Type A-insulin resistance with lipopexia on extremities: a case report

We present the unusual case of a 17-year-old female with insulin-resistant diabetes, acanthosis nigricans, hirsutism, amenorrhea, dental dysplasia and lipopexia on the extremities. She had been diagnosed as having border line diabetes with hyperinsulinemia at age 12 when she was not obese and diabetes mellitus at age 13. On admission, she was obese and had lipopexia only on the extremities. The presence of hyperinsulinemia and poor response to exogenous insulin suggested severe insulin resistance. Insulin binding to transformed B-lymphoblasts derived from her was extremely low compared to the normal control, showing decreased receptor affinity. Her parents and sister exhibited hypersecretion of insulin in response to a 75 g oral glucose tolerance test. Her mother was diabetic, and her father and sister had border line diabetes, whereas her brother had a normal response. These findings support strongly the diagnosis of a type A syndrome with severe insulin resistance associated with lipopexia on the extremities. A genetic defect in the insulin receptor gene may be responsible.