Supplemental phenylketonuria therapies may help some

Research Activities, June 2012, No. 382

Evidence supports lifelong dietary management of Phenylketonuria (PKU) concludes a new research review from the Effective Health Care Program of the Agency for Healthcare Research and Quality (AHRQ). The report confirms that PKU is a rare metabolic disorder that, if uncontrolled, leads to a toxic buildup of the amino acid phenylalanine (Phe) in the blood. This results in intellectual disability, delayed speech, seizures, and behavioral abnormalities. PKU strikes approximately 1 in 13,500 to 19,000 newborns in the United States.

Standard treatment for PKU is a lifelong diet that restricts intake of Phe to control Phe levels in the blood. The review supports the commonly used blood Phe target of 120 to 360 µmol/L. However, two adjuvant treatments intended to control blood Phe concentrations, sapropterin dihydrochloride (BH4), and large neutral amino acids (LNAAs), have the potential to help patients manage their PKU and possibly eat a less stringent diet.

The review found that the supplemental therapy BH4 is effective in reducing levels of Phe in some patients. However, the long-term effects of BH4 are still unknown, though reported harms were few. Evidence is still lacking on the effectiveness of LNAAs as an adjuvant treatment option for reducing Phe levels or increasing Phe tolerance. Adjuvant Treatment for Phenylketonuria (PKU) summarizes evidence on the effectiveness of adjuvant therapies in individuals with PKU, including pregnant women, in reducing Phe levels in the blood and supporting mental and physical functions and quality of life. The review suggests additional research is needed to investigate the effectiveness of these treatments in a variety of patient populations.

To access this review and other materials that explore the effectiveness and risks of treatment options for various conditions, visit AHRQ's Effective Health Care Program Web site.

Page last reviewed June 2012
Internet Citation: Supplemental phenylketonuria therapies may help some: Research Activities, June 2012, No. 382. June 2012. Agency for Healthcare Research and Quality, Rockville, MD.