Conjugal multiple sclerosis in Isfahan, Iran: a population-based study.

Conjugal multiple sclerosis (MS) is a rare form of MS in which both spouses are affected, and at least one is affected after marriage. Among 1606 definite MS patients, 1076 were in marital relationship, among whom we identified six conjugal pairs, giving the conjugal rate of 0.5%. This rate is 12.5 times higher than the estimated risk of MS for the general population (0.04%). The observed conjugal rate suggests an increased risk of developing MS for MS patients' spouses, this could be due to transmission or, more likely, to the same environmental factors shared in adult life.