HLA-C and inflammatory bowel disease: The relatively limited contribution of the genetic polymorphisms across the MHC to heritability in IBD was consistent with prior GWAS results, as the MHC SNP (rs1626392, P<2.27 × 10−7) most significantly associated with CD did not reach genome-wide significance, defined as P<5 × 10−8 (Supplementary Table 8).