With respect to spina bifida, we observed ORs with 95% confidence intervals that did not include 1.0 for the following SNPs (heterozygous or homozygous) relative to the reference genotype: BHMT (rs3733890) OR = 1.8 (1.1-3.1), CBS (rs2851391) OR = 2.0 (1.2-3.1); CBS (rs234713) OR = 2.9 (1.3-6.7); MTHFD1 (rs2236224) OR = 1.7 (1.1-2.7); MTHFD1 (hcv11462908) OR = 0.2 (0-0.9); MTHFD2 (rs702465) OR = 0.6 (0.4-0.9); MTHFD2 (rs7571842) OR = 0.6 (0.4-0.9); MTHFR (rs1801133) OR = 2.0 (1.2-3.1); MTRR (rs162036) OR = 3.0 (1.5-5.9); MTRR (rs10380) OR = 3.4 (1.6-7.1); MTRR (rs1801394) OR = 0.7 (0.5-0.9); MTRR (rs9332) OR = 2.7 (1.3-5.3); TYMS (rs2847149) OR = 2.2 (1.4-3.5); TYMS (rs1001761) OR = 2.4 (1.5-3.8); and TYMS (rs502396) OR = 2.1 (1.3-3.3).
Transmission disequilibrium of SNP alleles in cystathionine-beta-synthase, dihydrofolate reductase, methylenetetrahydrofolate reductase, and thymidylate synthetase confers an increased susceptibility to SB.
Some data suggest that the risk for spina bifida associated with C677T homozygosity may depend on nutritional status (e.g., blood folate levels, intake of vitamins) or on the genotype of other folate-related genes (e.g., cystathionine-beta-synthase and methionine synthase reductase).