The genetic contribution to multiple sclerosis. Evidence from North-East England

A study of 206 patients with multiple sclerosis in the north-east of England and their families shows no evidence of monogenic involvement in the disorder. Much more likely is a multifactorial etiology in which the genetic component is polygenic. On this model the heritability is calculated at 52.1% or 40.9% if age variation in incidence is allowed for. The genetic component is present but no more then moderate in extent.