Phenylketonuria (PKU)

Phenylketonuria is an inherited disorder that increases the levels of a substance called phenylalanine in the blood.

Classic PKU presents normally until the infant is a few months old. Without treatment, these children develop permanent intellectual disability. Seizures, delayed development, behavioral problems, and psychiatric disorders are also common. Other, less severe forms have a smaller risk of brain damage. Untreated individuals may have a musty or mouse-like odor as a side effect of excess phenylalanine in the body.