Identification of SOD1 Gene Variants in Mexican Patients with Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic Lateral Sclerosis (ALS) is a rapidly progressing, fatal neurodegenerative disorder that selectively affects motor neurons. Clinical manifestations include progressive muscle weakness, amyotrophy, fasciculations, dysphagia, and fatal respiratory failure. The median survival after symptom onset is typically 2 to 5 years. Despite its severity, the epidemiological profile and genetic landscape of ALS in Latin American populations, particularly in Mexico, remain unclear. In this study, we evaluated the mutational spectrum of the SOD1 gene in a Mexican cohort of 156 ALS patients. Using high-resolution melting (HRM) analysis and Sanger sequencing, we identified 22 SOD1 variants in 42 of 156 patients (overall variant carrier frequency, 26.92%). Pathogenic or likely pathogenic (P/LP) variants were found in 21 patients (13.5%). Notably, 5 of the 22 variants were novel, expanding the spectrum of SOD1 variants. The variant carrier frequency identified in this study is higher than that reported for European populations but similar to frequencies observed in Asian populations. Our results highlight the distinct genetic heterogeneity of ALS in Mexico and demonstrate that HRM is a rapid and effective method for identifying SOD1 gene variants.