HLA-A [SEP] chromosome
arm of chromosome 6 and encodes the larger, α-chain, constituent of HLA-A. Variation of HLA-A α-chain is key to HLA function. This variation promotes genetic diversity in the population. Since each HLA has a different affinity for peptides of certain structures, greater variety of HLAs means greater variety of antigens to be 'presented' on the cell surface, enhancing the likelihood that a subset of the population will be resistant to a given foreign invader. This decreases the likelihood that a single pathogen has
, while HLA-A11 is associated with the disease in Koreans. Several genes within this region of class I HLA are believed to be responsible for DPB, by allowing increased susceptibility to the disease. The common genetic background and similarities in the HLA profile of affected Japanese and Korean individuals were considered in the search for a DPB gene. It was suggested that a mutation of a suspected disease-susceptibility gene located somewhere between HLA-B and HLA-A had occurred on an ancestral chromosome carrying both HLA-B54 and HLA