What is PKU?

What is PKU?
Phenylketonuria is an autosomal recessive genetic metabolic disorder that greatly reduces the ability of those affected to metabolize phenylalanine, one of the amino acids in protein. A buildup of phenylalanine (phe) in the blood can cause profound damage to the central nervous system in children and adults. If untreated in newborns, PKU can cause irreversible brain damage within months. Lifelong treatment is required to prevent neurological and physical deterioration.

How is it diagnosed?
In the United States, PKU is diagnosed through life-saving Newborn Screening, which is mandatory in all 50 states. In the early 1960s, Dr. Robert Guthrie developed the “heel-prick test,” where blood is taken from babies at birth and screened (now more than 77 diseases) because early detection of PKU is vital to prevent brain damage. PKU is a very rare disease. In the United States, approximately 250 babies are born each year with PKU.

How is it treated?
Individuals with PKU must maintain a life-long protein-restricted diet (as little as 4 grams per day) while drinking a metabolic formula that provides the protein (minus phenylalanine) that is absent from their diet, along with other nutrients. Regular blood tests help determine whether the phe levels in the blood are within a safe range, and diets are adjusted to allow for changes through an individual’s life. There is one available medicine, Kuvan, which can improve some individuals’ ability to metabolize phe, and another, Peg-Pal, which is currently in clinical trials. These treatments do not work for all individuals.