Abstract
Diabetes mellitus is largely determined by genetic factors but environmental factors are necessary to convert genetic susceptibility into overt disease. Studies of twins show that the genetic impact in non-insulin-dependent diabetes mellitus is stronger than in insulin-dependent diabetes mellitus. The genetic factors involved in non-insulindependent diabetes mellitus are not known and the outcome of molecular genetic research has so far been disappointing. The major genetic susceptibility to insulindependent diabetes mellitus is conferred by genes in the HLA region on chromosome 6. Despite many advances in molecular genetics in insulindependent diabetes mellitus the serologically detectable HLA antigens and haplotypes are still the best available markers. This review describes the important developments in immunogenetics in insulindependent diabetes mellitus and summarises the main findings from earlier studies. Genetically the potential for primary prevention of insulin-dependent diabetes mellitus already exists and will become a reality as soon as the environmental determinants are identified. A wide application of immunogenetic methods will be needed in the prevention of insulin-dependent diabetes mellitus.