Immunogenetics is a branch of medical genetics that explores the relationship between the immune system and genetics. Autoimmune diseases such as type 1 diabetics are complex genetic traits which results from defects in immune system. Identification of genes defining the immune defects may identify new target genes for therapeutic approach. Alternatively genetic variation can also help to define the immunological pathway leading to disease. The term Immunogenetics comprises all the processes of organisms, which are on the one hand, controlled and influenced by the genes of the organism and are on the other hand significant with the regard to the immunological defense reaction of the organism.