A reduced number of insulin receptors in patients with Prader-Willi syndrome.

The Prader-Willi syndrome is among other features characterized by obesity and a high prevalence of glucose intolerance. The fasting plasma insulin concentration and the insulin response to glucose are often increased, indicating some insulin resistance in this disease. To investigate whether this could be due to an insulin receptor defect 7 patients with Prader-Willi syndrome, 10 normal weight subjects and 8 obese subjects were tested for the binding of [125I]insulin to monocytes. Monocytes from patients with Prader-Willi syndrome bound significantly less insulin than cells from normal subjects (P less than 0.01). However, no difference was found between Prader-Willi patients and the obese controls (P greater than 0.1). It is concluded that the insulin resistance found in Prader-Willi patients, similar to that found in obese subjects, in part, may be explained by an insulin receptor defect on target cells for insulin action.