Abstract
The case of a 14-year-old female with acanthosis nigricans, hyperinsulinemia and mild glucose intolerance is reported. Her mother and brother also had hyperinsulinemia and glucose intolerance. The patient's fasting plasma insulin level was 160 μU/ml by radioimmuno assay, 158μU/ml by radioreceptor assay, and a decreased sensitivity to exogenous insulin was observed. The plasma levels of cortisol, glucagon and growth hormone were normal, and neither anti-insulin nor anti-insulin receptor antibody was detected in her plasma. The plasma proinsulin level was less than 10 % of the total insulin immunoreactivities, and the biological activity of her plasma insulin was normal. Scatchard analysis revealed a decreased insulin binding to the patient's erythrocytes due to a decrease in receptor capacity.
These findings suggest that the glucose intolerance in the patient was caused by a congenital insulin receptor defect corresponding to type A on the classification of Kahn et al.
