Genetics of Diabetes
You’ve probably wondered how you developed diabetes. You may worry that your children will develop it too.
Unlike some traits, diabetes does not seem to be inherited in a simple pattern. Yet clearly, some people are born more likely to develop diabetes than others.
What Leads to Diabetes?
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 1 Diabetes
In most cases of type 1 diabetes, people need to inherit risk factors from both parents. We think these factors must be more common in whites because whites have the highest rate of type 1 diabetes.
Because most people who are at risk do not get diabetes, researchers want to find out what the environmental triggers are.
One trigger might be related to cold weather. Type 1 diabetes develops more often in winter than summer and is more common in places with cold climates.
Another trigger might be viruses. Perhaps a virus that has only mild effects on most people triggers type 1 diabetes in others.
Early diet may also play a role. Type 1 diabetes is less common in people who were breastfed and in those who first ate solid foods at later ages.
In many people, the development of type 1 diabetes seems to take many years. In experiments that followed relatives of people with type 1 diabetes, researchers found that most of those who later got diabetes had certain autoantibodies in their blood for years before.
(Antibodies are proteins that destroy bacteria or viruses. Autoantibodies are antibodies ‘gone bad,’ which attack the body’s own tissues.)