Abstract
The levels of the organic acids of phenylalanine: phenylacetate, phenylpyruvate and phenyllactate, and the biogenic amine, phenylethylamine (PEA) are increased in untreated phenylketonurics. There is no data regarding these neurotoxic substances in treated patients with phenylketonuria (PKU). Nineteen children with PKU, ages 2-10 years were examined for these metabolites. All children were on treatment with blood phenylalanine levels ranging from 2.4-22.2mg/dl. Phenylalanine metabolites were assayed in freshly collected urine samples. The organic acids of phenylalanine were determined by gas chromatography/mass spectrometry and PEA was determined following precolumn derivitization with dansyl chloride and isolation by high performance liquid chromatography. Phenylalanine metabolites were detected in some patients with blood phenylalanine levels below 6mg/dl. When blood levels of phenylalanine were 12-22.2mg/dl the mean excretion of phenylacetate was 237.9, phenylpyruvate was 829.7, and phenyllactate 2294.2mg/gm creatinine. These compounds are usually not detected in normal urine. Levels of PEA were 2.6 - 53.8ng/mg creatinine (normal 0.06-0.13). The increased levels of phenylalanine metabolites in PKU patients is of concern with regards to acceptable levels of blood phenylalanine in the treatment of PKU. Since loss of academic achievement in treated PKU children has been noted, lowering the levels of these metabolites may be of importance in the follow-up of children with PKU.
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Michals, K., Matalon, R. 1237 PHENYLALANINE METABOLITES IN TREATED PHENYLKETONURIC CHILDREN. Pediatr Res 19, 317 (1985). https://doi.org/10.1203/00006450-198504000-01267
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DOI: https://doi.org/10.1203/00006450-198504000-01267