ASD probands showed a higher frequency of rs2298444 'A' allele (P = 0.01) and genotypes with 'A' allele (P = 0.03) when compared with the controls. rs1801198 'C' allele and 'CG' genotype also showed higher occurrence in the probands (P = 0.009 and 0.005, respectively).
MATERIAL AND METHODS Genotypes of transcobalamin 2 (TCN2) rs1801198, methionine synthase (MTR) rs1805087, methionine synthase reductase (MTRR) rs1801394, and methylene tetrahydrofolate reductase (MTHFR) rs1801133 were examined in 201 children with ASD and 200 healthy controls from the Han Chinese population.