PKU stands for?

• A. Protein kinase unit
• B. Pyruvate kinase deficiency
• C. Pyridoxine deficiency
• D. Phenylketonuria

Answer: (D)

PKU stands for Phenylketonuria, an inherited metabolic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase. Because phenylalanine cannot be properly converted to tyrosine, it builds up in the blood and brain, which can lead to intellectual disability and other complications if not treated early. In nutrition-focused care, this means a lifelong diet low in phenylalanine and the use of specialized medical foods, especially important for infants and children. Newborn screening is used to detect PKU so treatment can begin promptly. The other options refer to different concepts: a term related to enzymes, a distinct enzyme deficiency affecting red blood cells, and a vitamin B6 deficiency.