Hyperphenylalaninaemia

Abstract

Mutations within the gene for the hepatic enzyme phenylalanine hydroxylase (PAH) and those involving enzymes of pterin metabolism are associated with hyperphenylalaninaemia (HPA). Phenylketonuria (PKU) is caused by a severe deficiency in PAH activity and if left untreated leads to permanent central nervous system damage. Dietary restriction of phenylalanine (PHE) along with amino acid, vitamin and mineral supplements, started in the first weeks of life and continued through childhood, is an effective treatment and allows for normal cognitive development.