Genetic causes of diabetes mellitus type 1

At least 20 different chromosomal regions have been linked to type 1 diabetes (T1D) susceptibility in humans, using genome screening, candidate gene testing, and studies of human homologues of mouse susceptibility genes.

Responsible genes
The largest contribution to the pathogenesis of Type 1 Diabetes comes from a single locus called IDDM1 comes from several genes located in the Major histocompatibility complex on the 6p21.3 chromosome. This is believed to be responsible for at least 40% of the disease's familial aggreagation.

Additionally, nearly 30% of Type I Diabetes patients are heterozygous for several HLA-DQ2 (specifically HLA-DQ2/DQ8) alleles. However, the HLA-DQ6 allele (HLA-DQA1*0102–DQB1*0602), if dominant, is responsible for partially preventing an organism from developing the disease. Therefore, these genetic features can be used to determine a patient's relative risk of developing the disease.

Further discussion and research of the functional genomics of the pathogenesis of Type 1 Diabetes will be necessary in future studies in this field.