BRCA1 and primary biliary cholangitis: In our study for example, BRCA1 mutation carriers were more often aged under 35 years at PBC diagnosis than BRCA2 mutation carriers (29.8% vs. 16.7% respectively), more often had grade III PBC (83.7% vs. 56.5%), and more often had ER-negative PBC (78.2% vs. 24.7%).