National PKU is dedicated to providing resources and education for professionals and families managing Phenylketonuria (PKU), a rare genetic metabolic disorder which inhibits the body's ability to metabolize phenylalanine, one of the amino acids in protein. Those with PKU must follow a severely protein-restricted diet and consume a medical formula to complete their nutrition for their entire lives. Our HowMuchPhe.org project is the premier diet management tool for PKU.