Effects of the glutamate carboxypeptidase II (GCP2 1561C>T) and reduced folate carrier (RFC1 80G>A) allelic variants on folate and total homocysteine levels in kidney transplant patients.
BACKGROUND
The effect of the glutamate carboxypeptidase II GCP2 1561C>T and the reduced folate carrier 1 RFC1 80G>A polymorphisms on folate and total homocysteine (tHcy) plasma levels of kidney transplant patients are unknown.


METHODS
In a cross-sectional study of 730 kidney allograft recipients, GCP2 1561C>T, RFC1 80G>A, folate, and tHcy plasma levels were analyzed using linear regression models that allowed dependent covariates to follow a gamma distribution for univariate and multivariate analyses.


RESULTS
The allele frequency for GCP2 1561C>T was 0.05, and 0.43 for RFC1 80G>A. Heterozygosity or homozygosity for GCP2 1561C>T was associated with higher folate plasma levels compared to patients without mutation (P < 0.0001), while RFC1 80G>A showed no influence. Multiple testing, also including MTHFR 677C>T and MTHFR 1298A>C, revealed no interaction between the different genotypes and the folate plasma concentration. Neither GCP2 1561C>T nor RFC1 80G>A showed an association with tHcy plasma levels.


CONCLUSIONS
We conclude that GCP2 1561C>T is associated with elevated folate levels. GCP2 1561C>T and RFC1 80G>A are no major determinants of tHcy plasma levels in kidney transplant patients.
Winkelmayer
Wolfgang C
WC
Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Eberle
Corinna
C
Sunder-Plassmann
Gere
G
Födinger
Manuela
M
D000328:Adult; D000483:Alleles; D000954:Antigens, Surface / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005838:Genotype; D043425:Glutamate Carboxypeptidase II / Q000235:genetics*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D008875:Middle Aged; D011110:Polymorphism, Genetic
D000954:Antigens, Surface; D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C120043:SLC19A2 protein, human; D006710:Homocysteine; D005492:Folic Acid; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II