The History of PKU Disease

PKU is the abbreviation for phenylketonuria, a genetic metabolism error that is present at birth. According to the March of Dimes, 1 in 25,000 babies in the United States is affected. Phenylalanine is a part of a protein that can not be broken down into other elements that the body needs. It then builds up in the bloodstream, causing mental retardation. All newborns in the United States are routinely tested for PKU, and nearly all cases are caught and treated. However, this was not always true.

Discovery of PKU

Prior to 1934, an unknown disease caused people to have devastating, permanent mental disabilities. Dr. Asbjorn Folling was the first to identify the cause. He noticed that the patients with these symptoms all had a particular odor, which he identified as being due to high levels of phenylpyruvic acid, a phenylketone, in the urine. The condition was so named because of this discovery. Dr. Folling also suspected that the cause was genetic and that dietary modifications might help.

Initial Management

In 1951, a protein drink developed by Professor Horst Bickel was introduced. It did not taste very good but was the first hope that those affected by PKU might lead mostly normal lives. Strict and difficult dietary management alone continued to be the standard course of treatment until 2007.

Diagnostic Testing

In 1958, a blood test to screen newborns was implemented. Called the Guthrie test--after its discoverer, Robert Guthrie--it was an easy and affordable test requiring four teaspoons of blood. In 1966, the test became standard practice for all hospitals in the United States and is still performed on every newborn today (although modern tests now only require a drop of blood from the newborn's heel).

Management Today

It was in 2007 that BioMarin Pharmaceutical, Inc. introduced the newly approved drug Kuvan. Kuvan is a tablet that reduces blood levels of phenylalanine and is used in conjunction with phenylalanine- (or "Phe") restricted diets.

Misconceptions

Parents of newly diagnosed infants may be concerned that management will be difficult. It is a common mistake to think that people with PKU may not consume any protein. Only a specific protein needs to be limited--the amino acid phenylalanine. There are specific infant formulas created for babies with PKU, and as the individuals grow, they will work with dietitians to create a plan for limiting phenylalanines. It was once thought that phenylalanines needed only to be restricted while the brain was in its growing stages, but it is now recommended that the diet be followed throughout life.