sensitive radioenzymatic assay that measures directly the reductive catalysis of N ,N -methylenetetrahydrofolate. The radio-labeled substrate, [ C14]N ,N -methyl enetetrahydrofolate, is prepared by condensation of [C14]formaldehyde with tetrahydrofolate. Its stability is maintained for several months by storage at -80°C in a pH 9.5 buffer
testing of 478 individuals with myelomeningocele for attention-deficit hyperactivity disorder (ADHD) behavior plus genotyping for seven single nucleotide polymorphisms in the MTHFR gene. 28.7% of myelomeningocele participants exhibit rating scale elevations consistent with ADHD, of these 70.1% have scores consistent with the predominantly inattentive subtype. There is a positive association between the SNP rs4846049 in the 39-untranslated region of the MTHFR gene and the attention-deficit hyperactivity disorder phenotype in myelomeningocele participants