Genetics may play a role in the development of diabetes for many patients, along with environment and behavior. Scientists have linked several specific genes to the various forms of diabetes.

The risks of developing type 1 diabetes, an autoimmune disease, are greater when a parent also has the disease. This factor indicates a probable genetic factor. A single gene that is responsible for type 1 diabetes has not been identified. However, 19 sections of the human genome (complete genetic material) are believed to be involved.

Type 2 diabetes is also highly complex developmentally. It is the most common type of the disease and has the clearest association with genetic inheritance. It may involve multiple genes that cause insulin resistance or that result in loss of insulin being produced by the pancreas. Researchers have found that exercise and weight loss may often prevent type 2 diabetes in people with genetic risk factors.

For other types of diabetes, such as maturity-onset diabetes of the young (MODY), a genetic link is clearly established. There are six types of MODY, each associated with a single genetic defect inherited from a parent. Other diabetic conditions with identified genetic causes include Wolfram syndrome, type A insulin resistance and Rabson-Mendenhall syndrome, which also causes insulin resistance.