Objective: To study the influence of mutation of 677 C to T in the methylenetetrahydrofolate reductase (MTHFR) gene on the plasma total homocysteine (tHcy) levels in hemodialysis patients.
Methods: The study population included 40 healthy subjects and 53 patients with end-stage renal disease (ESRD) undergoing hemodialysis. C 677 T transition in the MTHFR gene was detected by Hinf 1 restriction enzyme analysis. Plasma tHcy concentrations were determined by HPLC with fluorescent detection. Serum folate and vitamin B(12) levels were measured with chemiluminescent immunoassay.
Results: The allelic frequency of the 677 C to T transition in the MTHFR gene in hemodialysis patients was 52.8% versus 53.8% in healthy controls. The mean tHcy level was significantly higher in hemodialysis patients than that in control subjects (38.68 micro mol/L versus 15.47 micro mol/L, P < 0.01). The folate and vitamin B(12) concentrations were higher in patients than those in controls. There was a significant influence of the +/+ genotype, folate and vitamin B(12) status on plasma tHcy level.
Conclusion: It is demonstrated that the extent of hyperhomocysteinemia in hemodialysis patients is not only the result of impaired metabolism and elimination of Hcy in uremia, but is also genetically determined by the MTHFR genotype. Folate and vitamin B(12) status also influences the homocysteine concentration of hemodialysis patients.