Methylenetetrahydrofolate Reductase Polymorphism in the Etiology of Down Syndrome

A methylenetetrahydrofolate reductase polymorphism (677 C/T mutation) was recently implicated in the etiology of Down syndrome. We studied a cohort of 85 women carrying fetuses with Down syndrome and found no difference in the frequencies of the three groups of subjects (C/C, C/T, T/T) between Down syndrome mothers and controls.