Epidemiology of inherited metabolic disorders in newborn screening: insights from three years of experience in Southern Iran.

backgroundNewborn screening is essential for the early detection of congenital genetic and metabolic disorders, enabling timely intervention to prevent morbidity, mortality, and disabilities associated with inherited metabolic disorders (IMDs). The Iranian Neonatal Screening Program piloted in Fars Province, screening nearly 100% of neonates for 20 disorders. This study aimed to assess the epidemiology of these metabolic diseases. From March 2019 to September 2021, 138,689 neonates were screened using tandem mass spectrometry (MS/MS) on dried blood spots. Those with abnormal results were referred to pediatric endocrinology and metabolism specialists for confirmatory testing per American College of Medical Genetics guidelines.

resultsAmong the screened neonates, 139 patients of IMDs were identified, yielding an estimated birth prevalence of 1:1000. The positive cases included 55 aminoacidopathies, 47 organic acidemias, 31 fatty acid oxidation disorders, and 6 urea cycle defects were detected. The most prevalent IMDs were phenylalanine metabolism disorders, short-chain acyl-CoA dehydrogenase deficiency, 3-methylcrotonyl-CoA carboxylase deficiency, and methylmalonic acidemia. Notably, the prevalence of IMDs in Fars Province is significantly higher than average global statistics. Additionally, we observed that certain disorders previously deemed very rare exhibit a relatively high prevalence in this region.

conclusionsOur data highlight the efficiency and robustness of neonatal screening for IMD in Iran. It demonstrates the need for expanded screening efforts across the entire country. One limitation of this study is that the screening was conducted in only one state, which may not reflect the broader population of Iran. Future research should involve nationwide implementation of screening programs to validate our findings and assess the prevalence of IMDs in diverse regions. Furthermore, exploring the applicability of our screening methods in other Middle Eastern countries could help promote early and life-changing diagnoses across the region.