EXPERIMENTAL PHENYLKETONURIA IN INFANT MONKEYS.

Experimental phenylketonuria can be produced in infant monkeys by feeding excessive quantities of L-phenylalanine soon after birth. Both the phenylketonuric monkey and the phenylketonuric human patient have elevated plasma levels of phenylalanine, and monkey and human excrete almost the same phenylalanine metabolites in the urine. Grand-mal convulsions, observed in some children with phenylketonuria, were also observed in the experimental animals. The biochemical evidence was supported by the learning data. The observed slowness in adapting to testing procedures, or even failure to adapt, and the inadequate performance suggest an intellectual deficit.