An infant with seizures, spasticity, and failure in weight gain was shown to excrete p-hydroxyphenylpyruvic acid, p-hydroxyphenyllactic acid, and p-hydroxyphenylacetic acid, indicating the likelihood of an impairment in the oxidation of p-hydroxyphenylpyruvate. Institution of a phenylalanine-free diet coincided with marked clinical improvement and disappearance of the abnormal urinary metabolites. The cause of the temporary enzyme defect is discussed, and it is concluded that it represents a persistence into extrauterine life of the relative enzyme inactivity observed in fetal tissues.
Antipsychotic-Induced Weight Gain and Clinical Improvement: A Psychiatric Paradox