SCAs are a group of AD progressive neurodegenerative disorders, and are seen in a variety of ethnic backgrounds. The only previous Canadian study of SCAs was from Alberta Canada and included 69 patients with the most prevalent SCAs being SCA3 (23.8%), SCA2 (14.3%), and SCA6 (9.5%). 

We had a total of 203 patients. The majority of our patients were of Caucasian (47.8%), Asian (28.6%), and Portuguese (15.3%) ethnic backgrounds. We found that the distribution of the most common SCA differed when comparing province to province. The most prevalent SCA diagnoses in Ontario were SCA3 (49%), followed by SCA1 (14%), then SCA 2 (13%). In contrast, the most prevalent SCA diagnoses in Alberta were SCA2 (26%), SCA3 (20%), and SCA 8 (13%). Similar to Alberta, SCA2 was the most prevalent SCA subtype in Quebec (47%), followed by SCA3 (17%). SCA6 was the third most prevalent SCA subtype in Quebec (14%), which was not seen as commonly in other provinces. Despite being among the most common SCA subtypes found in Ontario, SCA1 was uncommonly seen in both Alberta and Quebec.

The most prevalent AD SCAs in Canada is SCA3 followed by SCA2, SCA1, SCA6, SCA8, in this order. We found that the distribution of the most common SCAs differed when comparing provinces. This finding reflects the heterogenous nature of the Canadian population. SCA3 is the most common SCA subtype in Ontario, partially reflecting the large Portuguese community within Ontario.