XPR1 and primary biliary cholangitis: Previous studies have reported <i>SLC20A2</i>, <i>PDGFB</i>, <i>PDGFRB</i>, <i>XPR1</i>, <i>MYORG</i>, <i>JAM2</i>, <i>CMPK2</i>, and <i>NAA60</i> as causative genes for familial PBC.