Phenylalanine Hydroxylase Deficiency (PAH) - Diseases and Conditions Identified in Children

Phenylalanine Hydroxylase Deficiency (PAH), traditionally known as phenylketonuria (PKU) or hyperphenylalaninemia(H-PHE)


Phenylalanine hydroxylase deficiency (PAH) is an inborn error of metabolism, an inherited condition in which an enzyme, phenylalanine hydroxylase, in the body is either missing or not working well. PAH deficiency describes a spectrum of findings traditionally known as the conditions phenylketonuria (PKU) or hyperphenylalaninemia (H-PHE). The job of the phenylalanine hydroxylase enzyme is to break down the amino acid (a part of protein) known as phenylalanine. When this enzyme is not working well phenylalanine builds up in the body. How much phenylalanine builds up in the body can vary from person to person with PAH deficiency. Phenylalanine levels that rise too high are toxic to the brain. Early detection, prompt treatment and careful, ongoing management of PAH deficiency can successfully lower phenylalanine levels that get too high, thereby preventing the most serious health and developmental concerns. People with PAH deficiency benefit greatly from early detection and management. Support groups are available to help connect families living with PAH deficiency with others who have experience or expertise with this condition.

To learn more about Phenylalanine Hydroxylase Deficiency (PAH), visit Screening, Technology, and Research in Genetics (STAR-G): Phenylketonuria, Baby's First Test: Classic Phenylketonuria and Baby's First Test: Benign Hyperphenylalaninemia. A listing of contact information for Minnesota inborn errors of metabolism medical specialty providers/clinics serving children affected with or undergoing evaluation for conditions that can be detected through Minnesota Newborn Screening is available upon request.