What is the most common symptom of PKU?

The most common symptom of phenylketonuria (PKU) is intellectual disability, which can develop if the condition is not diagnosed and treated early. Other symptoms may include developmental delays, behavioral problems, and seizures. Individuals with PKU may also exhibit a musty or mousy odor due to the buildup of phenylalanine in the body. Early detection through newborn screening and strict dietary management can help prevent the severe effects of the disorder.