Osmosis video - Phenylketonuria (NORD)

Phenylketonuria (PKU) is an autosomal recessive amino acid metabolism disorder involving impaired metabolism of the amino acid phenylalanine, caused by the absence or reduced activity of phenylalanine hydroxylase. In PKU toxic levels of phenylalanine and phenylketone build up in the body and tyrosine levels drop.

Symptoms include a musty odor of sweat and urine, intellectual disability, seizures, behavioral problems, and other neurological symptoms. In pregnant females, PKU can affect the fetus - causing heart disease, growth problems, intellectual disability, and microcephaly. Treatment is based on a diet with low levels of phenylalanine and supplementing with tyrosine and tetrahydrobiopterin.