Congenital Myasthenic Syndrome Associated With SLC25A1 Gene Variant: The First Reported Case in Saudi Arabia

We report the case of a two-year-old full-term girl of consanguineous Saudi parents, who had a history of poor sucking, hypotonia, and bilateral ptosis, as well as recurrent pediatric intensive care unit (PICU) admissions with apnea and global developmental delay and unremarkable family history. A genetic study was conducted and whole exome sequencing (WES) identified a likely pathogenic homozygous variant c.842C>T p.(Ala281Val) in the SLC25A1 gene. This finding is consistent with the genetic diagnosis of autosomal recessive combined D-2- and L-2-hydroxyglutaric aciduria (D/L-2-HGA). Genetic testing results suggested a diagnosis of congenital myasthenic syndrome (CMS) type 23 [Online Mendelian Inheritance in Man (OMIM) #618197]. CMS is a highly heterogeneous group of neuromuscular junction (NMJ) disorders clinically and genetically and compromises the safety margin required for reliable neuromuscular transmission. Fortunately, we suspected a CMS in our patient, and the initiation of management with pyridostigmine has substantially improved the patient's condition.