Phenylketonuria (PKU)

An autosomal recessive (from both parents) disorder in which the absence of the enzyme phenylalanine hydroxylase (PAH) causes a toxic buildup pf phenylalanine in the blood and urine.  If not treated early, this can lead to mental retardation and neurological problems.  Symptoms can include cognitive impairment, a “mousy” odor of the body and urine, light skin pigmentation, an eczema rash, asthma, hyperactivity, and neurological problems.  Newborn screening programs often test for PKU.  Treatment is by control of diet to avoid products containing phenylalanine and supplementation with tyrosine.