phenylketonuria (fĕnˌəlkētˌənŏrˈēə) [key] (PKU), inherited metabolic disorder caused by a deficiency in a specific enzyme (phenylalanine hydroxylase). The absence of this enzyme, a recessive trait, prevents the body from making use of phenylalanine, one of the amino acids in most protein-rich foods, and almost always leads to mental retardation and schizoid changes when phenylalanine levels rise; convulsions also commonly occur. Early diagnosis and treatment, which includes a carefully regulated low-phenylalanine diet begun during the first few weeks of life, may prevent serious mental deficiency. Positive improvement has been seen even when therapy is started in well-established cases. In 2007 the FDA approved the use of sapropterin dihydrochloride as a treatment. The drug can boost the ability of persons with low levels of phenylalanine hydroxylase to break down phenylalanine but will not help those who lack the enzyme. Most states have made the PKU blood or urine test mandatory for all newborn infants.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on phenylketonuria from Fact Monster:

  • PKU - PKU: PKU: see phenylketonuria.
  • enzyme: Enzyme Deficiency - Enzyme Deficiency A variety of metabolic diseases are now known to be caused by deficiencies or ...
  • mental retardation: Prevention - Prevention Many cases of mental retardation are now prevented by improved health care. Vaccines ...
  • tyrosine - tyrosine tyrosine , organic compound, one of the 20 amino acids commonly found in animal proteins. ...
  • phenylalanine - phenylalanine phenylalanine , organic compound, one of the 22 α-amino acids commonly found in ...

See more Encyclopedia articles on: Pathology

Play Hangman

Play Poptropica

Play Quizzes

Play Tic Tac Toe