Purpose: To explore the relationship between genetic polymorphisms in reduced folate carrier 1 (RFC-1), cystathionine b-synthase (CBS), two key genes in folate metabolism, and the risk of Down syndrome in China.
Methods: Genomic DNA was isolated from the peripheral lymphocytes of 104 mothers born children with Down syndrome and 184 age-matched control mothers. Polymerase chain reaction and restriction-fragment length polymorphism were used to examine the polymorphisms of RFC-1 A80G, CBS T833C and the relationship between these genotypes and the risk of Down syndrome was analyzed.
Results: We found that there were significant differences between RFC-1 G80G, CBS C833C polymorphisms among mothers of children with Down syndrome than among control mothers, with odds ratio of 1.51 (95 % CI 1.05-2.18), 1.53 (95 % CI 1.07-2.18) respectively. The combined presence of RFC1 mutant alleles and the CBS homozygous mutant allele (15/104) was associated with a 4.81-fold increased risk of having a child with Down syndrome (95 % CI 1.82-12.68, P = 0.0007).
Conclusions: We concluded that RFC-1 and CBS gene mutation alleles are related to Down syndrome, and women with mutation RFC-1 G80G, CBS C833C OR combined with RFC-1 A80G and CBS 833TT genotype increase the risk of Down syndrome in China.