phenylketonuria

A genetic disorder in which the body lacks the enzyme necessary to metabolize phenylalanine to tyrosine. Left untreated, the disorder can cause brain damage and progressive mental retardation as a result of the accumulation of phenylalanine and its breakdown products.

A metabolic disorder in which individuals lack the liver enzyme phenylalanine hydroxylase (PAH) which is needed to metabolize the amino acid phenylalanine.

a genetic disorder of metabolism; lack of the enzyme needed to turn phenylalanine into tyrosine results in an accumulation of phenylalanine in the body fluids which causes various degrees of mental deficiency