No excess of autoimmune diseases in multiple sclerosis families from the Netherlands
Multiple sclerosis (MS) is a complex inflammatory disease that affects the central nervous system (CNS), including the brain, the spinal cord and optic nerves. MS is considered an autoimmune disease because of the involvement of the T and B cells in its pathophysiology, and in the Northern Europeans, MS has been associated with an extended MHC haplotype containing the HLA‐DRB1*1501 locus.2 Network‐based analysis of genome‐wide association studies has shown a significant sharing of genetic loci between MS and other autoimmune diseases such as type 1 diabetes, rheumatoid arthritis and Crohn's disease.3 With a cross‐phenotype meta‐analysis, Cotsapas et al have shown that nearly 44% of immune disease‐risk single‐nucleotide polymorphisms (SNPs) are associated to multiple, but not all AIDs.4 Co‐occurrence of several AIDs in one patient is therefore not surprising. Some studies suggest that first‐degree relatives of probands with MS could be at a greater risk of autoimmune diseases other than MS,5 while some studies do not support these findings.11 To what extent MS and other AIDs co‐occur in MS multiplex families with two or more affected individuals with MS also remains controversial.5
The aim of our study was to describe coexisting autoimmune diseases in patients with MS and their first‐degree relatives from the Dutch MS multiplex families and compare them to spousal controls.