“…Stroke, mental retardation, and seizures have been studied extensively, but psychiatric impairment has received considerably less attention. For example, three patients with cystathionine P-synthase deficiency were said to have schizophrenia, but the clinical details were insufficient to confirm this diagnosis [Schimke et al, 1965;Beals, 1969;Rahman, 19721. Other patients with a variety of pyschiatric symptoms have been described, but only superficially [McKusick, 1972;Turner, 1967;Hagberg and Hambraeus, 1968;Price et al, 1968;Kaeser et al, 1969;Kang et al, 19701. Furthermore, any relationships among intelligence, biochemical characteristics, and neuropsychiatric problems have not been examined formally.…”