(HealthDay)—Palynziq (pegvaliase-pqpz) has been approved by the U.S. Food and Drug Administration to treat phenylketonuria, commonly called PKU. People with the rare yet serious inherited disorder can’t break down an amino acid called phenylalanine, which is found in many sweeteners and protein-containing foods. The disorder affects about 1 in 10,000 to 15,000 people in the...