Diabetes and DNA, no strings attached
The scientific community has no clear answer yet as to whether diabetes is hereditary or not. Diabetes has a genetic component, which however is often not enough, on its own, to trigger the onset of the disorder. One of the secrets behind the rare form of diabetes known as MODY (Maturity Onset Diabetes of the Young) is almost entirely hidden within the DNA, while our genetic code has a secondary role in more common forms of diabetes.
Type 2 diabetes and DNA: the study on twins
Various scientific studies have proven that only type 2 diabetes has a hereditary component. To reach this conclusion, research has focused on fraternal twins – whose unique traits have always been an open window on the deepest mysteries of our species and its evolution. Test results have revealed that in monozygotic twins, who share identical DNA, a healthy sibling has more than a 90% chance of developing the disease if the other one is affected.
Type 1 diabetes and DNA: no hereditary link
Scientific studies have highlighted that – unlike type 2 diabetes – there is no automatic genetic cause underlying type 1 diabetes. Indeed, tests on monozygotic twins yield completely different results: there is no transmission between one sibling having type 1 diabetes and the other sibling developing it.
Type 2 diabetes is hereditary in only 25% of cases
These scientific studies, however, have not shown a direct connection between genes and diabetes. Rather, they have revealed a family predisposition in particular for type 2 diabetes. This means the risk of developing diabetes is higher when a first-degree relative is affected by the disease. Most recent data point to the fact that 25% of people with diabetes have inherited type 2 diabetes from their father.
Juvenile diabetes has a genetic origin
Unlike other forms of diabetes, maturity-onset diabetes of the young (MODY) may have hereditary origin. Juvenile diabetes usually occurs in people before 25 years of age. According to research, this form of diabetes is 35-40% hereditary in origin. Women with type 2 diabetes also have a higher chance of having children who will in turn develop the disease, compared to the rest of the population – but the figures are almost irrelevant in absolute terms.
There are 111 hot spots in the DNA for diabetes
A recent research by London’s University College and Imperial College has proven the hereditary nature of type 2 diabetes by comparing the genetic maps of 5,800 affected people and almost 9,700 healthy individuals. The study shows that our genetic code includes 111 “hot spots” linked to a higher risk of developing diabetes, which represent the molecular foundation for our predisposition for the disease.
