Figure 1. MTHFR polymorphism was analyzed by PCR-RFLP. (A) The polymorphism at position 677 was analyzed by PCR followed by HinfI restriction enzyme digestion. Lane 1, marker 50 bp; lanes 2 and 4, wild-type homozygotes; lane 3, mutant homozygotes; lane 5, mutant heterozygotes. (B) The polymorphism at position 1298 was examined by PCR followed by MboII restriction enzyme digestion. Lane 1, marker 25 bp; lane 2, wild-type homozygotes; lane 3, mutant homozygotes; lane 4, mutant heterozygotes. PCR-RFLP, polymerase chain reaction with restriction fragment length polymorphism.