Phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive human genetic disorder caused by a deficiency of hepatic phenylalanine hydroxylase enzyme activity, which prevents hydroxylation of phenylalanine into tyrosine.

PKU is a common inborn error of amino acid metabolism in Caucasian populations and approximately 1 in 50 are carriers of a PKU allele. The genetic disorder causes impairment of postnatal brain development, resulting in severe mental retardation in untreated children.

Phenylalanine is an essential amino acid provided by food that has a key role in the production of other amino acids. It is converted to tyrosine, used in the production of neurotransmitters.