Ethnic background and distribution of clinical phenotypes in patients with probable progressive supranuclear palsy

Progressive Supranuclear Palsy (PSP) is a sporadic neurodegenerative disease without a clear geographic prevalence. Cohorts studied in the UK and India showed no higher prevalence of atypical parkinsonism in South Asian patients. We describe the ethnic and racial background of PSP patients in the Greater Toronto Area (GTA), Canada. A prospective observational study of patients with clinically probable PSP evaluated at the dedicated Rossy PSP program. Demographic and clinical data were collected at baseline including PSP phenotype. Results were compared with the latest demographic information from the greater Toronto area. Of the 197 patients screened, 135 had probable PSP and resided within the GTA. The mean age at visit was 71.1 years, disease duration 4.4 years, and disease severity moderate. Compared to our catchment area, there was a higher proportion of patients with a South Asian origin and a lower proportion of patients from East and Southeastern Asia and Africa. A secondary analysis using population census data limited to individuals greater than 65 confirmed the significantly higher representation of South Asians in our clinic but found no differences for other racial and ethnic origins. Evaluation of this Toronto cohort found a greater than expected proportion of affected individuals with South Asian ethnic and racial origin. Despite limitations, our results suggest the possibility of a racial and ethnic predisposition to PSP. Further studies are needed to confirm and to address potential associated risk factors, and genome-environmental interactions. •Progressive supranuclear palsy is an acquired adult-onset neurodegenerative disease with non-geographical predominant distribution.•Previos studies in United Kingdom and India were unable to confirm a higher distribution of PSP in people of indian ethnic and racial background.•We describe the ethnic and racial origin of a cohort in a referral centre in the Great Toronto Area, Ontario, Canada.•We found a greater than expected proportion of PSP patients with South Asian ethnic and racial origin.•Further studies are needed to confirm this finding and to address potential associated risk factors including genome-environmental interactions.