Síndrome de insulinorresistencia severa tipo A debido a mutación del gen del receptor de insulina

Insulin resistance syndromes without lipodystrophy are an infrequent and heteroge-neous group of disorders with variable clinical phenotypes, associated with hyperglycemia and hyperinsulinemia. The three conditions related to mutations in the insulin receptor gene areleprechaunism or Donohue syndrome, Rabson-Mendenhall syndrome, and Type A syndrome. A case is presented on a patient diagnosed with type A insulin resistance, defined by thetriad of extreme insulin resistance, acanthosis nigricans, and hyperandrogenism, carrying aheterozygous mutation in exon 19 of the insulin receptor gene coding for its tyrosine kinasedomain that is crucial for the catalytic activity of the receptor. The molecular basis of the syndrome is reviewed, focusing on the structure-function rela-tionships of the insulin receptor, knowing that the criteria for survival are linked to residualinsulin receptor function. It is also pointed out that, although type A insulin resistance appearsto represent a somewhat less severe condition, these patients have a high morbidity and their treatment is still unsatisfactory.