Familial protein intolerance with deficient transport of basic amino acids. Report on an adult patient with chronic hyperammonemia.

An adult patient suffering from protein intolerance with deficient transport of basic amino acids is described. The early history of the patient was typical of this inborn disorder of amino acid metabolism: weaning was followed by prolonged diarrhea, spontaneous restriction of protein in the diet, and by slow growth. Abandonment of the carbohydrate-fat diet at the age of 18 years was followed by an increased growth rate and, in a very few months, by mental changes. The timing of these three incidents suggests a causal relationship between them. It therefore seems that both normal body growth and normal cerebral function are possible in protein intolerance; in the individual patient, however, they seem to be mutually exclusive. Analogous considerations in other inborn metabolic disorders of urea synthesis have been presented (2, 5).