title: Children with inborn errors of phenylalanine metabolism: prognosis and phenylalanine tolerance.
abstract: Twenty-three children, who were detected by neonatal PKU screening, were followed for 8-18 years in one paediatric centre. Dietary treatment was started if the blood phenylalanine level exceeded 0.72 mmol/l. All 23 infants were initially given a low phenylalanine diet. The growth and development rates of the children did not differ significantly from those in a reference population, although one child had mild mental retardation and another had a short attention span. Fourteen children were still on a strict phenylalanine-restricted diet on their last follow-up (at 8-18 years of age). In nine children who were initially put on a low phenylalanine diet, it was possible to normalize the diet between 1/2 and 10 years of age, while maintaining the blood phenylalanine levels between 0.25 and 0.72 mmol/l. It seems likely that those of our patients who markedly increased their phenylalanine tolerance during childhood had a regulatory mutation of the phenylalanine hydroxylase system. A continuous reevaluation of each child treated with a low phenylalanine diet reduces the use of unnecessarily restricted diets.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000209:etiology; D008297:Male; D008403:Mass Screening; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias / Q000097:blood* / Q000178:diet therapy / Q000453:epidemiology; D011379:Prognosis; D013548:Sweden
chemical_list: D010649:Phenylalanine