title: Effect of glutamate carboxypeptidase II and reduced folate carrier polymorphisms on folate and total homocysteine concentrations in dialysis patients.
abstract: This study was designed to examine the effect of two single nucleotide polymorphisms in the reduced folate carrier 1 (RFC1 80G>A) and the glutamate carboxypeptidase 2 (GCP2 1561C>T) gene on total homocysteine (tHcy) plasma level and folate status in 120 chronic dialysis patients. Red blood cell folate concentration was higher in patients with the GCP2 CT or TT genotype (ANOVA, P = 0.04). Among patient groups with different RFC1 genotypes, red blood cell folate level was not significantly different. A multivariate analysis confirmed that the GCP2 1561C>T genotype (P = 0.011) had a significant influence on the red blood cell folate concentration. Overall, serum folate, creatinine, and the GCP2 polymorphism explained nearly 50% of the variance of red blood cell folate. A linear multivariate regression analysis showed that red blood cell folate (P < 0.001), creatinine (P < 0.001), and the 5,10-methylenetetrahydrofolate reductase (MTHFR) 677T allele (P = 0.013) are independent predictors of tHcy plasma level explaining 49% of the variance of tHcy plasma concentration. GCP2 1561C>T and RFC1 80G>A showed no effect on tHcy and folate plasma level. In conclusion, GCP2 1561C>T, but not RFC1 80G>A, is a predictor of red blood cell folate level in chronic dialysis patients. Both polymorphisms have no major effect on tHcy plasma concentration in end-stage renal disease patients.
authors.affiliation: Institute of Medical and Chemical Laboratory Diagnostics, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: Manuela
authors.initials: M
authors.lastname: Födinger
authors.forename: Jutta
authors.initials: J
authors.lastname: Dierkes
authors.forename: Sonja
authors.initials: S
authors.lastname: Skoupy
authors.forename: Claudia
authors.initials: C
authors.lastname: Röhrer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hagen
authors.forename: Heidi
authors.initials: H
authors.lastname: Puttinger
authors.forename: Anna-Christine
authors.initials: AC
authors.lastname: Hauser
authors.forename: Andreas
authors.initials: A
authors.lastname: Vychytil
authors.forename: Gere
authors.initials: G
authors.lastname: Sunder-Plassmann
mesh_terms: D000328:Adult; D000368:Aged; D000954:Antigens, Surface; D002268:Carboxypeptidases / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000097:blood*; D005838:Genotype; D043425:Glutamate Carboxypeptidase II; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000235:genetics* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011237:Predictive Value of Tests; D011956:Receptors, Cell Surface; D006435:Renal Dialysis
chemical_list: D000954:Antigens, Surface; D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface; D006710:Homocysteine; D005492:Folic Acid; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II