Multiple Sclerosis in Latin Americans: Genetic Aspects

Latin Americans (LA) are a heterogeneous, multiethnic group of individuals who inhabit the continental countries in Latin America (LATAM), Caribbean islands and constitute the largest ethnic minority in the USA. Commonly used terminology and ethno racial classifications to define these groups may not be accurate. Risk for multiple sclerosis (MS) among LA is generally low to medium but frequencies are increasing in the American hemisphere. Genome-Wide Association Studies (GWAS) in LA show diverse variants and genetic proportions among Mestizos, the most representative ethnic population, who themselves are the product of centuries of interracial mixing between Native Americans (or Amerindians), White Caucasian Europeans, and Black Africans. Genetic distribution diversity appears to be related to migratory and historical and socio-political factors in LATAM. Epidemiologic studies show an extremely low prevalence of MS among non-mixed Amerindians; this has been attributed to protective ancestral Asian genetics and possibly, environmental factors. Mestizos and biracial LA of African ancestry have more susceptibility to MS apparently due to the historical introduction of the European HLA-DRB1*1501 gene. Contribution from HLA typing, GWAS, and ancestry informative markers (AIMs) has been determinant in the current LA genetic understanding but more regional studies are needed. The relationship between genetics and disease regional distribution is emphasized.