IN RESPONSE to many requests from individuals and agencies, the following statement on the present status of treatment of phenylketonuria (PKU) has been prepared. The Committee on Fetus and Newborn has reviewed the present status of neonatal screening for inborn errors of metabolism (e.g., PKU and related problems) and is reporting separately.
There is considerable discrepancy of opinion regarding the treatment of phenylketonuria. The enthusiasts say that with adequate mass screening, diagnosis, and early treatment, phenylketonuria can be eliminated as a cause of mental retardation; the doubters believe that there is need to improve screening procedures and that the efficacy of treatment leaves much to be desired.
AREAS OF AGREEMENT ON TREATMENT
In spite of discrepancies in the available data, certain facts appear to warrant acceptance, namely:
1. If PKU is detected early, and the infant is started on the proper diet before 6 months of age, and then is "adequately" maintained, the child usually will demonstrate borderline to average intelligence at 5 years of age. The earlier treatment is begun, in general, the better the result.
2. For the infant being treated with a diet low in phenylalanine, the acceptable concentration of phenylalanine in the serum probably lies above 3 mg/100 ml and below 8 mg/100 ml. Some insist that it be kept below 4-6 mg/100 ml. Concentrations over 12 mg/100 ml are almost certainly too high to achieve best results.
3. For optimum results the diet must be maintained rigidly and constantly, and at the same time the parents must also offer the child the usual affection, stimulation, discipline, and security necessary for normal behavioral development.
Treatable inborn errors of metabolism causing intellectual disability: A systematic literature review