While thiopurine S-methyltransferase (TPMT) polymorphisms have not been associated with the risk of thiopurine-induced pancreatitis [56], it has been identified a strong association within the class II HLA region and specifically with the SNP rs2647087 that maps to the HLADQA1* 02:01-HLA-DRB1*07:01 haplotype (odds ratio, OR, 2.59) [62]. Here, TPMT is linked to pancreatitis.