as normal controls were analyzed. Their constitution and pathological data were collected and MTHFR C677T and A1298C genotypes were determined.

Results:

Kapha/Kapha-Pittaja Prakriti were associated and found to be strong risk factors (Chi-square test = 39.67, P < 0.00001, odds ratio [OR] = 16.133, 95% confidence interval [CI] = 6.32–41.20) for type 2 diabetes. MTHFR C677T was associated (Chi-square test = 7.743, P = 0.02) with type 2 diabetes where the major CC genotype was found to be a risk for type 2 diabetes (OR = 3.78, 95% CI = 1.14–12.45). A1298C was not associated with type 2 diabetes (Chi-square test = 2.264, P = 0.322). None of the Prakriti was associated with C677T and A1298C variants.

Interpretation and Conclusion:

In the present study, an extremely strong association between Prakriti (Kaphaja/Kapha-Pittaja) and type 2 diabetes (P < 0.00001) was detected. The present study gives a strong clue for the association of Prakriti (body constitutional) and clinical phenotype.

Methylenetetrahydrofolate Reductase Gene-specific Methylation and Recurrent Miscarriages: A Case- Control Study from North India

Aim:

This study aimed to understand the association of gene-specific methylation of the promoter region of methylenetetrahydrofolate reductase (MTHFR) in the causation of recurrent miscarriages (RMs) both independently and also in light of MTHFR C677T polymorphism, hyperhomocysteinemia, folate, and Vitamin B12 deficiency.

Settings and Design:

This was a hospital-based, case–control, observational study.

Methods:

The proposed study included a total of 85 RM cases and 121 nonpregnant controls. Biochemical (homocysteine, folate, and Vitamin B12) investigations, MTHFR polymorphism (C677T), and MTHFR allele-specific methylation were done on all the samples.

Results:

Methylation-specific polymerase chain reaction of MTHFR gene revealed that methylated allele (single dose) was found to pose a significant 3.6-fold increased risk for RM. The degree of risk of methylated allele for RM was found to be aggravated from the normal genotype CC (2.8 folds) to CT (7.5 folds) individuals. Vitamin B12 deficiency and folate repletion were found to be posing an increased risk in association with methylated allele for recurrent miscarriages as compared to the respective controls.

Conclusion:

Recurrent miscarriage cases were found to be hypermethylated with respect to MTHFR gene-specific methylation as compared to the controls. High prevalence of folate repletion causing imbalance between folate and Vitamin 12 levels may lead to hypermethylation among recurrent miscarriage cases. The present study highlights the significance of the epigenetic mechanisms in the causation of the recurrent miscarriages.

The study of association between reduced folate carrier 1 (RFC1) polymorphism and non-syndromic cleft lip/palate in Iranian population

Introduction: Cleft lip/palate is one of the most common congenital defects and is supposed to have multifactorial etiology, including a complex interaction between genetics and environment. Reduced folate carrier 1 (RFC1) gene takes part in folate transportation within the cells. In this study, the association of A80G polymorphism in the RFC1 gene with the non-syndromic cleft lip/palate (nsCL/P) was investigated in Iranian infants for the first time. Methods: In this case-control survey, 122 Iranian infants with nsCL/P and 164 healthy infants were investigated for RFC1 polymorphism by PCR and RFLP methods. The results were statistically compared with control group, odds ratios with 95% CI were estimated by univariate and multivariate logistic regression model and a P <0.05 was considered statistically significant. Results: The RFC1 G allele was significantly higher (P=0.001; OR=7, 95% CI: 4.7-10.2) in the cases (60.3%) compared with the controls (17.9%). Not only the RFC1 AG genotype was significantly higher (P<0.001; OR=44, 95% CI: 14.6-133) in cases (67.8%) than the controls (27.4%), but also GG genotype (P<0.001; OR=85, 95% CI: 20.5-352) was much higher in cases (26.4%) than the controls (4.3%). Conclusion: Our study indicated that the RFC1 (A80G) polymorphism was associated with the nsCL/P in Iranian population. Moreover, 80GG homozygosity was significant in the cases. The presence of G allele can be considered as a risk factor for the nsCL/P. Infants with the GG and AG genotypes were more prone to cleft lip/palate as compared to the AA ones. This finding emphasizes the role of RFC1 gene and the intracellular levels of folate.

Distribution of MTHFR C677T Gene Polymorphism in Healthy North Indian Population and an Updated Meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of folate pathway. Several polymorphisms were reported in MTHFR gene but C677T polymorphism is most studied and it has been reported to be risk factor for several diseases/disorders. The present study was designed to explore the frequency of MTHFR C677T polymorphism in North Indian healthy population. In addition to this a meta-analysis of published articles was also performed to estimate the global prevalence of MTHFR C677T polymorphism. A total of 1000 unrelated healthy subjects were selected for MTHFR C677T polymorphism analysis. Different databases were searched for eligible articles. Prevalence proportion with 95 % CI was used to determine global prevalence of T allele and TT genotype. Meta-analysis was performed by Open meta-analyst. In 1000 blood samples analyzed, the frequency of T allele and TT genotype was 11 and 1 % respectively. Results of the meta-analysis showed that the global prevalence of T allele and TT genotype were 24.0 % (95 % CI 21.7-26.5) and 7.7 % (95 % CI 6.5-8.9) respectively. In sub-group meta-analysis, the lowest frequency of T allele was found in Africans (10.3 %; 95 % CI 3.8-16.8), and highest in Europeans (34.1 %; 95 % CI 31.9-36.3). The frequency of T allele in the North India is 11 %. The results of the meta-analysis showed that the frequency of the T allele and the TT genotype of C677T is highest in the Caucasian population.

Association between polymorphisms in folate metabolism genes and maternal risk for Down syndrome: A meta-analysis

Previous studies have focused on the association between polymorphisms of the genes involved in folate metabolism and Down syndrome (DS); however, the results remain inconclusive. The present meta-analysis was conducted to assess the association between RFC-1 A80G/MTR A2756G/CBS 844ins68 polymorphisms and the maternal risk of DS. Published studies were retrieved from PubMed, Embase, China National Knowledge Infrastructure and Chinese Biomedicine databases. Pooled odds ratios (ORs) with 95% confidence interval (CIs) were calculated using the fixed- or random-effects model. Additionally, test of heterogeneity, cumulative meta-analysis, sensitivity analysis and assessment of bias were also performed. Finally, 11, 11 and 6 studies were deemed eligible for meta-analyses of RFC-1 A80G, MTR A2756G and CBS 844ins68, respectively. A significant association between RFC-1 A80G polymorphism and DS risk was observed for G vs. A (OR=1.19, 95% CI: 1.004-1.40, P=0.04) and the recessive model (OR=1.28, 95% CI: 1.05-1.56, P=0.01). In the stratified analysis by source of control or sample size, a significantly increased risk was observed among hospital-based studies and large-sample groups (>200 subjects), respectively. In addition, the cumulative meta-analysis of the RFC-1 A80G variant revealed a trend toward an association as the amount of data increased. However, for the MTR A2756G and CBS 844ins68 polymorphisms, no obvious association was found for all genetic models. In summary, the present meta-analysis demonstrated that RFC-1 A80G, but not MTR A2756G or CBS 844ins68, was considered as a maternal risk factor for DS in the offspring.

Association of MTHFR, SLC19A1 Genetic Polymorphism, Serum Folate, Vitamin B12 and Hcy Status with Cognitive Functions in Chinese Adults

Background/Aim: Studies have indicated a relationship between either gene polymorphism or in vivo B vitamins’ nutritional status with cognition in the elderly. However, the combined effects of MTHFR and SLC19A1gene polymorphism with serum folate and vitamin B₁₂ levels on cognition in Chinese adult population remain unclear. Methods: Demographic information of 426 Chinese adults aged from 55 to 90 were collected by a well designed self-administered questionnaire. The Montreal Cognitive Assessment test was utilized to evaluate the cognition status of the participants. MTHFR and SLC19A1 genotyping was analyzed using polymerase chain reaction-ligase detection reaction (PCR- LDR) method. Serum folate, vitamin B₁₂ and homocysteine (Hcy) levels were detected by commercial assay kits. Pearson’s correlation was used for data analyses and statistical significance was set at p < 0.05. Results: Serum Hcylevels demonstrated a negative correlation with serum folate (r = −0.301) and vitamin B₁₂ (r = −0.292) levels. The negative correlation found between serum Hcy levels and attention ability was observed in all 426 studied subjects (r = −0.122). Subjects with MTHFR 677 T/T and 1298 A/A genotypes demonstrated a higher serum Hcy levels (p < 0.05). Carriers of MTHFR (1298 A/C + C/C and 1793 G/A) and SLC19A1 80 G/G genotypes showed lower abstraction and delayed memory ability, respectively (p < 0.05). Subjects with MTHFR 1793 G/A genotype along with low serum folate concentration demonstrated the lowest name and orientation abilities. The effects of MTHFR 1793 G/A genotype on cognitive performance were dependent on the status of serum vitamin B₁₂. Conclusion: Cognition of adults was associated with MTHFR, SLC19A1 gene polymorphism and serum Hcy levels. This study clearly establishes a combined effect of MTHFR gene polymorphism and serum B vitamins levels on cognition in Chinese adults.

Choline metabolic pathway gene polymorphisms and risk for Down syndrome: An association study in a population with folate-homocysteine metabolic impairment

BACKGROUND/OBJECTIVES

Choline is an essential nutrient involved in one-carbon metabolism, but its role in mechanisms underlying meiotic non-disjunction is poorly known. The relationship between folate-homocysteine metabolic pathway gene polymorphism and Down syndrome (DS) risk has been widely analyzed, but there are limited reports on its correlation with choline metabolism. In the present case-control association study, we investigated the relationship of three single-nucleotide polymorphisms (SNPs) (phosphatidylethanolamine N-methyltransferase (PEMT) rs12325817, choline dehydrogenase (CHDH) rs12676 and homocysteine methyltransferase (BHMT) rs3733890) of choline metabolism with risk for DS.

SUBJECT/METHODS

Genotyping of 228 mothers of a down syndrome child (DSM) and 200 control mothers (CMs) for all SNPs was performed by PCR coupled with restriction fragment length polymorphism method.

RESULTS

A significantly increased risk for BHMT +742AA genotype with an odds ratio of 4.96 (95% confidence interval (CI): 1.66-14.88, P=0.0036) was observed. For PEMT rs12325817 and CHDH rs12676, no significant difference in allelic and genotypic frequencies was observed. In genotypic combination analysis considering PEMT -744GG/CHDH +432GG/BHMT +742GG as the reference combination, PEMT -744GC/CHDH +432GG/BHMT +742GG genotypic combination was significantly higher in DSM compared with that in CMs with an odds ratio of 2.061 (95% CI: 1.10-3.86, P=0.0342). We also observed an epistatic interaction between methylenetetrahydrofolate reductase (MTHFR) rs1801133 and choline metabolic pathway gene variants.

CONCLUSIONS

Our findings indicate impaired choline metabolism showing a greater risk for DS, especially in a population associated with homocysteine-folate impairment. Further studies are required to confirm our findings.

Homocysteine Metabolism Gene Polymorphisms (MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) Jointly Elevate the Risk of Folate Deficiency

Folate deficiency is strongly associated with cardiovascular disease. We aimed to explore the joint effect of the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, and methionine synthase reductase (MTRR) A66G polymorphisms on folate deficiency in a Chinese hypertensive population. A total of 480 subjects aged 28–75 were enrolled in this study from September 2005–December 2005 from six hospitals in different Chinese regions. Known genotypes were detected by PCR-RFLP methods and serum folate was measured by chemiluminescence immunoassay. Our results showed that MTHFR 677TT and MTR 2756AG + GG were independently associated with a higher risk of folate deficiency (TT vs. CC + CT, p < 0.001 and AG + GG vs. AA p = 0.030, respectively). However, the MTHFR A1298C mutation may confer protection by elevating the serum folate level (p = 0.025). Furthermore, patients carrying two or more risk genotypes showed higher odds of folate deficiency than null risk genotype carriers, especially those carrying four risk genotypes. These findings were verified by generalized multifactor dimensionality reduction (p = 0.0107) and a cumulative effects model (p = 0.001). The results of this study have shown that interactions among homocysteine metabolism gene polymorphisms lead to dramatic elevations in the folate deficiency risk.

Role of folate-homocysteine pathway gene polymorphisms and nutritional cofactors in Down syndrome: A triad study

STUDY QUESTION

Do gene-gene and gene-environment interactions in folate-homocysteine (Hcy) pathway have a predisposing role for Down syndrome (DS)?

SUMMARY ANSWER

The study provides evidence that in addition to advanced age, maternal genotype, micronutrient deficiency and elevated Hcy levels, individually and in combination, are risk factors for Down syndrome.

WHAT IS KNOWN ALREADY

Polymorphisms in certain folate-Hcy-pathway genes (especially the T allele of MTHFR C677T), elevated Hcy and poor folate levels in mothers during pregnancy have been shown to be risk factors for Down syndrome in certain Asian populations (including the eastern region of India), while the same SNPs are not a risk factor in European populations. This conflicting situation alludes to differential gene-environment (nutrition) interactions in different populations which needs to be explored.

STUDY DESIGN, SIZE, DURATION

Between 2008 and 2012, 151 Down syndrome triads and 200 age-matched controls (Control mothers n = 186) were included in the study. Seven polymorphisms in six genes of folate-Hcy metabolic pathway, along with Hcy, cysteine (Cys), vitamin B12 (vit-B12) and folate levels, were analysed and compared among the case and control groups.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Genotyping was performed by the PCR-RFLP technique. Levels of homocysteine and cysteine were measured by HPLC while vitamin B12 and folate were estimated by chemiluminescence.

MAIN RESULTS AND THE ROLE OF CHANCE

We demonstrate that polymorphisms in the folate-Hcy pathway genes in mothers collectively constitute a genotypic risk for DS which is effectively modified by interactions among genes and by the environment affecting folate, Hcy and vitamin B12 levels. The study also supports the idea that these maternal risk factors provide an adaptive advantage during pregnancy supporting live birth of the DS child.

LIMITATIONS AND REASONS FOR CAUTION

Our inability to obtain genotype and nutritional assessments of unaffected siblings of the DS children was an important limitation of the study. Also, its confinement to a specific geographic region (the eastern part) of India, and relatively small sample size is a limitation. A parallel investigation on another population could add greater authenticity to the data.

WIDER IMPLICATIONS OF THE FINDINGS

For mothers genetically susceptible to deliver a DS child (particularly in South Asia), peri-conceptional nutritional supplementation and antenatal care could potentially reduce the risk of a DS child. Additionally, nutritional strategies could possibly be used for better management of the symptoms of DS children.

STUDY FUNDING/COMPETING INTERESTS

The work is funded through Programme support for Genetic disorders by Department of Biotechnology, Government of India to R.R. The authors declare no conflict of interest.

Maternal risk for down syndrome and polymorphisms in the promoter region of the DNMT3B gene: a case-control study

BACKGROUND

Epigenetic changes leading to improper methylation of the pericentromeric region of chromosome 21 may contribute to the nondisjunction of this chromosome. Polymorphisms in the DNA Methyltransferase 3B (DNMT3B) gene, one of the crucial gene of the folate metabolism, affects the activity of the enzyme and increases the susceptibility of nondisjunction in mothers of Down syndrome children (MDS).

METHODS

Considering this hypothesis we investigated the association of single nucleotide polymorphisms in the promoter region of the DNMT3B gene (rs1569686 -579G>T; rs2424913 -149C>T) with a predisposition of mothers to deliver a Down syndrome (DS) child. The study was performed on DNA samples from 150 MDS and 172 control mothers. Transmission disequilibrium tests were performed on 103 DS trio families. Genotyping was done using a polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

With respect to the single nucleotide polymorphisms studied, no significant difference was observed in the genotypes and alleles frequency distributions between MDS and control mothers. The frequency of the DNMT3B-579G allele was, respectively, 0.34 in MDS and 0.33 in control mothers whereas the frequency of the DNMT3B-149C allele was respectively 0.31 in MDS and 0.26 in control mothers. No significant deviation in genotypic combinations as well as in transmission disequilibrium tests analysis was observed. However, a strong linkage disequilibrium was observed with significant differences in the distribution of G-T and G-C haplotypes among case and control mothers.

CONCLUSION

Although the above studied polymorphisms of DNMT3B may not be an independent risk factor it might be possible that certain allelic combinations (G-T) are. This finding suggests that DNMT3B might be a maternal risk factor for DS in our Indian cohort. Replication studies are required to confirm these findings.

Haemoglobinopathies in eastern Indian states: a demographic evaluation

Haemoglobinopathies are a leading cause of child mortality worldwide, although with a variable geographical incidence. A reliable estimate of prevalence of the disease is necessary for reducing its burden. However, most studies in India are either hospital based or from certain regions of the country and hence may not realistically reflect the disease burden. The eastern Indian states of Bihar, Chhattisgarh and Jharkhand and eastern region of Uttar Pradesh, which comprise ~25 % population of the country, are poorly studied with respect to haemoglobinopathies. The present study, conducted on 1,642 individuals from this region, shows a frequency of 3.4 % for β-thalassaemia trait (BTT), 3.4 % for sickle cell haemoglobin trait (HbS)/haemoglobin E trait (HbE) and 18 % for α-globin defects. While BTT mutations are distributed rather uniformly across the region, HbS occurs only in Chhattisgarh and Jharkhand, the regions rich in tribal populations. The frequency of α-gene mutation is strikingly high, occurring even in individuals with normal blood count, in tribal as well as non-tribal groups. The mutation spectrum of BTT is also distinct since the common mutations, IVS1-1 (G-T) and 619 bp del, are absent while CD15 (G-A) is the second most frequent. The HbA2 level in the suspected cases is strikingly low. We demonstrate association of the low HbA2 level with vitamin B12 and folate deficiency in this cohort. Thus, the present report besides providing an estimate of the carrier frequency of β-thalassaemia traits also confirms high prevalence of α-gene defects and regional heterogeneity in distribution of HbS in the eastern parts of India.

MTHFR C677T predisposes to POAG but not to PACG in a North Indian population: a case control study

Hyperhomocysteinemia induced by the C677T genetic variant in MTHFR (methylenetetrahydrofolate reductase) has been implicated in neuronal cell death of retinal ganglion cells (RGC), which is a characteristic feature of glaucoma. However, association of MTHFR C677T with glaucoma has been controversial because of inconsistent results across association studies. Association between MTHFR C677T and glaucoma has not been reported in Indian population. Therefore, with a focus on neurodegenerative death of RGC in glaucoma, the current study aimed to investigate association of MTHFR C677T with Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG) in a North Indian population. A total of 404 participants (231 patients and 173 controls) were included in this study. Genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. A few random samples were also tested by direct sequencing. Genotypic and allelic distributions of the POAG and PACG cohorts were compared to that of controls by chi-square test and odds ratios were reported with 95% confidence intervals. Genotypic and allelic distributions between POAG cases and controls were significantly different (p = 0.03 and p = 0.01 respectively). Unlike POAG, we did not find significant difference in the genotypic and allelic distributions of C677T between PACG cases and controls (p>0.05). We also observed a higher proportion of TT associated POAG in females than that in males. However, this is a preliminary indication of gender specific risk of C677T that needs to be replicated in a larger cohort of males and females. The present investigation on MTHFR C677T and glaucoma reveals that the TT genotype and T allele of this polymorphism are significant risk factors for POAG but not for PACG in North Indian population. Ours is the first report demonstrating association of MTHFR C677T with POAG but not PACG in individuals from North India.

Epigenetic silencing of CXCR4 promotes loss of cell adhesion in cervical cancer

In the network of chemokine signaling pathways, recent reports have described the SDF-1α/CXCR4 axis and its role in cancer progression and metastasis. Interestingly, we found downregulation of CXCR4 at both transcript and protein level in cervical cancer cell lines and primary tumors. We also found CXCR4 promoter hypermethylation in cervical cancer cell lines and primary biopsy samples. DNA hypomethylating drug 5-AZA-2′-deoxycytidine and histone deacetylase inhibitor Trichostatin A treatments in cell lines reactivate both CXCR4 transcription and protein expression. Cell adhesion assay demonstrated that autocrine SDF-1α promotes the loss of cell adhesion while paracrine SDF-1α predominantly protects the normal cervical cells from loss of cell adhesion. Cervical cancer cell line C-33A having increased expression of CXCR4 after TSA treatment showed increased cell adhesion by paracrine source of SDF-1α in comparison to untreated C-33A. These findings demonstrate the first evidence that epigenetic silencing of CXCR4 makes the cells inefficient to respond to the paracrine source of SDF-1α leading to loss of cell adhesion, one of the key events in metastases and progression of the disease. Our results provide novel insight of SDF-1α/CXCR4 signaling in tumor microenvironment which may be promising to further delineate molecular mechanism of cervical carcinogenesis.

Low birthweight (LBW) and neonatal hyperbilirubinemia (NNH) in an Indian cohort: association of homocysteine, its metabolic pathway genes and micronutrients as risk factors

Background & Aims

Indian subcontinent has the highest child mortality rates along with a very high frequency of low birthweight (LBW). Folate and vitamin B12 (Vit-B12) are necessary during foetal development and their deficiency prevalence in Indians is very high. The objective of the present paper is to assess whether foetal homocysteine (Hcy)/folate metabolic pathway genes, their cofactors and homocysteine level independently (or collectively) predispose children to Low birth weight.

Methods

Cord blood was collected for the study. Frequency of 5 SNPs in 4-Hcy-pathway genes, and levels of Hcy, Vit-B12 and folate were evaluated.

Results

Of the 421 newborns recruited for the study, 38% showed low birth weight (<2.5kg) and 16% were preterm babies. 101 neonates developed neonatal hyperbilirubinemia (NNH). High prevalence of Vit-B12 (65%) and folate (27%) deficiency was observed in newborns along with hyperhomocystinemia (hypHcy-25%). Preterm delivery, micronutrient deficiency, hypHcy and MTHFR 677T SNP are associated as risk factor while G allele of TCN2 C776G is protective against LBW. MTHFR 677T allele and folate deficiency are also independent risk factors for NNH.

Conclusion

We record the highest incidence of Vit-B12, folate deficiency and elevated Hcy levels, of all the studies so far reported on neonates. These together with MTHFR 677T are potential risk factors for LBW. Association of impaired folate/Hcy metabolism with NNH is reported for the first time and the possible way of interaction is discussed. It appears that proper nutritional management during pregnancy would reduce the risk of complex clinical outcomes.

Hyperhomocysteinemia induces cardiac injury by up-regulation of p53-dependent Noxa and Bax expression through the p53 DNA methylation in ApoE(-/-) mice

Hyperhomocysteinemia (HHcy) is a risk factor for cardiovascular disease and has a strong correlation with heart failure. However, the effects of HHcy on cardiac tissue remain less well understood. To elucidate the role of p53-dependent apoptosis in HHcy-induced cardiac injury, we fed ApoE(-/-) mice with high methionine diet to establish HHcy model. Serum Hcy, cardiac enzymes, and lipids were measured. The protein levels of Noxa, DNMT1, caspases-3/9, and p53 were determined by enzyme-linked immunosorbent assay. Bcl-2 and Bax proteins were detected by immunohistochemistry staining. S-adenosyl methionine and S-adenosyl homocysteine concentrations were determined by high-performance liquid chromatography. The mRNA levels of p53 and DNMT1 were analyzed by real-time polymerase chain reaction (PCR) and the methylation levels of p53 were analyzed by nested methylation-specific-PCR. Our data showed that the concentrations of serum Hcy and lipids were increased in Meth group compared with the N-control group, which indicated that the model was established successfully. The expression levels of p53 and Noxa were increased in Meth group, while the methylation status of p53 was hypomethylation. The activities of caspase-3/9 were increased in Meth group compared with the N-control group. In addition, immunohistochemistry staining showed that the expression of Bax was significantly increased in Meth and Meth-F group compared with the N-control group. In summary, HHcy induces cardiac injury by up-regulation of p53-dependent pro-apoptotic related genes Noxa and Bax, while p53 DNA hypomethylation is a key molecular mechanism in pathological process induced by HHcy.

Detailed analysis of gene polymorphisms associated with ischemic stroke in South Asians

The burden of stroke is disproportionately high in the South Asian subcontinent with South Asian ethnicity conferring a greater risk of ischemic stroke than European ancestry regardless of country inhabited. While genes associated with stroke in European populations have been investigated, they remain largely unknown in South Asians. We conducted a comprehensive meta-analysis of known genetic polymorphisms associated with South Asian ischemic stroke, and compared effect size of the MTHFR C677T-stroke association with effect sizes predicted from homocysteine-stroke association. Electronic databases were searched up to August 2012 for published case control studies investigating genetic polymorphisms associated with ischemic stroke in South Asians. Pooled odds ratios (OR) for each gene-disease association were calculated using a random-effects model. We identified 26 studies (approximately 2529 stroke cases and 2881 controls) interrogating 33 independent genetic polymorphisms in 22 genes. Ten studies described MTHFR C677T (108 with TT genotype and 2018 with CC genotype) -homocysteine relationship and six studies (735 stroke cases and 713 controls) described homocysteine-ischemic stroke relationship. Risk association ORs were calculated for ACE I/D (OR 5.00; 95% CI, 1.17–21.37; p = 0.03), PDE4D SNP 83 (OR 2.20; 95% CI 1.21–3.99; p = 0.01), PDE4D SNP 32 (OR 1.57; 95% CI 1.01–2.45, p = 0.045) and IL10 G1082A (OR 1.44; 95% CI, 1.09–1.91, p = 0.01). Significant association was observed between elevated plasma homocysteine levels and MTHFR/677 TT genotypes in healthy South Asians (Mean difference (ΔX) 5.18 µmol/L; 95% CI 2.03–8.34: p = 0.001). Our results demonstrate that the genetic etiology of ischemic stroke in South Asians is broadly similar to the risk conferred in Europeans, although the dataset is considerably smaller and warrants the same clinical considerations for risk profiling.

Vitamin B12 deficiency and hyperhomocysteinemia as correlates of cardiovascular risk factors in Indian subjects with coronary artery disease

BACKGROUND AND PURPOSE

Folate and vitamin B12 are essential components in the metabolism of homocysteine (Hcy). Hyperhomocysteinemia has been implicated in endothelial dysfunction and cardiovascular disease. However, the association of Hcy, vitamin B12, and folic acid with cardiovascular risk factors in patients with coronary artery disease (CAD) has not been studied in Indian patients. This study was conducted with the aim to evaluate the relationship of vitamin B12, folic acid, and Hcy levels with cardiovascular risk factors in subjects with known CAD.

METHODS AND SUBJECTS

Three hundred patients (216 men; 84 women; aged 25-92 years) who had CAD on angiography were included in this study consecutively. All patients were evaluated for anthropometry and cardiovascular risk factors, and blood samples were collected for biochemical, nutritional, and inflammatory markers.

RESULTS

Percentage of vitamin B12 and folate deficiency was 86.7% and 2.7%, respectively. Hyperhomocysteinemia was present in 95.3% patients. Vitamin B12 levels were significantly lower and Hcy levels were significantly higher in subjects with dyslipidemia, DM, and/or hypertension. Serum vitamin B12 was inversely associated with triglyceride and very low-density lipoprotein (VLDL) and positively with high-density lipoprotein (HDL). Hcy was positively associated with triglyceride and VLDL and negatively with HDL. Vitamin B12 was inversely correlated with inflammatory markers (high-sensitivity C-reactive protein and interleukin-6) directly related to insulin resistance whereas Hcy showed the opposite pattern.

CONCLUSIONS

Serum vitamin B12 deficiency and hyperhomocysteinemia are related with cardiovascular risk factors in Indian patients with CAD.

Polymorphisms in genes RFC-1/CBS as maternal risk factors for Down syndrome in China

PURPOSE

To explore the relationship between genetic polymorphisms in reduced folate carrier 1 (RFC-1), cystathionine b-synthase (CBS), two key genes in folate metabolism, and the risk of Down syndrome in China.

METHODS

Genomic DNA was isolated from the peripheral lymphocytes of 104 mothers born children with Down syndrome and 184 age-matched control mothers. Polymerase chain reaction and restriction-fragment length polymorphism were used to examine the polymorphisms of RFC-1 A80G, CBS T833C and the relationship between these genotypes and the risk of Down syndrome was analyzed.

RESULTS

We found that there were significant differences between RFC-1 G80G, CBS C833C polymorphisms among mothers of children with Down syndrome than among control mothers, with odds ratio of 1.51 (95 % CI 1.05-2.18), 1.53 (95 % CI 1.07-2.18) respectively. The combined presence of RFC1 mutant alleles and the CBS homozygous mutant allele (15/104) was associated with a 4.81-fold increased risk of having a child with Down syndrome (95 % CI 1.82-12.68, P = 0.0007).

CONCLUSIONS

We concluded that RFC-1 and CBS gene mutation alleles are related to Down syndrome, and women with mutation RFC-1 G80G, CBS C833C OR combined with RFC-1 A80G and CBS 833TT genotype increase the risk of Down syndrome in China.

Prevalence of MTHFR C677T and MS A2756G polymorphisms in major depressive disorder, and their impact on response to fluoxetine treatment

OBJECTIVE

To examine the prevalence of the C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene and the A2756G polymorphism of methionine synthase (MS), and their impact on antidepressant response.

METHODS

We screened 224 subjects (52% female, mean age 39 ± 11 years) with SCID-diagnosed major depressive disorder (MDD), and obtained 194 genetic samples. 49 subjects (49% female, mean age 36 ± 11 years) participated in a 12-week open clinical trial of fluoxetine 20-60 mg/day. Association between clinical response and C677T and A2756G polymorphisms, folate, B12, and homocysteine was examined.

RESULTS

Prevalence of the C677T and A2756G polymorphisms was consistent with previous reports (C/C = 41%, C/T = 47%, T/T = 11%, A/A = 66%, A/G = 29%, G/G = 4%). In the fluoxetine-treated subsample (n = 49), intent-to-treat (ITT) response rates were 47% for C/C subjects and 46% for pooled C/T and T/T subjects (nonsignificant). ITT response rates were 38% for A/A subjects and 60% for A/G subjects (nonsignificant), with no subjects exhibiting the G/G homozygote. Mean baseline plasma B12 was significantly lower in A/G subjects compared to A/A, but folate and homocysteine levels were not affected by genetic status. Plasma folate was negatively associated with treatment response.

CONCLUSION

The C677T and A2756G polymorphisms did not significantly affect antidepressant response. These preliminary findings require replication in larger samples.