Phenylketonuria (PKU)

Phenylketonuria is an autosomal recessivedisease (8-10 cases / 100,000 individuals) due to the absence or phenylalanine hydroxylase activity. It physiologically catalyzes the hydroxylation of Phe to Tyr. In the case of an enzyme defect, there is an alternative degradation of Phe - phenylpyruvate (transamination), phenylacetate, phenylacetate or phenylethylamine is formed. These substances accumulate in tissues and body fluids and cause a typical urine odour. Some of them cause severe brain damage.

Phenylketonuria was the first human genetic defect in amino acid metabolism to be discovered and is currently one of the diseases screened in all newborns. If we can recognize it at this age, we can prevent brain damage with a strict Phe-restricted diet.

 For more information see Phenylketonuria.

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