Laron syndrome
| Laron syndrome | |
|---|---|
| Specialty | Endocrinology  |
Laron syndrome, or Laron-type dwarfism, is an autosomal recessive disorder characterized by an insensitivity to growth hormone (GH), caused by a variant of the growth hormone receptor. It causes short stature.
Eponym
It is named after Zvi Laron, the Israeli researcher who, with A. Pertzelan and S. Mannheimer, first reported the condition in 1966,[1][2] based upon observations which began in 1958.[3]
Resistance to GH was first reported by Laron in 1966. Since then, severe resistance to GH, characterized by grossly impaired growth despite normal levels of GH in serum, has been termed Laron syndrome.
Pathophysiology
Molecular genetic investigations have shown that this disorder is mainly associated with mutations in the gene for the GH receptor. These can result in defective hormone binding to the ectodomain or reduced efficiency of dimerization of the receptor after hormone occupancy. There are exceptionally low levels of insulin growth factor (IGF-1) and its principal carrier protein, insulin-like growth factor binding protein 3. This deficiency in IGF-1 is believed to provide the Ecuadorian Laron's with a full immunity to cancer.[4]
A related condition involving postreceptor insensitivity to growth hormone has been associated with STAT5B.[5]
Clinical characteristics
The principal feature of Laron syndrome is abnormally short stature (dwarfism). Physical symptoms include: prominent forehead, depressed nasal bridge, under-development of mandible, truncal obesity[6] and a very small penis. Seizures are frequently secondary to hypoglycemia. Some genetic variations have an impact upon intellectual capacity.[7]
The majority of reported cases have been of Mediterranean or Semitic origin, with numerous patients in Israel, Ecuador, Turkey and in the Bahamas.
Treatment
Administration of GH has no effect on IGF-1 production, therefore treatment is mainly by biosynthetic IGF-1.
Homo floresiensis
Recent publications have proposed that Homo floresiensis represented a population with widespread Laron syndrome.[8][9]
References
- ^ synd/2825 at Who Named It?
- ^ Laron Z, Pertzelan A, Mannheimer S (1966). "Genetic pituitary dwarfism with high serum concentation of growth hormone--a new inborn error of metabolism?". Isr. J. Med. Sci. 2 (2): 152–5. PMID 5916640.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Laron Z (2004). "Laron syndrome (primary growth hormone resistance or insensitivity): the personal experience 1958-2003". J. Clin. Endocrinol. Metab. 89 (3): 1031–44. doi:10.1210/jc.2003-031033. PMID 15001582.
- ^ http://www.thaindian.com/newsportal/sports/laron-dwarfs-in-south-america-may-hold-secrets-to-cancer-cure_10085608.html
- ^ Hwa V, Camacho-Hübner C, Little BM; et al. (2007). "Growth hormone insensitivity and severe short stature in siblings: a novel mutation at the exon 13-intron 13 junction of the STAT5b gene". Horm. Res. 68 (5): 218–24. doi:10.1159/000101334. PMID 17389811.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ Laron Z, Ginsberg S, Lilos P, Arbiv M, Vaisman N (2006). "Body composition in untreated adult patients with Laron syndrome (primary GH insensitivity)". Clin. Endocrinol. (Oxf). 65 (1): 114–7. doi:10.1111/j.1365-2265.2006.02558.x. PMID 16817829.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Shevah O, Kornreich L, Galatzer A, Laron Z (2005). "The intellectual capacity of patients with Laron syndrome (LS) differs with various molecular defects of the growth hormone receptor gene. Correlation with CNS abnormalities". Horm. Metab. Res. 37 (12): 757–60. doi:10.1055/s-2005-921097. PMID 16372230.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Hershkovitz I, Kornreich L, Laron Z (2007). "Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron syndrome)". Am. J. Phys. Anthropol. 134 (2): 198–208. doi:10.1002/ajpa.20655. PMID 17596857.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Culotta E (2007). "Paleoanthropology. The fellowship of the hobbit". Science. 317 (5839): 740–742. doi:10.1126/science.317.5839.740. PMID 17690271.
External links
- Laron+syndrome at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
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