Phenylketonuria

Definition

Phenylketonuria (PKU) is a rare condition in which a baby is born without the ability to properly break down an amino acid called phenylalanine.

Alternative Names

PKU; Neonatal phenylketonuria

Causes

Phenylketonuria (PKU) is inherited, which means it is passed down through families. Both parents must pass on the defective gene in order for a baby to have the condition. This is called an autosomal recessive trait.

Babies with PKU are missing an enzyme called phenylalanine hydroxylase, which is needed to break down an essential amino acid called phenylalanine. The substance is found in foods that contain protein.

Without the enzyme, levels of phenylalanine and two closely-related substances build up in the body. These substances are harmful to the central nervous system and cause brain damage.

References

American Dietetic Association. Providing nutrition services for infants, children, and adults with developmental disabilities and special health care needs. J Am Diet Assoc. Jan 2004; 104(1): 97-107.

Beblo S. Effect of fish oil supplementation on fatty acid status, coordination, and fine motor skills in children with phenylketonuria. J Pediatr. May 2007; 150(5): 479-84.

Filiano JJ. Neurometabolic diseases in the newborn. Clin Perinatol. Jun 2006; 33(2): 411-79.

Gassio R. School performance in early and continuously treated phenylketonuria. Pediatr Neurol. Oct 2005; 33(4): 267-71.

Welch T. Dietary management of mothers with PKU during pregnancy. J Pediatr. Feb 2004; 144(2); 1A.

Welch TR. Pharmacologic approach to PKU? J Pediatr. Jun 2007; 150(6); A3.