Given the tremendous geographical differences in the incidence of T1D, one is obviously interested in trying to determine what is causing these patterns No doubt, environmental differences contributes to the variation in T1D incidence rates. However, my work has been to investigate the contribution of genetic differences to the geographical patterns of T1D incidence. Although more than 20 genes have been associated with T1D, those in the HLA region of chromosome 6 confer the strongest risk.