Influence of 5,10-methylenetetrahydrofolate reductase gene polymorphism onplasma homocysteine concentration in patients with end-stage renal disease

The purpose of this study is to observe the influence of the methylenetetra hydrofolate reductase (MTHFR) gene (677C-->T substitution) on plasma homocy steine levels in end-stage renal disease (ESRD) patients who received a rel atively large amount of folate (2 mg/d) and are undergoing hemodialysis. A cross-sectional study of plasma homocysteine, vitamin B-12, and folate was performed in patients with ESRD. The study population for the MTHFR gene st udy included 312 healthy subjects and 106 patients with ESRD undergoing hem odialysis. The C677T transition in the MTHFR gene was detected by HinF 1 re striction enzyme analysis and subsequent electrophoresis in a 3% agarose ge t, The genotype of the MTHFR gene in 106 patients with ESRD was homozygous C677T mutation (VV) in 17 patients (16.1%) and heterozygous (AV) in 63 pati ents (58.4%); 26 patients (24.5%) did not carry this mutation (AA), The mea n levels of homocysteine, vitamin B-12, and folate in the patients with ESR D were 23.3 +/- 14.0 mmol/L, 620.2 +/- 98.5 pmol/L, and 138.6 +/- 55.6 nmol /L, respectively. There was no significant difference in homocysteine level s among the three genotypes: 28.2 +/- 19.4 mmol/L for VV, 22.7 +/- 14.9 mmo l/L for AV, and 23.4 +/- 11.1 mmol/L for AA genotype (P > 0.05). There was no difference in genotype distribution between the patient groups of less t han 25th and greater than 75th percentiles, classified according to plasma homocysteine levels (P = 0.47), In conclusion, with high-dose folate supple mentation, the hyperhomocysteinemia in patients with ESRD does not seem to be caused by the 677C-->T mutation in the MTHFR gene. (C) 1999 by the Natio nal Kidney Foundation, Inc.