Demographics and Clinical Characteristics of Autosomal Dominant Spinocerebellar Ataxia in Canada

Abstract

Background Autosomal dominant (AD) spinocerebellar ataxias (SCAs) encompass a large group of rare disorders, which occurs in individuals of different ethnic backgrounds. To date, demographics, and clinical descriptions of AD SCA in Canada are lacking. Methods A retrospective chart review of patients with a genetically confirmed diagnosis of AD SCAs was performed at five tertiary centers across Canada in the provinces of Quebec, Alberta, and Ontario. Demographic, genetic, and clinical information were collected and analyzed. Results A total of 203 patients with AD SCA were identified. Weighted estimated prevalence of AD SCA in three large Canadian provinces was calculated (2.25 cases per 100.000) which is in keeping with the figures documented worldwide. We found that the distribution of the most common SCA differed when comparing provinces. The most prevalent SCA diagnosis in Ontario was SCA3 (49%), while the most prevalent SCA diagnosis in Alberta and Quebec was SCA2 in 26% and 47%, respectively. SCA6 was the third most prevalent SCA subtype in Quebec (14%), which was not seen as commonly in other provinces. SCA1 was uncommonly seen in both Alberta and Quebec, despite being common in Ontario. Conclusions In this largest Canadian study, we describe the prevalence, distribution, and clinical characteristics of AD SCA. We found that the distribution of the most common SCA differed in the three provinces studied. This finding reflects the heterogenous nature of the Canadian population.

Spinocerebellar ataxia 27B: A novel, frequent and potentially treatable ataxia

“…45 In Quebec, a frequency of SCA27B as high as 60% has been reported among French-Canadian patients with previously unexplained adult-onset ataxia, making it the most common genetic cause of adult-onset ataxia in this population. 21,46 The observation of a common disease haplotype shared by some French-Canadian patients suggest that the high proportion of SCA27B in this population may correspond to a founder effect in this population known to be enriched for such effects. 47 Similarly, a previous study identified that three Australian patients shared a disease haplotype.…”