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

PKU leads to a deficiency of all essential amino acids.

PKU results in an inability to metabolize the amino acid phenylalanine, potentially causing a deficiency in tyrosine.

PKU causes the body to overproduce amino acids, leading to toxicity.

PKU is unrelated to amino acid metabolism and affects only carbohydrate digestion.