Is type 2 diabetes hereditary?

Genetics appears to play a role in how type 2 diabetes develops. Like type 1 diabetes, type 2 diabetes also appears to run in families, and it is most likely due to the inheritance of certain genes. The link to genetics seems even stronger in type 2 diabetes than in type 1 diabetes. If a person with type 1 diabetes has an identical twin, there is a 25 to 50 percent chance that the twin will develop diabetes. But if a person with type 2 diabetes has an identical twin, there is a 60 to 75 percent chance that the person will develop diabetes.

More evidence for the role of genes in type 2 diabetes comes from studying certain ethnic groups. Compared with Caucasians, African Americans, Asian Americans, Hispanic Americans (except Cuban Americans), and Native Americans all get type 2 diabetes more often. Native Americans have the highest rate of type 2 diabetes in the world. Hispanic groups, such as Mexican Americans, that share genes with Native American groups (where there has been cultural mixing) have a higher rate of type 2 diabetes than Hispanic groups, such as Cuban Americans, where less intercultural contact has occurred.
“Both type 1 and type 2 diabetes have a hereditary component,” says Peter Butler, MD, chief of the Division of Endocrinology, Diabetes and Hypertension, and director of the Larry L. Hillblom Islet Research Center at UCLA. "Previously, many people with type 2 diabetes felt guilty about their disease because they believed they caused it by the way they lived their lives. But while many of us eat too much or don’t exercise enough, it is only those with a genetic predisposition who may develop the disease. In these individuals, diabetes develops because the cells that make insulin in the islets are gradually lost."

And while most people who have a genetic predisposition won’t ever develop diabetes, scientists are working to understand why it appears in some individuals but not in others.

Dr. Butler emphasizes that healthy lifestyle choices -- particularly taking steps to curb obesity -- remain important in controlling the disease. "If you become obese, your pancreas has to work harder to produce insulin," says Dr. Butler, "and if you’re among the 20% of people who have inherited the genes that increase your risk for diabetes, you are at relatively high risk of developing the disease."

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.