Which statement about phenylketonuria is false?
A) It arises from a defective enzyme.
B) The allele that causes phenylketonuria has pleiotropic effects.
C) It can lead to mental retardation.
D) It can lead to skin disorders.
E) The allele that causes phenylketonuria has incomplete dominance.

Question

Quizplus · Accepted Answer

The statement that the allele that causes phenylketonuria has incomplete dominance is false. PKU is an example of a recessively inherited disorder, meaning an individual must inherit two copies of the defective gene (one from each parent) to express the condition. The defective gene codes for an enzyme called phenylalanine hydroxylase, which is responsible for converting the amino acid phenylalanine to another amino acid called tyrosine. Without this enzyme, phenylalanine builds up in the body and can cause neurological damage, leading to mental retardation. Additionally, phenylalanine can be converted into other harmful compounds in the body, leading to skin disorders, among other symptoms.

Which Statement About Phenylketonuria Is False