Familial insulin resistance and acanthosis nigricans.

Insulin resistance exists in 0.1% of diabetics having insulin treatment. In addition to diabetics, insulin resistance can also be seen in association with acanthosis nigricans. Both conditions become a syndrome that may happen in a family. This is a report of two siblings, a brother and a sister, 14 and 10 years of age, whose parents are cousins, who suffered from diabetes mellitus, acanthosis nigricans, and growth retardation. The insulin therapy until 54 units per day given to the boy and 174 units per day to the girl, did not give response to the plasma glucose level. Plasma C-peptide and prolactin values of the girl were normal. The plasma fasting insulin level of both was high. Measurement of insulin binding to erythrocytes and monocytes was not performed. The GTT observations of their parents did not represent glucose intolerance.