Abstract
The genetic architecture of multiple sclerosis is complicated. Additionally, the disease incidence varies per population or per geographical region. A recent study gives convincing explanations about the north-south incidence gradient of multiple sclerosis in Europe, by analyzing ancient and modern human genomes. Interestingly, the evidence shows that multiple sclerosis associated immunogenetic variants underwent positive selection in Asian and European populations. Lifestyle and pathogen infections probably shaped the overall multiple sclerosis risk. These results complete the findings of previous studies that showed that a high percentage of the autoimmunity associated genetic variants are under selection pressure.