endocrinology PKU screening in Iran

Phenylketonuria (PKU) has been diagnosed through newborn screening (NBS) programs in the United States and many European countries since ۱۹۶۰. In Iran, NBS for hyperphenylalaninemia (HPA) and classical PKU was established in ۲۰۰۷, and it was extended to include non-classical PKU in ۲۰۱۰. The primary objectives of NBS are to identify PKU in newborns to reduce mortality and morbidity, prenatal diagnosis and possible abortion of affected fetuses, and improved control and follow-up for late-diagnosed cases. NBS is performed using a colorimetric method on a filter paper between ۳ and ۵ days of life. If the phenylalanine (PA) level exceeds ۱۲۰ μmol/L, it is further tested using HPLC. If the PA level is more than ۱۲۰ μmol/L, the newborn undergoes testing for Neopterin and Biopterin in their urine, and DHPR activity is measured to exclude non-classical PKU. MS/MS may replace the method of screening in the near future. The primary treatment for classical PKU involves a lifelong diet low in PA to control PA levels. This diet should provide all the necessary micronutrients and ensure normal growth. It should be palatable and consistent with a normal quality of life. However, achieving this can be challenging, so educating patients, families, and caregivers is crucial. The treatment for non- classical PKU depends on the specific deficiency. In ۶-pyruvoyltetrahydropterin synthase deficiency, tetrahydropterin (kuvan) is used. In Dihydropterin reductase deficiency, a low PA diet, L-DOPA, ۵-hydroxytryptophan, and folinic acid are prescribed. The follow-up treatment for PKU in Iran aims to maintain PA levels between ۲ and ۶ mg/dL until the age of ۱۲, and then between ۲ and ۱۰ mg/dL thereafter. PA levels below ۲ mg/dL are strictly prohibited, as PA is an essential amino acid. To achieve these targets, patients receive regular visits to PKU referral centers, and it is a collaborative effort involving endocrinologists, neurologists, psychiatrists, nutritionists, and geneticists. In the evaluation of a system with a coverage rate of ۹۸.۵%, the incidence of PKU in Iran has been estimated to be ۱ in ۵,۴۵۵ live births. The incidence of non-classical PKU has been ۷%, which is significantly higher than in the United States and European countries