Spectrum of inborn errors of metabolism: a tertiary hospital-based study in Egypt

Abstract Background Inborn errors of metabolism (IEM) are a phenotypically and genetically variable group of diseases produced by a variety of disorders in the metabolic pathway. They are more common in countries with a high consanguinity rate, such as Egypt. This study aimed to explore the frequency of IEM among eighty children who attend the Metabolic Outpatient Clinic at Alexandria University Children’s Hospital (AUCH) for follow-up from September 2019 to February 2023. Those children has been diagnosed clinically, radiologically and biochemically by using extended metabolic screening including amino acid screen, urine organic acids measurement and tandem mass spectrometry (TMS). Data about age, sex, birth order, area of residence, age at onset, presenting complaints, and family history of the same disease were all collected from caregivers and hospital records. Results There was a male predominance of 46 cases (57.5%), and females accounted for 34 (42.5%). Twenty percent of the studied cases had a history of a similar condition in their family. Specifically, 21 cases (26.3%) had maple syrup urine disease (MSUD), 19 cases (23.8%) had glutaric acidemia (GA) type 1, 13 cases (16.3%) had methylmalonic acidemia (MMA), and 8 (10%) had isovaleric acidemia (IVA). Only 2 cases (2.5%) of the studied cases had fatty acid oxidation defects (FAOD), and there was only one case (1.3%) of 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (HMG-CoA) and one cases (1.3%) of propionic acidemia (PA). Conclusion IEM are frequent among children, and further research studies are needed to gain a better understanding of their nature, highlighting the importance of neonatal screening and timely diagnosis to improve outcomes of affected children. As prevalence of some disorders seem to be more common, it is better to address on newborn screening program (NBS) to address them.