The familial nature of multiple sclerosis: age-corrected empiric recurrence risks for children and siblings of patients.

Increasingly, MS patients ask neurologists about the risk that their close relatives will also develop MS. We calculated age-adjusted empiric recurrence risks from data on 815 index cases and over 3,000 of their siblings and children. In general, the risk for these relatives to develop MS is 3 to 5%, which is 30 to 50 times the 0.1% rate for the general population.