Tyrosine supplementation for phenylketonuria

Randomised controlled trial of tyrosine supplementation on neuropsychological performance in phenylketonuria.

OBJECTIVE To test the efficacy of tyrosine supplementation, as an adjunct to dietary treatment, on neuropsychological test performance in individuals with phenylketonuria. DESIGN A randomised controlled trial of tyrosine supplementation using a double blind crossover procedure with three four week phases. SETTING The Hospital for Sick Children, Toronto. PARTICIPANTS 21 individuals with ph...

Phenylketonuria.

Phenylketonuria is the most prevalent disorder caused by an inborn error in aminoacid metabolism. It results from mutations in the phenylalanine hydroxylase gene. Phenotypes can vary from a very mild increase in blood phenylalanine concentrations to a severe classic phenotype with pronounced hyperphenylalaninaemia, which, if untreated, results in profound and irreversible mental disability. Neo...

Screening for Phenylketonuria

Newborn screening for phenylketonuria (PKU) started with Robert Guthrie (1916–1995) who developed the bacterial inhibition test for the semiquantitative analysis of phenylalanine, which was the first test suitable for high throughput analysis. In addition, he introduced the ‘Guthrie filter card’ as a transport medium for dried blood which is still used today. Realizing the potential of his appr...

Neonatal screening for phenylketonuria.

The case histories are reported of three patients with phenylketonuria (PKU) in whom the initial Guthrie screening for PKU was falsely negative. Possible explanations for this problem are reviewed, as well as the limited cost-effectiveness of general re-testing. Guidelines are suggested to im­ prove the sensitivity of PKU screening procedures for newborns.

Phenylketonuria