High frequency of psoriasis in relatives is associated with early onset in an Italian multiple sclerosis cohort

Objectives - An exploratory study has been carried out to assess the association of autoimmune diseases in multiple sclerosis (MS) families with clinical features and disability of MS patients. Material and methods - Age at onset, symptoms and signs at onset, and disability were assessed in 177 patients with definite MS and 178 age- and sex-matched control patients with autoimmune diseases (78 with endocrine and 100 with rheumatological diseases) and correlated with the most frequent autoimmune diseases recorded in the families. Results - Psoriasis was found in 30 relatives of 177 (16.9%) MS patients, thyroid disorders in 17 (9.6%) and allergies in 17 (9.6%). In the control group, psoriasis was found in 22 relatives of 178 (12%) patients, thyroid diseases in 19 (10.7%) and allergies in seven (3.9%). Of the 30 relatives with psoriasis in the MS group, 16 (53.3%) were fathers (P < 0.0001). There was a significant association of high frequency of family psoriasis with early age of MS onset (P = 0.025) but not with onset of symptoms or severe disability. Conclusion - In this Italian MS cohort, a subgroup of patients with a first- or second-degree relative with psoriasis had early onset of MS.