Phenylketonuria Treated from Earliest Infancy
This paper reports the development of three patients (ages 3
years, 2 4/12 years and 1 year) who received a phenylalanine-deficient diet from early infancy as treatment for phenylketonuria. Each one of the cases had one or more severely retarded siblings with phenylketonuria. Because of this background, the detection of phenylketonuria was possible early in infancy, between a few days and 7 weeks of life. Immediately upon diagnosis a phenylalanine-free diet was instituted; after the initial diet had been administered for 3 weeks, 2 gm of natural protein in the form of cow's-milk was added to the diet. At about 6 months of age the natural protein was increased to 3 gm a day. The concentration of phenylalanine in the serum was maintained between 3 and 7 mg/100 ml. The mental and physical development of these patients progressed normally throughout the period of observation. As each of the patients had the diagnosis of phenylketonuria established by detection of abnormal phenylketonuria and elevated concentrations of phenylalanine in the plasma, it seems reasonable to conclude that the development of these patients in a normal fashion is a reflection of the treatment, although some untreated cases may have normal or near normal intelligence.
