Epidemiologic studies of multiple sclerosis: a review.

There is evidence for genetic factors in multiple sclerosis (MS). The evidence come from epidemiologic studies, racial predilection, risk in family members (sibs, half sibs, adoptees) and twins studies. MS is not a Mendelian inherited disease; only the susceptibility to the disease is inherited, the risk of MS being also related to an environmental factor. Many candidate genes were screened, and there are four research groups trying to study the whole genome. MS seem to be an oligo- or multigenic disorder with an apparently similar phenotype for the different genes involved.