U.S. flag

An official website of the United States government

GTR Home > Conditions/Phenotypes > Mild phenylketonuria


A mild to moderate form of phenylketouria (PKU), an inborn error of amino acid metabolism, characterized by blood phenylalanine concentrations of 600-1,200 micromol/L and manifests with reduced cognitive function and behavioral and developmental disorders. Dietary phenylalanine tolerance is 400-600 mg/day. [from ORDO]

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.