Unlike some traits, diabetes does not seem to be inherited in a simple pattern. Yet clearly, some people are born more likely to get diabetes than others.
Type 1 and type 2 diabetes have different causes. Yet two factors are important in both. You inherit a predisposition to the disease then something in your environment triggers it.
Genes alone are not enough. One proof of this is identical twins. Identical twins have identical genes. Yet when one twin has type 1 diabetes, the other gets the disease at most only half the time. When one twin has type 2 diabetes, the other's risk is at most 3 in 4.
Type 2 diabetes has a stronger link to family history and lineage than type 1, although it too depends on environmental factors. Studies of twins have shown that genetics play a very strong role in the development of type 2 diabetes. Lifestyle also influences the development of type 2 diabetes. Obesity tends to run in families, and families tend to have similar eating and exercise habits.
If you have a family history of type 2 diabetes, it may be difficult to figure out whether your diabetes is due to lifestyle factors or genetic susceptibility. Most likely it is due to both. However, don’t lose heart. Studies show that it is possible to delay or prevent type 2 diabetes by exercising and losing weight.
Have you recently been diagnosed with type 2 diabetes? Join our free Living With Type 2 Diabetes program and the information and support you need to live well with diabetes.
More Information on Genetics
If you would like to learn more about the genetics of all forms of diabetes, the National Institutes of Health has recently published The Genetic Landscape of Diabetes. This free online book provides an overview of the current knowledge about the genetics of type 1 and type 2 diabetes, as well other less common forms of diabetes. The book is written for health professionals and for people with diabetes interested in learning more about the disease.