Since its creation in 1980, the Multiple Sclerosis Clinic at the Univ of British Columbia has actively followed over 2,500 patients from the Canadian province of British Columbia (BC) who have Clinically Definite Multiple Sclerosis (MS).
These patients include 2,496 European Caucasians from a BC population of 3,858,505 (prevalence 64.7/100,000) in contrast with 92 patients of other Ethnic origin (prevalence
14.6/100,000). Prevalence was higher in South Asians (15.7 from a population of 114,355) than in East Asians (6.25 from 287,845).
Among individuals with Native Ancestry, MS was not rare when there was also European Ancestry (46 cases from a population of 94,615), but MS was not encountered in pure-blooded Natives (0 cases from 74,420 individuals).
In contrast, among 5 patients with HTLV-I-Associated Myelopathy (HAM), 4 (from a population of 74,420) were of single Native Ancestry and only 1 (from a population of 94,615) was of multiple ancestry, including Native Ancestry.
HAM was not found among Caucasians. This preliminary account clearly establishes that HAM is linked to Native Ancestry and that MS is linked to Caucasian Ancestry.