To date, mutations of the insulin receptor remain the only well-established causes of severe
insulin resistance. There is a broad correlation between the extent of impairment of signal
tranduction seen when the mutant receptors are expresed in vitro with the severity of the
clinical phenotype. Thus leprechaunism, Rabson—Mendenhall syndrome and Type A
insulin resistance appear to represent points on a continuum of severity of receptor
dysfunction, rather than completely distinct syndromes. In other syndromes of insulin …