A polymorphism in methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), R653Q (MTHFD1 c.1958 G > A), has also been associated with increased birth defect risk, likely through reduced purine synthesis.
The minor allelic frequencies of the MTHFD1 1958G>A and MTHFR 1298A>C in our populations were similar to those reported from Southeast Asian population, suggesting a possible explanation for the prevalence of this malformation in these regions.
In people, a single nucleotide polymorphism of this gene (1958G>A; rs2236225) is associated with increased risk for bipolar disorder and schizophrenia, neural tube and other birth defects.