Question

Regarding the assertion and reason, choose the correct option.

Assertion [A]: Individuals affected with phenylketonuria exhibit mental retardation.

Reason [R]: The affected individuals lack an enzyme, phenylalanine hydroxylase which results in accumulation of phenylalanine in the body

• A. Both A and R are correct and R explains A
• B. Both A and R are correct but R does not explain A
• C. A is correct and R is incorrect
• D. Both A and R are incorrect

Answer 1

The correct option is A

Both A and R are correct and R explains A

Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. The affected individuals of phenylketonuria lack phenylalanine hydroxylase that converts phenylalanine into tyrosine. Accumulation of phenylalanine which is converted into phenylpyruvic acid in the brain results in mental retardation.