Genetics and multiple sclerosis: an overview.

There is evidence to support the view that multiple sclerosis is a complex trait determined by both genetic and environmental factors. The genetic component is reflected in the higher rate of concordance in monozygotic versus dizygotic twins and in familial recurrence risk data. These data fit best with oligogenic hypotheses encompassing epistatic interactions. However, confirmation will require comprehensive linkage studies using techniques that can rapidly screen the entire genome. The number of families required to demonstrate the effects of a locus such as the major histocompatibility complex is very large.