XPR1 and primary biliary cholangitis: WES revealed a total of 22 different rare genetic variants in known PBC disease genes [SLC20A2, n = 7; PDGFB, n = 3; PDGFRB, n = 2; XPR1, n = 3; MYORG, n = 6 and JAM2, n = 1; (Supplementary Table 2)] in 28 individuals.