Comparison of the clinical and genetic features of amyotrophic lateral sclerosis across Cuban, Uruguayan and Irish clinic-based populations.

Abstract

This study compares the clinical characteristics of patients with amyotrophic lateral sclerosis (ALS) within three clinic-based populations from Cuba, Uruguay and Ireland and determines the impact of known ALS-associated genetic variants on phenotypic manifestations within the Cuban population. Demographic and clinical information was collected on 115 Cuban, 220 Uruguayan and 1038 Irish patients with ALS attending national specialist clinics through 1996-2017. All Cuban patients and 676 Irish patients underwent next-generation DNA sequencing and were screened for the pathogenic <i>C9orf72</i> repeat expansion. The mean age of onset was younger in the Cuban (53.0 years, 95% CI 50.4 to 55.6) and Uruguayan (58.2 years, 95% CI 56.5 to 60.0) populations compared with the Irish population (61.6 years, 95% CI 60.9 to 62.4). No differences in survival between populations were observed. 1.7 % (95% CI 0.6 to 4.1) of Cubans with ALS carried the <i>C9orf72</i> repeat expansion compared with 9.9% (95% CI 7.8 to 12.0) of Irish patients with ALS (p=0.004). Other known variants identified in the Cuban population included <i>ANG</i> (one patient), <i>CHCHD10</i> (one patient) and <i>DCTN1</i> (three patients). This study is the first to describe the clinical characteristics of ALS in Cuban and Uruguayan populations and report differences between the Cuban and Irish genetic signature in terms of known ALS-associated genetic variants. These novel clinical and genetic data add to our understanding of ALS across different and understudied populations.