Growth hormone (gh) insensitivity due to primary gh receptor deficiency

The clinical phenotype of GH deficiency (GHD), but with elevated serum levels of GH, was originally described by Laron et al. (1) in 1966. Recognition that this syndrome was the consequence of GHI due to an abnormality of the GH receptor (GHR) evolved from studies pursued over the subsequent 25 yr (Table 1). Laron syndrome represents the primary hereditary form of GHI, but only part of the spectrum of GHI. A recent consensus document has proposed a classification for the various syndromes of GHI (see Table 2) (34). This review will focus on the clinical, biochemical, and molecular characteristics of GHR deficiency¹ (GHRD) as the prototype of GHI. This condition, although rare, with only about 200 affected individuals worldwide, has been the subject of intense study over the last 5 yr, providing insights into the molecular, physiological, and clinical aspects of growth. The ability to document the effects of administered insulin-like growth factor I (IGF-I) synthesized by recombinant DNA techniques has made study of GHRD exceptionally rewarding.