MEFV Gene-Related Enterocolitis Account for Some Cases Diagnosed as Inflammatory Bowel Disease Unclassified

Background and Aims: Familial mediterranean fever (FMF), an autoinflammatory disease, is characterized by periodic fever and serositis. An MEFV gene mutation has been identified as the cause of FMF. Recently, patients with MEFV gene mutations and chronic gastrointestinal mucosal inflammation mimicking inflammatory bowel disease (IBD) have been reported. In this retrospective study, we analyzed the clinical characteristics of patients with IBD unclassified (IBDU) with MEFV gene mutations. Methods: MEFV gene analysis was performed on 8 patients with IBDU among 710 patients with IBD who had been treated at Kyorin University Hospital from April 2016 to December 2018. Clinical manifestations, endoscopic findings, and serological markers were also analyzed. Results: The average of the 8 patients with IBDU (3 men, 5 women) was 32.7 ± 6.4 years (range 26–76 years). Their symptoms comprised diarrhea (n = 8, 100%), hematochezia (n = 3, 37.5%), abdominal pain (n = 3, 37.5%), high fever (n = 2, 16.5%), and other periodic symptoms (n = 2, 16.5%). MEFV gene mutation was confirmed in 4/8 of these patients. Colonoscopy showed various mucosal lesions, rectal sparing, right side dominant colitis, pseudopolyposis, and granular protrusions. Colchicine was administered to 5 of the 8 patients (4 with and 1 without MEFV mutation) who were resistant to conventional treatment for ulcerative colitis. Clinical and endoscopic improvement was observed in all of 5 patients treated with colchicine. Conclusions: Some patients diagnosed as having IBDU have enterocolitis related to MEFV gene mutation and respond to colchicine therapy.