[Laron type dwarfism. Study of GH binding protein in 3 cases]

Laron's type dwarfism (LTD) has clinical features very close to those of congenital isolated growth hormone (GH) deficiency, contrasting with high plasma levels of GH and a complete lack of growth improvement during treatment trials with exogenous GH. Three new cases are presented here. The plasma GH-binding protein (GHBP), which has been recently isolated and identified as similar to the extracellular part of the liver-cells receptor to GH, is lacking in two of the three patients and subnormal in their heterozygous parents, these data suggesting a defect of the GH receptor or of its extracellular part. In contrast, the third patient and her parents had normal plasma levels of GHBP, suggesting that the clinically and biologically obvious lack of receptivity to GH is either at the post-receptor level or limited to the intracellular part of the receptor. These data contribute to demonstrate that there are at least two different genetic defects leading to clinical LTD.