aetiology
Last reviewed 09/2021
The disease is the result of an autosomally recessive inheritance of a lack of hepatic phenylalanine hydroxylase. The normal conversion of phenylalanine to tyrosine does not occur in children born with phenylketonuria. The abnormally high amounts of phenylalanine and its metabolites are particularly toxic to the developing nervous system.
Another cause of phenylketonuria is a deficiency of the tetrabiopterin cofactor.