Xxxviii. Metabolic Studies in Phenylketonuria

F6LLING [1934] discovered that, in certain cases of mental deficiency, phenylpyruvic acid was excreted in the urine. His attention was drawn to the phenomenon by the characteristic colour produced by the addition of ferric chloride solution to the urines of these patients, and he identified the responsible substance as phenylpyruvic acid. Other cases have since been recognized [Penrose, 1935]. The condition is familial: more than one child in a family may be affected but the parents and remaining members of the family are usually normal. Genetically the abnormality appears to be inherited as a single Mendelian recessive character and, in this way, it resembles two other metabolic abnormalities, alcaptonuria and albinism, though it is not so rare as they are. It is proposed to refer to the condition as phenylketonuria.