Phenylketonuria (pronounced fee-nill-key-toe-NURR-ee-uh) or PKU is a rare, inherited metabolic disorder. Each year, approximately 1 in 14,000 newborn babies are diagnosed with PKU. If you have PKU, your body cannot break down, or metabolize, the essential amino acid, phenylalanine (Phe). Amino acids are the building blocks of protein. The primary treatment for PKU is a special metabolic formula and the restriction of foods high in Phe (protein), such as meats, cheeses, milk, bread and pasta. Life-long dietary compliance is a critical component for proper growth and development in children and quality of life in adults. We hope Penny The Penguin can help your child on this "diet for life" journey.