Is there a genetic link in type 2 diabetes?

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.