Before the advent of diagnostic criteria for multiple sclerosis (MS), it was reported that the prevalence of MS in Mexico was "one of the lowest in the world" (1.6/100,000).(1) The notion that MS was a rare neurologic disease among those living in the tropics of the Americas and Southern latitudes was widely accepted. The geopolitical boundaries of the region identified as Latin America (LA) extend from the southern border of United States with Mexico (32° North latitude) to the Argentinian and Chilean Patagonia in South America (56° South latitude). The largest Spanish-speaking island countries in the Caribbean-Cuba, Dominican Republic, and Puerto Rico-are also traditionally considered part of LA. The continental mass includes 17 countries with a population of more than 550 million. Due to centuries of racial intermixing, it is a heterogeneous and genetically complex population. The blended cultures of native Amerindians with white Caucasian Europeans and black Africans has resulted in the predominant ethnic Latin American Mestizo. The influence of African genetics is notable in many areas of the subcontinent and the Caribbean. A common observation across LA is the absence of identification of MS in non-mixed Amerindians(2); the reason for this phenomenon is unclear.