Phenylketonuria is an inborn error of metabolism where phenylalanine hydroxylase is deficient. Thus there is an inability to convert phenylalanine into tyrosine which results in the accumulation of phenylalanine and its metabolic products in body fluids.
The condition results in irreversible mental disability if left untreated. Other possible features of this condition include neurologic manifestations, light pigmentation and mousy odour.
The disease is inherited as an autosomal recessive disorder of chromosome 12 and has an incidence of approximately 1 per 10,000 births in the UK.
Carrier detection and prenatal diagnosis is possible using DNA analysis.
Last reviewed 03/2021