[Influence of genetic factors on multiple sclerosis].

Epidemiological studies have provided evidence for a genetic contribution to the susceptibility of multiple sclerosis (MS). One in six patients has at least one affected family member. The concordance rate is approximately 25% in monozygotic twins, and 3% in siblings, however the prevalence in adopted siblings is similar to the general population (0.1%) MS is thought to be a T cell-mediated autoimmune disease and therefore genes controlling the immune response have been studied intensively as potential susceptibility factors. The best documented association was found for genes of the human-leukocyte antigen complex. Other possible susceptibility genes may reside in the regions of the T cell receptors and the tumour necrosis factors. So far it is clear, that MS is a multifactorial disease in which several genes must be involved. Population genetics and molecular biology will help to characterise further these susceptibility factors.