[Extreme insulin resistance type A].

Extreme insulin resistance Type A is defined as the syndrome with decreased insulin sensitivity associated with decreased insulin binding to the receptor. The patients usually present with acanthosis nigricans, hirsutism and polycystic ovary. The mechanism for deceased insulin binding includes decreased affinity of insulin receptors, abnormal biosynthesis of the receptor i.e. defect of processing from proreceptor to mature receptor and increased degradation of the proreceptors. The same mutation in the insulin receptor does not always necessarily show the same phenotypes of skin lesion or the same glucose intolerance.