National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Phenylketonuria is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
- Classical Phenylketonuria
- Phenylalanine Hydroxylase Deficiency
Phenylketonuria (PKU) is an inborn error of metabolism that is detectable during the first days of life with appropriate blood testing (e.g., during routine neonatal screening). PKU is characterized by absence or deficiency of an enzyme (phenylalanine hydroxylase) that is responsible for processing the essential amino acid phenylalanine. (Amino acids, the chemical building blocks of proteins, are essential for proper growth and development.) With normal enzymatic activity, phenylalanine is converted to another amino acid (tyrosine), which is then utilized by the body. However, when the phenylalanine hydroxylase enzyme is absent or deficient, phenylalanine abnormally accumulates in the blood and is toxic to brain tissue.
Symptoms associated with PKU are typically absent in newborns. Affected infants may be abnormally drowsy and listless (lethargic) and have difficulties feeding. In addition, untreated infants with PKU tend to have unusually light eyes, skin, and hair (light pigmentation) and may develop a rash that appears similar to eczema, an inflammatory skin condition that may be characterized by itching, redness, and blistering in affected areas.
Without treatment, most infants with PKU develop mental retardation that is typically severe. Those with untreated PKU may also develop additional neurologic symptoms, such as episodes of uncontrolled electrical activity in the brain (seizures), abnormally increased activity (hyperactivity), poor coordination and a clumsy manner of walking (gait), abnormal posturing, aggressive behavior, or psychiatric disturbances. Additional symptoms and findings may include nausea, vomiting, and a musty or "mousy" body odor due to the presence of a by-product of phenylalanine (phenylacetic acid) in the urine and sweat.
To prevent mental retardation, treatment consists of a carefully controlled, phenylalanine-restricted diet beginning during the first days or weeks of life. Most experts suggest that a phenylalanine-restricted diet should be lifelong in persons with classical PKU. Classical PKU refers to persons with 2 severe mutations of the phenylalanine hydroxylase gene.
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
National PKU News
6869 Woodlawn Avenue NE #116
Seattle, WA 98115-5469
Children's PKU Network
3790 Via De La Valle, Ste 120
Del Mar, CA 92014
National Institute of Mental Retardation
Kinsmen NIMR Building
4700 Keele Street
North York, Toronto
Ontario, M3J 1P3
Phenylalanine Hydroxylase Locus Knowledgebase (PAHdb)
McGill Univeristy Health Center
Montreal Children's Hospital
DeBelle Laboratory, Room A717
2300 Tupper St.
Monteral, Quebec, H3H 1P3
NIH/National Institute of Child Health and Human Development
31 Center Dr
Building 31, Room 2A32
Bethesda, MD 20892
Cochrane Cystic Fibrosis and Genetic Disorders Group
Institute of Child Health, University of Liverpool
Alder Hey Children's NHS Foundation Trust
Liverpool, L12 2 AP
Tel: +44 (0) 151 252 5696
Fax: +44 (0) 151 252 5456
MUMS National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
Belgian Association for Metabolic Diseases (BOKS)
Alice Nahonlann 7
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Mid-Atlantic Connection for PKU and Allied Disorders, Inc.
PO Box 6086
Lancaster, PA 17607-6086
PO Box 241956
Los Angeles, CA 90024
Cook for Love, Inc.
30 Seneca Street
Dobbs Ferry, NY 10522
National PKU Alliance
P.O. Box 501
Tomahawk, WI 54487-0501
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This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html