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Laron-type dwarfism with apparently normal high affinity serum growth hormone-binding protein
C R Buchanan1, H G Maheshwari, M R Norman
1Department of Growth and Development, Institute of Child Health, London, UK.
Clinical Endocrinology
|August 1, 1991
Summary
This study found normal growth hormone-binding protein (GHBP) levels in a family with Laron-type dwarfism, suggesting a novel cause for GH-resistance and low IGF-I. This contrasts with typical Laron dwarfism findings.
Area of Science:
- Endocrinology
- Molecular Biology
- Genetics
Background:
- Normal serum contains a high-affinity growth hormone-binding protein (GHBP), often identical to the GH receptor's extracellular domain.
- GHBP is typically absent in patients with Laron-type dwarfism, a condition characterized by GH-resistance.
Observation:
- An Asian family with three sisters exhibiting Laron-type dwarfism was studied.
- Serum GHBP levels were assessed in affected family members, an unrelated Laron dwarfism patient, and healthy controls.
Findings:
- All affected family members displayed normal GHBP activity, similar in size, levels, and GH affinity to healthy individuals.
- This finding contrasted sharply with the very low GHBP activity observed in the unrelated Laron dwarfism patient.
Implications:
- The affected family may have a novel biochemical defect causing GH-resistance and reduced IGF-I production despite normal GHBP levels.
- This suggests that not all cases of Laron-type dwarfism are solely due to GHBP deficiency.