Phenylketonuria (PKU) is a lifelong genetic disorder in which a deficient enzyme prevents the body from metabolizing or breaking down one of the normal building blocks of protein. The protein is an essential amino acid, called phenylalanine (Phe) which is found in most foods including meat, bread, eggs, dairy, nuts, and some fruits and vegetables. When left untreated, PKU patients who consume too much Phe are at risk for severe neurological complications, including IQ loss, memory loss, concentration problems, mood disorders, and in some cases, severe intellectual disabilities. PKU affects approximately 13,000 people in the U.S. and 50,000 people worldwide.

What Causes Phenylketonuria?

PKU is a genetic disorder that prevents the body from metabolizing or breaking down the amino acid, Phe.

How Is Phenylketonuria Diagnosed?

Barbara Burton, MD, director of the PKU and metabolic disease program and Lauren Leviton, education coordinator in the Division of Genetics, Birth Defects and Metabolism, lead the adult PKU outreach program at Lurie Children’s. Through the program, the team has been able to identify and treat several adult PKU patients who have returned to treatment.

“It is so important for adults with PKU to know that it is never too late to address the disorder and resume treatment,” says Dr. Burton. “When PKU is no longer managed, we start to see patients who suffer from mood and social disorders. For adults, this can also impact their concentration at work, stability in relationships and social interactions. As a healthcare provider, I feel that it is our responsibility to educate adult PKU patients and offer comprehensive medical care and social support systems.”

How Is Phenylketonuria Treated?

There are new dietary products and formulas for patients with PKU. Also, the FDA recently approved a medication called sapropterin dihydrochloride (KUVAN®) tablets. In clinical trials, sapropterin dihydrochloride has been shown to help control blood Phe levels in PKU patients. Many of the adult patients, who have lost contact with their clinic because they could not maintain the diet anymore, need to be aware that there are many more options.