A review. Diabetic microangiopathy is one of the most serious complications of diabetes mellitus. Some patients have a long course of disease and poor control of blood glucose, but they do not have diabetic microangiopathy or only show slight pathol. changes after a long term follow-up. Other patients only have a short term disease and well control of blood glucose, but they develop serious proliferative diabetic microangiopathy. The patients have a pos. family history. This phenomenon may relate to various genetic liabilities.