What is Monogenic Diabetes? How to Diagnose Monogenic Diabetes? Genetic Testing. The most common types of diabetes, Type 1 and Type 2 are “polygenic”, meaning developing from multiple genes. Polygenic forms of diabetes are often genetically inherited and run in families. In most cases of Type 2 diabetes, overeating, lack of physical activity and a poor diet are recognized causes, but such patients also have a strong family history of Type 2 diabetes, suggesting a genetic contribution to the disease as well.