HLA-DRB1 and type 1 diabetes mellitus: As for primary biliary cholangitis (PBC), approx. 25% of PSC patients present with other autoimmune diseases, such as type I diabetes mellitus (T1DM), Hashimoto’s thyroiditis, celiac disease, psoriasis, and rheumatoid arthritis (Figure 1), and it is correlated to the HLA-DRB1*03031 haplotype and presents perinuclear anti-neutrophil cytoplasmic antibodies (pANCAs), considered as a prognostic marker for the disease [10].