PAH and phenylketonuria: Phenylketonuria (PKU), OMIM: 261600, an autosomal recessive inherited metabolic disorder caused by mutations of Phenylalanine Hydroxylase enzyme (PAH), which converts phenylalanine (Phe) into tyrosine (Tyr), is characterized by high blood Phe concentrations that cause neurodevelopmental damage if left untreated [1].