MHC encodes the human leukocyte antigens (HLA) genes and many other genes with important roles in the regulation of the immune system as well as in some fundamental cellular processes and known to be associated with more than 100 diseases, including common ones such as diabetes, rheumatoid arthritis, psoriasis, asthma, and various autoimmune disorders67. The gene discussed is HLA-C; the disease is asthma.