highest incidence in the world with approximately 1 in 2600 births. However, the disease is also common among people of north European descent and less common among Jewish, Asian, and African-American families. Tests available for the detection of phenylketonuria include a enzyme assay to detect the carrier state in parents, chorionic villus sampling to detect fetal PKU, and PKU screening which is mandatory in most states in the United States. Testing is imperative since there are no known signs of Phenylketonuria present in a newborn baby. Untreated PKU can cause symptoms that include: eczema, microcephaly (small head), tremors, spasticity, unusual hand posturing, seizures, hyperactivity, delayed mental and social skills, mental retardation, a “mousy odor” detected on the individual’s breath, skin, and urine, and light coloration (light complexion, blond hair, and blue eyes) in the first year of life. The longer the disease goes on undiagnosed and untreated the more severe the symptoms and mental retardation become in the child. For this reason, testing must be done to determine whether or not the child is affected with PKU. In the 1960s, based on work funded for by the March of Dimes, a test was developed for Phenylketonuria by Dr. Robert Guthrie. All states now routinely test all babies for Phenylketonuria at about 3 days of age, before they ever even leave the hospital. The Guthrie test, which costs on average $1.25, involves pricking the heel of the baby to obtain a few drops of blood. The blood is placed on filter paper and is then sent to a laboratory to find out if it has more than a normal amount of phenylalanine by examining the bacterial metabolism of Bacellus subtiles. If the test results show phenylalanine levels exceed 4 mg/dl then the patient is reported to the health care provider and more testing is completed to determine whether the baby truly has PKU. Repeated testing is important because ...
