Variations in folate pathway genes are associated with unexplained female infertility.

Objective: To investigate associations between folate-metabolizing gene variations, folate status, and unexplained female infertility.
Design: An association study.
Setting: Hospital-based IVF unit and university-affiliated reproductive research laboratories.
Patient(s): Seventy-one female patients with unexplained infertility.
Intervention(s): Blood samples for polymorphism genotyping and homocysteine, vitamin B12, and folate measurements.
Main Outcome Measure(s): Allele and genotype frequencies of the following polymorphisms: 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C/T, 1298A/C, and 1793G/A, folate receptor 1 (FOLR1) 1314G/A, 1816delC, 1841G/A, and 1928C/T, transcobalamin II (TCN2) 776C/G, cystathionase (CTH) 1208G/T and solute carrier family 19, member 1 (SLC19A1) 80G/A, and concentrations of plasma homocysteine, vitamin B12, and serum folate.
Result(s): MTHFR genotypes 677CT and 1793GA, as well as 1793 allele A were significantly more frequent among controls than in patients. The common MTHFR wild-type haplotype (677, 1298, 1793) CAG was less prevalent, whereas the rare haplotype CCA was more frequent in the general population than among infertility patients. The frequency of SLC19A1 80G/A genotypes differed significantly between controls and patients and the A allele was more common in the general population than in infertile women. Plasma homocysteine concentrations were influenced by CTH 1208G/T polymorphism among infertile women.
Conclusion(s): Polymorphisms in folate pathway genes could be one reason for fertility complications in some women with unexplained infertility.
(Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)