C677T Variant Research Articles

The relationship between MTHFR C677T gene polymorphism and essential hypertension in a sample of an Algerian population of Oran city

BackgroundMany studies have investigated the role of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in essential hypertension (EH), but with conflicting results. AimTo determine the eventual association between 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and hypertension in a sample of Algerian population from the Oran city. MethodsA case–control study has been performed in 154 subjects including 82 hypertensives defined as subjects with elevated systolic blood pressure SBD≥140mmHg and or sustained diastolic blood pressure DBP≥90mmHg, and 72 normotensive subjects. Polymerase chain reaction (PCR) combined with restrictive fragment length polymorphism (RFLP) was used to detect the MTHFR C677T variant. ResultsWe observe no significant differences between allelic and genotypic frequencies between cases and controls for C677T polymorphism (OR=1.51, 95% CI=0.89–2.56, P=0.13). Analyses adjusted for age, sex and body mass index improved the association level, though the association was still not significant (30% vs. 22%, OR=1.75, 95% CI=0.95–3.24, P=0.07). ConclusionThis work showed that genetic polymorphism related to the MTHFR gene (C677T) is not associated with the risk of hypertension in this sample of Algerian population. Larger case–control samples are required to clearly assess the role of this genetic variant in EH.

The C677T Variant in MTHFR Modulates Associations Between Brain Integrity, Mood, and Cognitive Functioning in Old Age

BackgroundThe C677T functional variant in the methylenetetrahydrofolate reductase (MTHFR) gene leads to reduced enzymatic activity and elevated blood homocysteine levels. Hyperhomocysteinemia has been linked with higher rates of cardiovascular diseases, cognitive decline, and late-life depression. MethodsThree-dimensional magnetic resonance imaging data were analyzed from 738 individuals (aged 75.5 ± 6.8 years; 438 men, 300 women), including 173 patients with Alzheimer’s disease, 359 subjects with mild cognitive impairment, and 206 healthy older adults, scanned as part of the Alzheimer’s Disease Neuroimaging Initiative. ResultsWe found that this variant associates with localized brain atrophy, after controlling for age, sex, and dementia status, in brain regions implicated in both intellectual and emotional functioning, notably the medial orbitofrontal cortices. The medial orbitofrontal cortex is involved in the cognitive modulation of emotional processes, and localized atrophy in this region was previously linked with both cognitive impairment and depressive symptoms. Here, we report that increased plasma homocysteine level mediates the association between MTHFR genotype and lower medial orbitofrontal volumes and that these volumes mediate the association between cognitive decline and depressed mood in this elderly cohort. We additionally show that vitamin B12 deficiency interacts with the C677T variant in the etiology of hyperhomocysteinemia. ConclusionsThis study sheds light on important relationships between vascular risk factors, age-related cognitive decline, and late-life depression, and it represents a significant advance in our understanding of clinically relevant associations relating to MTHFR genotype.

The C677T variant in MTHFR modulates associations between blood-based and cerebrospinal fluid biomarkers of neurodegeneration.

The C677T functional variant in the methylene-tetrahydrofolate reductase (MTHFR) gene results in reduced enzymatic activity and elevated blood levels of homocysteine. Plasma levels of apolipoprotein E (ApoE) are negatively correlated with cerebral amyloid burden, but plasma homocysteine concentrations are associated with increased amyloid-β (Aβ) deposition in the brain. Here, we sought to determine whether associations between low plasma ApoE levels and elevated in-vivo amyloid burden were modulated by carrying the C677T variant. We tested this hypothesis in a large sample of elderly participants from the Alzheimer’s Disease Neuroimaging Initiative. We used general linear models to examine associations between plasma homocysteine concentrations, circulating ApoE levels, cerebrospinal fluid concentrations of Aβ, and their modulation by MTHFR and ApoE genotype. Age, sex, and dementia status were included as covariates in all analyses. Higher circulating levels of ApoE predicted increased cerebrospinal fluid concentrations of Aβ, indicating lower in-vivo burden, in C-allele carriers, but not in homozygotes at the C677T variant, who showed significant elevations in plasma homocysteine levels. This modulation by the MTHFR genotype did not remain significant after controlling for ApoE genotype. In T-homozygotes who do not carry the ApoE-ε4 allele, the relationship between low plasma ApoE levels and an increased risk of dementia is likely obscured by the presence of elevated plasma homocysteine. This report suggests the value of genotyping patients at the C677T functional variant when using plasma ApoE levels as a preclinical biomarker for Alzheimer’s disease.

Methylenetetrahydrofolate reductase C677T polymorphism, hypertension and risk of stroke: a prospective, nested case-control study

Background: Hyperhomocysteinemia is a risk factor for cardiovascular disease. To date, limited prospective studies have examined the joint effects of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, hyperhomocysteinemia and conventional vascular risk factors on risk of stroke and stroke death. Methods: A total of 39 165 subjects from nine communities within Anqing, Anhui Province, China were prospectively followed from March 1995 to April 2005, with an average follow-up period of 6.2 years. None of the subjects had any history of vascular events at baseline. At follow-up, 251 incident stroke cases were identified. Using a nested, case-control study design, this analysis includes 106 cases with complete MTHFR C677T genotyping data and plasma samples. We selected 106 controls without vascular events matched for age, sex, community and years of plasma storage. Plasma total homocysteine (tHcy) level was measured by high-performance liquid chromatography. Results: Hypertension was independently associated with incident stroke and stroke death after adjusting for important covariates including plasma log-transformed Hcy level. Relative to non-carriers of the MTHFR 677TT genotype with no hypertension, the adjusted odds ratio (95% confidence interval) of stroke and stroke death among hypertensive carriers of the MTHFR 677TT genotype was 10.6 (3.2 to 34.8), 5.8 (1.6 to 21.3), respectively. After excluding subjects with plasma Hcy above 20 μmol/L, the relative odds for stroke, but not for stroke death, was more significantly pronounced (OR = 24.1, 95% CI: 2.3 to 246.1) among subjects with moderate plasma Hcy levels. However, there was no significant interactive effect between hypertensive status and the MTHFR C677T variant on the odds of the two outcomes as estimated by interaction models. Conclusions: Our major findings suggest that joint effects of the MTHFR C677T polymorphism and hypertension are consistent in predicting a significantly high risk of stroke. In addition for moderate plasma levels of Hcy, the predicted effects on the risk for the primary end point of stroke were more pronounced. These results may help to modify current approaches to vascular disease prevention in Chinese hypertensive patients.

Methylenetetrahydrofolate Reductase C677T Polymorphism and Recurrent Pregnancy Loss Risk in Asian Population: A Meta-analysis.

The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene was implicated to be associated with thrombophilia due to its role in catalyzing the formation of 5-methylenetetrahydrofolate, a co-substrate for the conversion of homocysteine to methionine. Several case-control studies were investigated MTHFR C677T polymorphism as risk for recurrent pregnancy loss (RPL). These studies rendered contradictory results, some indicating that the polymorphism is associated with the risk of RPL whereas others concluded there is no association. To shed light on these inconclusive findings, a meta-analysis of all available studies published from Asian population relating the C677T polymorphism to the risk of RPL was conducted. The following electronic databases were searched without language restrictions: PubMed, Google Scholars, Elsevier and Springer Link up to December, 2015. Meta-analysis was performed using MetaAnalyst and Mix version 1.7. Meta-analysis results suggested that MTHFR C677T polymorphism contributed to the increased RPL risk in Asian population using all five genetic models (for T vs. C: OR 1.35, 95% CI 1.09-1.68, p=0.009; for TT+CT vs. CC: OR 1.44, 95% CI 1.14-1.82, p=0.006; for CT vs. CC: OR 1.39, 95% CI 1.07-1.8, p=0.01; for TT vs. CC: OR 1.79, 95% CI 1.23.2.6, p=0.007; for TT vs. CT+CC: OR 1.61, 95% CI 1.02-2.56, p=0.04). In conclusion, this meta-analysis demonstrates a strong association between the MTHFR C677T variant and RPL in Asian population and raising the importance of the use of folate in its treatment and prevention.

Evaluating the role of maternal folic acid supplementation in modifying the effects of methylenetetrahydrofolate reductase (C677T and A1298C) gene polymorphisms in oral cleft children.

Background:We studied the role of maternal folic acid supplementation in modifying the effects of methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) gene polymorphisms in Iranian children with oral clefts.Materials and Methods:Forty-seven newborn infants with orofacial cleft and their mothers were selected randomly. Mothers were matched regarding dietary folate intake. The genotyping on venous blood was carried out. Consistency between maternal and child genotypes was analyzed.Results:Genotype consistency was not statistically significant in both C677T and A1298C gene variants (P > 0.05).Conclusion:Maternal folic acid consumption may not have any significant effect on modifying C677T and A1298C polymorphisms in children.

Association between MTHFR C677T polymorphism and diabetic nephropathy in the Chinese population: An updated meta-analysis and review.

To clarify the effects of MTHFR C677T polymorphism on the risk of diabetic nephropathy (DN) in the Chinese population, an updated meta-analysis was performed. Related studies were identified from PubMed, Springer Link, Ovid and Chinese Databases up to 24 February 2015. A total of 15 studies including 1227 DN cases, 586 healthy controls and 1277 diabetes mellitus (DM) controls were involved in this meta-analysis. Overall, a significantly elevated risk of DN was associated with all variants of MTHFR C677T when compared with the healthy group (T vs C, odds ratio (OR) = 2.22, 95% confidence interval (CI) = 1.88-2.61; TT vs CC, OR = 4.22, 95% CI = 3.02-5.90; TT + CT vs CC, OR = 2.62, 95% CI = 2.07-3.31; TT vs CC + CT, OR = 2.81, 95% CI = 2.08-3.81) or DM (T vs C, OR = 1.78, 95% CI = 1.59-2.00; TT vs CC, OR = 2.95, 95% CI = 2.33-3.73; TT + CT vs CC, OR = 1.93, 95% CI = 1.63-2.29; TT vs CC + CT, OR = 2.31, 95% CI = 1.87-2.84). In subgroup analyses stratified by ethnicity and geographic areas, it revealed the significant results in Chinese Han, in North and South China. The risk conferred by MTHFR C677T polymorphism is higher in North China than in South China. This meta-analysis showed that the MTHFR C677T variants may influence DN risk in Chinese, and further studies with gene-gene and gene-environment interactions are required for definite conclusions.

Non-syndromic cleft lip with or without cleft palate in Asian populations: Association analysis on three gene polymorphisms of the folate pathway

ObjectiveOrofacial clefts (OFCs) are one of the most common birth defects in humans. They are the subject of a number of investigations aimed at elucidating the bases of their complex mode of inheritance involving both genetic and environmental factors. Genes belonging to the folate pathway have been among the most studied. The aim of the investigation was to replicate previous studies reporting evidence of association between polymorphisms of folate related genes and the occurrence of non-syndromic cleft lip with or without cleft palate (NSCL/P), using three independent samples of different ancestry: from Tibet, Bangladesh and Iran, respectively. DesignSpecifically, the polymorphisms rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were tested. ResultsA decreased risk of NSCL/P was observed in patients presenting the C677T variant at MTHFR gene (relative risk for heterozygotes=0.53; 95% confidence interval [C.I.]=0.32–0.87). The investigated polymorphisms mapping at TCN2 and CBS genes did not provide any evidence of association. ConclusionOverall, these results indicate that NSCL/P risk factors differ among populations and confirm the importance of testing putative susceptibility variants in different genetic backgrounds.

Maternal and neonatal MTHFR-C677T mutation: A case report

Homozygosis for the thermolabile variant (C677T) of the methylene-tetrahydropholate reductase (MTHFR) gene has been related to a high incidence of neural tube defects, pre-eclampsia, retardation in fetal growth and hyperhomocysteinemia. The latter represents a known risk factor for thrombosis. We report the case of a newborn with severe cerebral damage and neonatal epilepsy that needed treatment with antiepileptic drugs. The mother was to be found homozygote for the C677T variant of the MTHFR gene and the child was to be found heterozygote for the same mutation. We underline the possible correlation between the fetal-perinatal adverse events and the mother’s genetic metabolic risks.

A potential interaction between COMT and MTHFR genetic variants in Han Chinese patients with bipolar II disorder.

Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function. The current study examined the association and interaction of the COMT Val158Met and MTHFR C677T variants with BP-II. Nine hundred seventy-eight participants were recruited: 531 with BP-II and 447 healthy controls. The genotypes of the COMT and MTHFR polymorphisms were determined using a polymerase chain reaction-restriction fragment length polymorphism analysis. Logistic regression analysis showed a significant interaction effect of the COMT Val158Met Val/Val genotype and the MTHFR C677T C/T + T/T genotype (P = 0.039) for the protective effect on the odds of developing BP-II. Our findings support preliminary evidence that the COMT and MTHFR genes interact in BP-II, and they imply the connection of both dopaminergic pathways and methylation pathways in the pathogenesis of BP-II.

Effects of dietary folate intake on migraine disability and frequency.

Migraine is a highly disabling disease affecting a significant proportion of the Australian population. The methylenetetrahydrofolate reductase (MTHFR) C677T variant has been associated with increased levels of homocysteine and risk of migraine with aura (MA). Folic acid (FA), vitamin B6 , and B12 supplementation has been previously shown to reduce increased levels of homocysteine and decrease migraine symptoms. However, the influence of dietary folate intake on migraine has been unclear. The aim of the current study was to analyze the association of dietary folate intake in the form of dietary folate equivalent, FA, and total food folate (TFF) on migraine frequency, severity, and disability. A cohort of 141 adult females of Caucasian descent with MA was genotyped for the MTHFR C677T variant using restriction enzyme digestion. Dietary folate information was collected from all participants and analyzed using the "FoodWorks" 2009 package. Folate consumption was compared with migraine frequency, severity, and disability using linear regression. A significant inverse relation was observed between dietary folate equivalent (R(2) = 0.201, B = -0.002, P = .045, 95% confidence interval [CI] [-0.004, -0.001]) and FA (R(2) = 0.255, B = -0.005, P = .036, 95% CI [-0.009, -0.002]) consumption and migraine frequency. It was also observed that in individuals with the CC genotype for the MTHFR C677T variant, migraine frequency was significantly linked to FA consumption (R(2) = 0.106, B = -0.004, P = .029, 95% CI [-0.007, -0.004]). The results from this study indicate that folate intake in the form of FA may influence migraine frequency in female MA sufferers.

Folate Metabolism and Genetic Variant in Down Syndrome: A Meta-Analysis

Objectives: Studies investigating the association between gene polymorphisms involved in homocysteine/folate metabolism and Down syndrome (DS) have reported contradictory or inconclusive results. A meta- analysis of 25 studies on association between MTHFR and MTRR polymorphism and DS including 1, 934/2,081/ cases/controls for MTHFR C677T polymorphism, 1,404/1,632/ cases/control for MTHFR A1298C polymorphism and 859 /1,132/cases/ control for MTRR A66G polymorphism was carried out. Study design: Studies were identified by searching the PubMed database for relevant articles published. Case – control studies were chosen, and odds ratio (OR) with confidence interval (CI) were used to assess the strength of association. Results: The overall results suggested that the variant genotypes MTHFR C677T were associated with DS risk (homozygote, TT vs. CC: OR=2.991; 95% CI: 1.321-3.558; P=0.001 and co dominant model, CT vs. CC: OR=1.1616 (1.216-1.845; P=0.0001). The result of the variant genotypes MTHFR A1298C showed its association with the DS risk (homozygote, AA vs. CC: OR=1.428; 95% CI: 1.016-1.849; P=0.0067).In the stratified analysis, results obtained in variant genotype of MTHFR C677T A66G had increased risk of DS in Caucasian subjects in codominant and dominant model while the increased risk was found in dominant models for Brazilian and Asian subjects. Again, for MTHFR A1298C variant, increased risk was found in Caucasian subject in co-dominant, dominant and recessive models and in co-dominant model for Brazilian population. The results also show that in A66G variant of MTRR had increased risk of DS in both Caucasian and Brazilian subjects in dominant model. Conclusion: This meta-analysis supports the idea that MTHFR C677T and MTHFR A1298C genotype is associated with increased risk for DS.

Effect of MTHFR Polymorphisms on Gastrointestinal Cancer Risk in Italy.

BackgroundThe aim of the study was to assess the association of single nucleotide polymorphisms (SNPs) C677T and A1298C in the methylenetetrahydrofolate reductase gene with colorectal, esophageal/gastric and pancreatic cancer in a cohort of Italian patients.MethodsA total of 790 cancer patients and 202 healthy controls were genotyped and distributions in genotype and allele frequencies were compared by Chi-squared analysis and logistic regression analysis.ResultsAccording to most of previous findings, we found an effect of the C677T variant, but no effect of the A1298C, in colorectal and esophageal/gastric, whereas no association was evidenced with pancreatic cancer. We found that only homozygous TT carriers of the C677T variant had an increased risk for onset of cancer.ConclusionThis result could be related to dietary and behavioral habits of the analyzed population, which could mitigate the deleterious effect of the T allele in heterozygosity and it highlights the importance to validate genetic determinant of cancer risk in different population and geographical areas.

Interaction between COMT and MTHFR genetic variants protect against risk for bipolar II disorder in Han Chinese

Objectives: Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenete trahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function. The current study examined the association and interaction of the COMT Val158Met and MTHFR C677T variants with BP-II.

Association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with ischemic stroke in the Eastern Chinese Han population.

The association between the MTHFR genetic polymorphism and ischemic stroke has been reported by a number of investigators. However, the results have been controversial and conflicting. The aim of this study was to explore the association between the MTHFR variants C677T and A1298C and the risk of ischemic stroke in an Eastern Chinese Han population. A total of 199 patients with ischemic stroke and 241 controls were recruited. Genotyping of the MTHFR C677T and A1298C polymorphisms was carried out using the Taqman 7900HT Sequence Detection System. The overall estimates (odds ratio: OR) for the allele (C) and genotype (AC+CC) of the A1298C polymorphism were 1.57 [95% confidence interval (CI) = 1.16-2.10], and 2.36 (95%CI = 1.39-4.00), respectively, establishing significant association of the MTHFR A1298C polymorphism with ischemic stroke. In contrast, there were no statistically significant differences compared to controls between MTHFR C677T polymorphic variants in the association ischemic stroke risk. Furthermore, haplotype-based analysis demonstrated that compared with the C-677-A-1298 haplotype, the C-677-C-1298 and T-677-C-1298 haplotypes showed significant increased risk of ischemic stroke (OR = 1.56; 95%CI = 1.07- 2.2; P = 0.02; OR = 1.76; 95%CI = 1.17-2.65; P < 0.01, respectively). We concluded that the A1298C polymorphism and the haplotypes C-677-C-1298 and T-677-C-1298 in MTHFR might modulate the risk of ischemic stroke in the Eastern Chinese Han population.

Distribution and determinants of plasma homocysteine levels in rural Chinese twins across the lifespan.

Plasma homocysteine (Hcy) is a modifiable, independent risk factor for cardiovascular disease (CVD) and is affected by both environmental and genetic factors. This study aimed to describe the gender- and age-specific distribution of Hcy concentration for 1117 subjects aged 10–66 years, a subset of a community-based rural Chinese twin cohort. In addition, we examined environmental and genetic contributions to variances in Hcy concentration by gender and age groups. We found that the distribution pattern for Hcy varied by both age and gender. Males had higher Hcy than females across all ages. Elevated Hcy was found in 43% of male adults and 13% of female adults. Moreover, nearly one fifth of children had elevated Hcy. Genetic factors could explain 52%, 36% and 69% of the variation in Hcy concentration among children, male adults and female adults, respectively. The MTHFR C677T variant was significantly associated with Hcy concentrations. Smokers with the TT genotype had the highest Hcy levels. Overall, our results indicate that elevated Hcy is prevalent in the children and adults in this rural Chinese population. The early identification of elevated Hcy will offer a window of opportunity for the primary prevention of CVD and metabolic syndrome.

Associations of MTHFR C677T and MTRR A66G gene polymorphisms with metabolic syndrome: a case-control study in Northern China.

Prior evidence indicates that homocysteine plays a role in the development of metabolic syndrome (MetS). Methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms are common genetic determinants of homocysteine levels. To investigate the associations of the MTHFR C677T and MTRR A66G polymorphisms with MetS, 692 Chinese Han subjects with MetS and 878 controls were recruited. The component traits of MetS and the MTHFR C677T and MTRR A66G genotypes were determined. A significant association was observed between the MTHFR 677T allele and increased risk of MetS, high fasting blood glucose, high waist circumference, and increasing number of MetS components. The MTRR A66G polymorphism was associated with an increased risk of MetS when combined with the MTHFR 677TT genotype, although there was no association found between MetS and MTRR A66G alone. Furthermore, the MTRR 66GG genotype was associated with high fasting blood glucose and triglycerides. Our data suggest that the MTHFR 677T allele may contribute to an increased risk of MetS in the northern Chinese Han population. The MTRR A66G polymorphism is not associated with MetS. However, it may exacerbate the effect of the MTHFR C677T variant alone. Further large prospective population-based studies are required to confirm our findings.

Association of MTHFR genetic variants C677T and A1298C on predisposition to spontaneous abortion in Slavonic population

AimUp to 20% of pregnancies end in the first trimester by spontaneous abortion but the cause of a large proportion remains unexplained. The aim of this study was to investigate the role of two common variants (rs1801133, C677T and rs1801131, A1298C) within the MTHFR gene in the genetic determination of spontaneous abortions. MethodsDNA from 464 tissue samples of spontaneous abortions and population sample of adults (N=2,486) were genotyped for both MTHFR polymorphisms of interest. ResultsThe frequencies of the MTHFR polymorphisms in tissues from spontaneous abortions did not differ from the population cohort. However, when combined, carriers of at least three rs1801133 and/or rs1801131 alleles were more common in the spontaneous abortions (61.4%) than in controls (55.4%) and this combination was associated with higher risk of abortion (OR 1.28; 95% CI 1.05–1.57; P=0.017). In contrast, carriers of at least three minor alleles (T677 and C1298) of these polymorphisms were very rare in both groups (0.8% and 0.9% respectively). ConclusionsOur study suggests that distinct combinations of the MTHFR polymorphisms could be associated with higher risk of spontaneous abortions in Caucasians.

Mitochondrial dysfunction by pro-oxidant vanadium: Ex vivo assessment of individual susceptibility

The aim was to assess the individual susceptibility to mitochondrial impairment induced by ex vivo exposure to vanadium, an airborne pro-oxidant pollutant. In lymphocyte cultures V(IV)-treated of forty-five healthy subjects, we evaluated the mitochondrial transmembrane potential (Δψm) and the H2O2 in comparison to background values.As variables, we included both lifestyle factors and genetic polymorphisms (GSTM1 and GSTT1 variants, and C677T and A1298C variants of methylenetetrahydrofolate reductase MTHFR).H2O2 mitochondrial content increased significantly (P<0.05) after metal exposure while, in comparison to basal Δψm, both depolarisation and hyperpolarisation were recorded. This underlined the mitochondrial dysfunction vanadium-induced that worsens the redox imbalance by endogenous ROS overproduction.Only age was found to contribute significantly to the high inter-individual variability, as assessed by multivariate analysis. In older subjects, the H2O2/Δψm values underline the organelle impairment and, under V-exposure, Δψm values were inversely related to age (R=−0.591; P=0.012).

The effect of IL-4 and MTHFR gene variants in ankylosing spondylitis.

Ankylosing Spondylitis (AS) is a chronic inflammatory rheumatic disease that characteristically affects the sacroiliac joints and the spine. The exact pathogenesis of AS remains poorly understood, but genetic factors play a key role in disease development. Several genes have been consistently associated with susceptibility to AS. This study was conducted in Turkish AS patients to determine the frequency of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and interleukin-4 (IL-4) gene 70bp variable number of tandem repeats (VNTR) variants, as well as their association with clinical characteristics. Genomic DNA obtained from 272persons (122AS patients and150healthy controls) was used in this study. Genomic DNA was isolated and genotyped using a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay for the MTHFR C677T and IL-4 70bp VNTR gene variants, which were determined using specific PCR primers. There was statistically significant difference between the groups with respect to MTHFR genotype distribution (p = 0.02) and allele frequencies (p < 0.001). When we examined MTHFR and IL-4 genotype frequencies according to clinical characteristics, we found an association between the homozygous MTHFR TT genotype and ocular involvement, although this did not reach statistical significance (p = 0.02). However, we did not find any difference between the groups with respect to IL-4 genotype distribution or allele frequencies and clinical characteristics (p > 0.05). Our findings suggest that there is an association of the MTHFR gene C677T polymorphism with the susceptibility of a person for development of AS. However, the IL-4 gene is not associated with AS within the same population.