Phenylketonuria caused by deficiency of

(C) Phenyalanine hydroxylase # Phenylketonuria is a genetic disorder inherited from a person's parents.> It is due to mutations in the PAH gene which results in low levels of the enzyme phenylalanine hydroxylase.> This results in the build up of dietary phenylalanine to potentially toxic levels. It is autosomal recessive meaning that both copies of the gene must be mutated for the condition to develop.> There are two main types, classic PKU and variant PKU, depending on if any enzyme function remains.> Those with one copy of a mutated gene typically do not have symptoms.