Syndromes Of Extreme Insulin Resistance
Lipodystrophic Syndromes Lipodystrophic syndromes are a heterogeneous group of disorders characterized by the absence of an adipose tissue as well as an extreme insulin-resistant state in most cases. The clinical diagnosis can be made based on the physical exam, certain metabolic abnormalities (fasting insulin level over 30 μU/mL, fasting triglycerides level >200 mg/dL, presence
General clinical manifestations of these syndromes can be classified into two main categories: features related to deficiency of insulin action and those secondary to the effects of high levels of insulin in some relatively insulin-sensitive tissues (Table 17.2).
Significant progress has been made in our understanding of the molecular basis underlying the syndromes of extreme insulin resistance. Some of these diseases are due to genetic defects or mutations in the insulin receptor gene, as seen in the type A syndrome, leprechaunism as well as in the Rabson–Mendenhall syndrome, while circulating antibodies against the
This group of syndromes shares severe insulin resistance and hyperinsulinemia with variable clinical manifestations. Attention has been paid to these rare disorders because they provide insight into several aspects of insulin action at the molecular level and advance our understanding of the more common insulin-resistant disorders, such as polycystic ovarian syndrome and type 2