Incidence of Neonatal Hyperphenylalaninemia in Fars Province, Southern Iran

Objective: phenylalanine hydroxylase or its cofactor, tetrahydrobiopterin (bh4), deficiency causes accumulation of phenylalanine in body fluids and central nervous system. considering the fact that hyperphenylalaninemia is a preventable cause of mental retardation in infants, the objective of this study was to determine the incidence of congenital hyperphenylalaninemia in fars province, south of iran.methods: in a period of one year from november 2007 to november 2008 blood samples were withdrawn from all newborns born in fars province for measurement of serum phenylalanine. the samples with a serum level of ³ 2 mg/dl were referred to pediatric endocrine clinic for confirmation and determination of the type of hyperphenylalaninemia by quantitive serum phenylalanine measurements by using high-pressure liquid chromatography (hplc) method.findings: nine out of 76966 newborns had a serum phenylalanine level ³2mg/dl, of which 8 cases were confirmed by hplc. the incidence of the disease was 1:10000. the incidence of mild hyperphenylalaninemia and phenylketonuria (pku) among the patients was 62.5% and 37.5% respectively and the incidence of bh4 deficiency was 1/76966. conclusion: these findings indicate a high incidence of hyperphenylalaninemia, in the newborns from fars province. the high incidence makes a comprehensive screening program for management of the disease necessary.