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What are common symptoms of phenylketonuria (PKU)?

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Children with untreated PKU appear normal at birth. But by age 3 to 6 months, they begin to lose interest in their surroundings. By age 1 year, children are developmentally delayed and their skin has less pigmentation than someone without the condition. If people with PKU do not restrict the phenylalanine in their diet, they develop severe intellectual and developmental disabilities.

Other symptoms include:

  • Behavioral or social problems
  • Seizures, shaking, or jerking movements in the arms and legs
  • Stunted or slow growth
  • Skin rashes, like eczema (pronounced EK-suh-muh)
  • Small head size, called microcephaly (pronounced mahy-kroh-SEF-uh-lee)
  • A musty odor in urine, breath, or skin that is a result of the extra phenylalanine in the body
  • Fair skin and blue eyes, due to the body's failure to transform phenylalanine into melanin, the pigment responsible for a person's coloring1

  1. Genetics Home Reference. (2012). Phenylketonuria. Retrieved June 22, 2012, from http://ghr.nlm.nih.gov/condition=phenylketonuria [top]

Last Updated Date: 10/23/2013
Last Reviewed Date: 08/23/2013
Vision National Institutes of Health Home BOND National Institues of Health Home Home Storz Lab: Section on Environmental Gene Regulation Home Machner Lab: Unit on Microbial Pathogenesis Home Division of Intramural Population Health Research Home Bonifacino Lab: Section on Intracellular Protein Trafficking Home Lilly Lab: Section on Gamete Development Home Lippincott-Schwartz Lab: Section on Organelle Biology