How Is Phenylketonuria Diagnosed?
Almost all babies born in hospitals in the United States are screened for PKU within 48 hours of birth with a blood test that measures their levels of phenylalanine. In families with a history of PKU, the disease can usually be diagnosed in the fetus during pregnancy. A pregnant woman who has untreated PKU herself has a much greater chance of having a baby with (often severe) birth defects.
Living with Phenylketonuria
Jennifer is a happy 12-year-old with fair skin, blue eyes, and a very normal life except for her diet. Jennifer has PKU, which was diagnosed at birth through hospital screening. She cannot go out for pizza, drink diet sodas, or eat many of the common foods that most people take for granted.
Infants with PKU must begin treatment within days of being born to prevent intellectual disabilities. They must eat a special diet that restricts their intake of phenylalanine and provides the tyrosine that the body cannot make. Babies drink special formula * that is low in phenylalanine. People with PKU cannot have high-protein foods such as meat, poultry, fish, milk, eggs, and cheese or products containing the artificial sweetener aspartame (also known by the brand name NutraSweet). They can eat low-protein foods such as fruits, vegetables, and certain cereals.
Not adhering to the diet may cause serious problems such as a drop in IQ and problems with learning and behavior. Experts are not sure whether and at what age it is safe to stop treatment. Most recommend that people with PKU stay on the special diet for life.
See also Birth Defects: Overview • Genetic Diseases: Overview • Intellectual Disability • Metabolic Disease • Seizures • Skin Conditions: Overview
Resources
Paul, Diane B., and Jeffrey P. Brosco. The PKU Paradox: A Short History of a Genetic Disease. Baltimore, MD: Johns Hopkins University Press, 2013.
Genetics Home Reference. “Phenylketonuria.” National Institutes of Health. http://ghr.nlm.nih.gov/condition/phenylketonuria (accessed November 11, 2015).
March of Dimes. “PKU (Phenylketonuria) in Your Baby.” http://www.marchofdimes.org/baby/phenylketonuria-in-your-baby.aspx (accessed August 11, 2015).
MedlinePlus. “Phenylketonuria.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/phenylketonuria.html (accessed November 11, 2015).
Children's PKU Network. 3306 Bumann Rd., Encinitas, CA 92024. Telephone: 858-756-0079. Website: http://www.pkunetwork.org/Childrens_PKU_Network/Home.html (accessed August 11, 2015).
March of Dimes. 1275 Mamaroneck Ave., White Plains, NY 10605. Telephone: 914-997-4488. Website: http://www.marchofdimes.org (accessed November 11, 2015).
National PKU Alliance. PO Box 501, Tomahawk, WI 54487. Telephone: 715-437-0477. Website: http://npkua.org/Home.aspx (accessed August 11, 2015).
* metabolism (meh-TAB-o-liz-um) is the process in the body that converts food into the energy necessary for body functions.
* enzyme (EN-zime) is a protein that helps speed up a chemical reaction in cells or organisms.
* amino acids (a-MEE-no acids) are the chief building blocks of proteins. In humans, certain amino acids are required to sustain life.
* eczema (EG-ze-mah) is an inflammatory skin condition characterized by redness, itchiness, and oozing blisters that become crusty and hard.
* seizures (SEE-zhurs), also called convulsions, are sudden bursts of disorganized electrical activity that interrupt the normal functioning of the brain, often leading to uncontrolled movements in the body and sometimes a temporary change in consciousness.
* hyperactivity (hy-per-ak-TI-vi-tee) is overly active behavior, which makes it hard for a person to sit still.
* formula is a prepared, nutritious drink or a dry drink mix designed