Identifying Clinical and Genetic Characteristics of Spinal Muscular Atrophy Patients and Families in Saudi Arabia

Introduction: Spinal muscular atrophy (SMA) is an inherited, neuromuscular disease characterized by the deterioration of spinal motor neurons, causing progressive muscular atrophy and weakening. It is an autosomal recessive disease with the mutation of the survival motor neuron 1 (SMN1) gene as a hallmark. Evidence suggests that the SMN2 gene modulates the severity of the disease. SMA is classified based on the maximum motor function achieved. This study aims to describe the genetic makeup and characteristics of an SMA cohort in the Kingdom of Saudi Arabia (KSA). Methods: Data from families presenting with SMA children was collected between January 2018 and December 2020. Blood samples were collected from patients and family members. Genetic testing for SMA and mutations was performed at a European central lab. Results and discussion: Seventeen families were enrolled in the study, including 52 children. Among 34 parents, 28 were carriers with heterozygous deletion (82.3%), one (2.9%) had no deletion detected by multiplex ligation-dependent probe amplification (MLPA) but had point mutation by sequencing, one (2.9%) had homozygous deletion and was symptomatic, three (8.8%) had no deletion or point mutation and were presumed to have 2+0, and one (2.9%) was not tested. Conclusion: This study provides insight into the carrier mutational analysis of families with SMA disease manifestations in KSA. Further studies are needed to understand the burden and impact of SMA among the Saudi population.