The progress of phenylalanine hydroxylase gene mutations as well as relationship between genotype and phenotype.

Phenylketonuria(PKUMIM#261600) is the most common inborn error of amino acid metabolism in many countries.It is transmitted in autosomal-recessive pattern.PKU is caused by deficiency of hepatic enzyme phenylalanine hydroxylase(PAHEC 1.14.16.1)which catalyses the conversion of phenylalanine to tyrosine.Defects in PAH enzyme result in the elevated serum level of phenylalanine and mental retardation.The hyperphenylalaninemia phenotype is highly variable ranging from mild hyperphenylalaninemia(MHP) to the most severe form classic PKU.At present 546 mutative alleles and 659 genotypes were found in the worldwhich catalogued in PAHdb database(http//www.pahdb.mcgill.ca).Although phenotype is closely related to genotype several different patients who carried the same mutations are not consistency as to phenotype.this article collected research accomplishments reported in recent years and detailed the aspects including pah gene characteristics PAH enzyme structure gene mutation as well as the relationship between genotype and phenotype.