Phenylketonuria from genetics to clinics: An Iranian prospect

Document Type : Review Paper


1 Division of Genetics, Department of Biology, Faculty of Science, University of Isfahan, P.O. Box 81746-73441, Isfahan, I.R. Iran.

2 Department of Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, P.O. Box 19395-4719, Tehran, I.R. Iran.


Phenylketonuria (PKU) is the most common autosomal recessive disorder of amino acid metabolism. The
disease is caused mainly by mutations in the phenylalanine hydroxylase (PAH) gene, encoding phenylalanine
hydroxylase (PAH) enzyme. The PAH enzyme deficiency results in the elevation of phenylalanine in
the blood, which may cause severe irreversible mental retardation in the affected individuals. More than 500
different disease causing mutations have been identified in the PAH gene. Direct and indirect molecular
approaches have been developed for carrier detection and prenatal diagnosis of PKU disease. Population
distribution of the PAH gene mutations and the PKU disease varies in different countries. In view of relatively
high prevalence of the disease in Iranian population, investigations toward the elucidation of molecular
aspects of the disease were required. In the present article, clinical and molecular basis of the PKU disease,
with emphasis on the studies performed in Iranian population, were reviewed.