A Case-Control Study Investigating the Effect of MTHFR C677T Variant on Performance of Elite Athletes

Objective: Increased level of plasma homocysteine (Hcy) is a potential risk factor for several multi-system diseases. The Methylenetetrahydrofolate reductase (MTHFR) gene C677T variant has been established as an important genetic determinant of hyperhomocysteinemia. There are conflicting reports about the effects of physical activity on plasma Hcy. Therefore, the main aim of this study was to investigate whether the MTHFR C677T variant affects elite athletic performance. Methods: This study was carried out on 214 individuals (114 elite athletes and 100 sedentary controls). Genotyping was performed using PCR- RFLP method. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. Results: There was a significant difference between the athletes and the control group in genotype distribution and allele frequency of the MTHFR C677T variant. MTHFR C677T CC genotype and C allele were more prevalent in elite athletes than those in the sedentary controls (p =0.007, OR: 2.16, 95%:1.26-3.70; p=0.009, OR: 1.84, 95%:1.18-2.89, respectively). The control group had a higher MTHFR C677T CT genotype than the athletes (p=0.019, OR: 0.51, 95%:0.30-0.88). There was no deviation from HWE for the MTHFR C677T variant in the groups. Conclusion: Our findings support that there is an association between the MTHFR C677T C allele and athletic performance among the elite Turkish athletes. </jats:sec

Impact of Endothelial NOS VNTR Variant on Susceptibility to Diabetic Neuropathy and Type 2 Diabetes Mellitus

Purpose:: The aim of this study was to evaluate whether the VNTR intron 4b/4a variant in the eNOS gene is associated with type 2 diabetes mellitus (T2DM) and DPN. Methods:: A total of 598 subjects were enrolled in the study. eNOS VNTR 4b/4a variant was genotyped by polymerase chain reaction (PCR) method. Results:: eNOS VNTR intron 4b/4b genotype and b allele increased in patients with both DPN and T2DM compared healthy controls (p=0.0005, OR:1.94, p= 0.000002, OR:4.10, respectively). 4a/4b genotype was more prevalent in controls than in DPN and T2DM patients (p=0.00008, OR:0.46; p=0.000004, OR:0.24, respectively). eNOS VNTR b allele was more common in DPN patients and T2DM patients compared with controls (p=0.007, p=0.00002, respectively). Conclusion:: The eNOS VNTR “4b/4b” homozygous genotype and hence “4b”allele as a genetic risk factor for T2DM and DPN, which may serve as a useful marker of increased susceptibility to the risk of these disorders. </jats:sec