Type 1 Diabetes and Multiple Sclerosis

Last year, Marrosu et al. (1) reported an increased prevalence of type 1 diabetes among Sardinian individuals with multiple sclerosis and their first-degree relatives. The study was accompanied by a commentary (2) indicating that these autoimmune disorders were “an unlikely alliance” because the HLA haplotype that increases risk for multiple sclerosis (DRB1\*15-DQA1\*0102-DQB1*0602) protects against type 1 diabetes. To the authors’ knowledge, there have been no published studies of an increased risk of multiple sclerosis for individuals with type 1 diabetes or their families. Could the association between type 1 diabetes and multiple sclerosis be unique to Sardinia, where the rates of these two disorders are among the highest in the …