TGM2 and primary biliary cholangitis: Similar associations have been reported for autoimmune cholestatic diseases, with CD being prevalent in 3.5% of patients with autoimmune cholestasis, including primary biliary cirrhosis, autoimmune cholangitis, and primary sclerosing cholangitis—especially the first—with immunoglobulin A endomysial and human tissue transglutaminase (anti-tTG) usually being positive [89].