Which of the following best describes the relationship between phenylketonuria (PKU) and amino acid deficiency?

• A. PKU leads to a deficiency of all essential amino acids.
• B. PKU results in an inability to metabolize the amino acid phenylalanine, potentially causing a deficiency in tyrosine.
• C. PKU causes the body to overproduce amino acids, leading to toxicity.
• D. PKU is unrelated to amino acid metabolism and affects only carbohydrate digestion.

Answer: (B)