IgM antibodies against GnRH1 have been found in patients with diabetes mellitus, gastrointestinal dysmotility, IBS, posterior laryngitis, and primary Sjögren’s syndrome, independent of treatment with GnRH analogs, in contrast to patients with celiac disease, inflammatory bowel disease, microscopic colitis, and sclerodermia, who express antibodies to the same extent as controls (39–45). This evidence concerns the gene GNRH1 and microscopic colitis.