Phenylalanine hydroxylase deficiency

Phenylalanine hydroxylase (PAH) deficiency is an inherited disease of variable severity. When untreated, the most severe form of PAH, called phenylketonuria (PKU), is characterized by microcephaly, epilepsy, severe intellectual and developmental disabilities, and behavioral problems. It involves defects in the enzyme phenylalanine hydroxylase, which is responsible for the breakdown of phenylalanine, one of the essential amino acids that is found in a variety of foods, including proteins and some artificial sweeteners. Major symptoms associated with PAH are due to the build-up of phenylalanine to toxic levels in the body, particularly affecting the brain. View testing options