Introduction and objectives
Spinocerebellar 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 methods
At 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.
Two novel pathogenic variants were identified in the SACS gene, and the diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was established.
This is the first report of spastic ataxia of Charlevoix-Saguenay cases in Mexico.