Phenylketonuria is caused by
A) an inherited lack of an enzyme.
B) neurofibrillary tangles.
C) toxic chemicals released by a virus.
D) accumulation of waste products in the brain.
E) prenatal exposure to rubella.

Question

Quizplus · Accepted Answer

Phenylketonuria (PKU) is caused by an inherited lack of the enzyme phenylalanine hydroxylase, which is needed to break down the amino acid phenylalanine. As a result, phenylalanine and its byproduct, phenylpyruvic acid, can build up in the body and cause neurological problems if left untreated.

Phenylketonuria Is Caused by