What is the Genetic Defect Responsible for PKU

Question

What is the genetic defect responsible for PKU?
A) A mutation in the PAH gene causes the body to break down phenylalanine more rapidly than normal.
B) A mutation in the PAH gene inactivates the phenylalanine hydroxylase enzyme.
C) A mutation in the PAH gene causes the body to break down the amino acid tyrosine more rapidly than normal.
D) A mutation in the PAH gene causes the body to break down the amino acid tyrosine more slowly than normal.
E) A mutated protein causes the body to convert tyrosine into phenylalanine.

Accepted Answer

PKU is caused by a mutation in the PAH (phenylalanine hydroxylase) gene. This mutation inactivates the enzyme phenylalanine hydroxylase which is responsible for breaking down the amino acid phenylalanine. As a result, phenylalanine accumulates in the body and can cause intellectual disabilities and other neurological problems.