Vitamin B6 and mental deficiency. The effects of large doses of B6 (pyridoxine) in phenylketonuria.

Vitamin B6 was given to 10 phenylketonuric patients in doses up to 150 mg/day for a period of 9 weeks. Their clinical signs, behavior, intelligence, E.E.G.('s), serum phenylalanine levels, urinary phenylpyruvic acid and phenol levels, and excretions of ethyl-acetate-soluble aromatic derivatives were followed serially. No changes of significance to phenylketonuria were found, although chromatographic evidence indicated some changes in excretion of a few aromatic derivatives, notably Nα-acetyltryptophan.