Laron syndrome due to a post-receptor defect: response to IGF-I treatment.
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.
Laron
Z
Z
Endocrinology and Diabetes Research Unit, Children's Medical Center of Israel, Petah Tikva.
Klinger
B
B
Eshet
R
R
Kaneti
H
H
Karasik
A
A
Silbergeld
A
A
D000328:Adult; D002352:Carrier Proteins / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004393:Dwarfism, Pituitary / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000627:therapeutic use*; D008297:Male; D011986:Receptors, Somatotropin / Q000378:metabolism*; D011994:Recombinant Proteins / Q000627:therapeutic use; D013577:Syndrome
D002352:Carrier Proteins; D011986:Receptors, Somatotropin; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I