Laron syndrome due to a post-receptor defect: response to IGF-I treatment

Isr J Med Sci. 1993 Dec;29(12):757-63.


Three siblings with Laron syndrome (LS) and normal serum growth hormone binding protein (GHBP) are described. Basal serum levels of hGH were high and IGF-1 low, and in contradistinction to the classical form of the disease serum GHBP and IGFBP-3 were normal in these patients. After 7 days of human growth hormone administration serum IGFBP-3 levels as well as the number of red blood cell IGF receptor sites increased. After short- and long-term IGF-1 administration the IGF-1 receptor binding capacity as well as the number of IGF receptor sites decreased to levels found in control subjects. One year treatment with IGF-1 increased the growth velocity by 47-96% in the two older children. It is concluded that the findings described are compatible with a normal GH receptor and normal signal transmission for IGFBP-3 synthesis but a defect exists in the post-GH receptor mechanism for the generation of IGF-1. This is the first description of this type of defect leading to a variant of Laron syndrome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Carrier Proteins / blood
  • Child
  • Child, Preschool
  • Dwarfism, Pituitary / drug therapy*
  • Dwarfism, Pituitary / genetics*
  • Dwarfism, Pituitary / metabolism
  • Female
  • Humans
  • Infant
  • Insulin-Like Growth Factor I / metabolism
  • Insulin-Like Growth Factor I / therapeutic use*
  • Male
  • Receptors, Somatotropin / metabolism*
  • Recombinant Proteins / therapeutic use
  • Syndrome


  • Carrier Proteins
  • Receptors, Somatotropin
  • Recombinant Proteins
  • Insulin-Like Growth Factor I