HLA-C and hereditary disease: The remaining sections review: (a) technical advancements in the definition of HLA, complement and other MHC-associated gene alleles as well as advancements in our understanding of the core MHC genomic architecture; (b) CEH extension to most of the remaining MHC region; (c) identification of ethnic differences in MHC CEH distributions; (d) insights into MHC-associated genetic diseases achieved through the knowledge of and use of pedigree-based MHC haplotypes; and (e) the development of new genetic disease models as a consequence of considering the existence of CEHs.