PDC and primary biliary cholangitis: GI, gastrointestinal; SSc, systemic sclerosis; anti-M3R, anti-muscarinic acetylcholine receptor type 3 antibody; anti-RNPC3, anti-RNA-binding region-containing protein 3 antibody; anti-U1RNP, anti-U1 small nuclear ribonucleoprotein antibody; anti-gephyrin, anti-gephyrin antibody; AMA-M2, anti-mitochondrial antibody type M2; anti-CDT, anti-cytolethal distending toxin antibody; PDC-E2, pyruvate dehydrogenase complex E2 subunit; PBC, primary biliary cholangitis.