Diabetes has obvious genetic susceptibility (especially the most common type 2 diabetes in clinic). Family studies have found that the prevalence of diabetes in people with positive family history is significantly higher than that in people with negative family history. Children whose parents have diabetes are 15 ~ 20 times more likely to have diabetes than ordinary people.
Heredity plays a role in the pathogenesis of 1 diabetes. Long-term follow-up of monozygotic twins with 1 type diabetes shows that the coincidence rate of twins with diabetes can reach 50%. However, the vertical transmission rate from parents to children is very low. For example, if one parent has 1 diabetes, the risk rate of their children's illness is only 2% ~ 5%.
In the etiology of type 2 diabetes, genetic factors are more important than 1 diabetes. The coincidence rate of identical twins with type 2 diabetes is 90%, and the risk rate of their children with one parent with type 2 diabetes is 5% ~ 10%. Among the children of both parents, 5% have diabetes and 12% have IGT. The genetic causes of most type 2 diabetes are still unclear.
Besides, my friend's grandmother has type 2 diabetes, but her six children and their descendants don't have diabetes, at least not yet.