First report of spastic ataxia of Charlevoix-Saguenay cases in Mexico. Novel SACS gene mutations identified

Abstract

Introduction and objectivesSpinocerebellar ataxia autosomal recessive (SCAR) represents a heterogeneous chronic and progressive neurological diseases group. They usually occur at an early age in a progressive manner. Diagnosis is complex due to phenotypic overlap. SCARs account for more than 50% of all ataxia cases of genetic origin, with a prevalence of 3–4/100 000. According to international published series, Friedreich's ataxia (FA) is the most common. In Mexico, more than 90% of patients with suspected SCAR remain without etiologic diagnosis after ruling out FA and acquired causes of ataxia. Our main goal was to reach a diagnosis using genomic tools in this group of patients. Materials and methodsAt the National Institute of Genomic Medicine, we used next-generation sequencing as a diagnostic tool in 4 patients with a clinical diagnosis of SCAR to identify and classify etiologic variants responsible for this group of disorders. ResultsTwo novel pathogenic variants were identified in the SACS gene, and the diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was established. ConclusionsThis is the first report of spastic ataxia of Charlevoix-Saguenay cases in Mexico.