No excess of autoimmune diseases in multiple sclerosis families from the Netherlands.

OBJECTIVES: Autoimmune diseases (AIDs) cluster in families; however, to what extent AIDs co-occur in MS multiplex families with two or more affected individuals is still controversial. The study aimed to evaluate coexisting AIDs in this type of families from the Netherlands.

MATERIALS AND METHODS: A total of 155 MS multiplex families (155 MS probands, 959 first-degree relatives and 212 spouses) were characterized for a history of 11 AIDs by means of a self-administered questionnaire.

RESULTS: In 43.2% of MS multiplex families, at least one AID was present in the first-degree relatives. Overall, the frequency of AIDs was not significantly different between patients with MS (11%), their first-degree family members (11%) and controls (5.2%). After correction for age at inclusion and gender, the odds ratios (OR) for AIDs were not significant for patients with MS (OR = 1.8 [0.77-4.34], P = .17) and first-degree family members (OR = 2.0 [0.98-4.10], P = .06) when both compared to spouses. The frequency of AIDs in mothers did not differ from that in fathers after correction for sex bias (19% vs 8%, P = .51). A presence of AID was more often reported in maternal than paternal second-degree relatives (23% vs 10%, P = .0020).

CONCLUSION: Although nearly half of the Dutch MS multiplex families reported an AID, no excess of AIDs was present in patients with MS from multiplex families or their first-degree family members compared to the spouses.