Phenylketonuria (PKU)

Phenylketonuria is an autosomal recessivedisease (8-10 cases / 100,000 individuals) due to absence or  phenylalanine hydroxylase activity  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), phenyllactate, phenylacetate or phenylethylamine is formed. These substances accumulate in tissues and body fluids and cause a typical urine odor. 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 by a strict Phe-restricted diet.