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Laron syndrome due to postreceptor defect; growth hormone insensitivity due to postreceptor defect; Laron-type dwarfism
Laron syndrome due to postreceptor defect; growth hormone insensitivity due to postreceptor defect; Laron-type dwarfism


==Overview==
==[[Laron syndrome overview|Overview]]==
Laron syndrome is a [[autosomal recessive]] disorder characterized by an insensitivity to [[growth hormone]] (GH), caused by a variant of the [[growth hormone receptor]]. It causes [[short stature]].


==Historical perspective==
==[[Laron syndrome historical perspective|Historical Perspective]]==
It is named after Zvi Laron, the Israeli researcher who, with A. Pertzelan and S. Mannheimer, first reported the condition in 1966<ref>{{WhoNamedIt|synd|2825}}</ref><ref name="pmid5916640">{{cite journal |author=Laron Z, Pertzelan A, Mannheimer S |title=Genetic pituitary dwarfism with high serum concentation of growth hormone--a new inborn error of metabolism? |journal=Isr. J. Med. Sci. |volume=2 |issue=2 |pages=152-5 |year=1966 |pmid=5916640 |doi=}}</ref>, based upon observations which began in 1958.<ref name="pmid15001582">{{cite journal |author=Laron Z |title=Laron syndrome (primary growth hormone resistance or insensitivity): the personal experience 1958-2003 |journal=J. Clin. Endocrinol. Metab. |volume=89 |issue=3 |pages=1031-44 |year=2004 |pmid=15001582 |doi=}}</ref>


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.
==[[Laron syndrome classification|Classification]]==
===Homo floresiensis===
Recent publications have proposed that [[Homo floresiensis]] represented a population with widespread Laron syndrome.<ref name="pmid17596857">{{cite journal |author=Hershkovitz I, Kornreich L, Laron Z |title=Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron syndrome) |journal=Am. J. Phys. Anthropol. |volume=134 |issue=2 |pages=198-208 |year=2007 |pmid=17596857 |doi=10.1002/ajpa.20655}}</ref><ref name="pmid17690271">{{cite journal |author=Culotta E |title=Paleoanthropology. The fellowship of the hobbit |journal=Science |volume=317 |issue=5839 |pages=740-2 |year=2007 |pmid=17690271 |doi=10.1126/science.317.5839.740}}</ref>


==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]]. Laron syndrome is a [[autosomal recessive]] disorder.


==Epidemiology and Demographics==
==[[Laron syndrome pathophysiology|Pathophysiology]]==
The majority of reported cases have been of Mediterranean or semitic origin, with numerous patients in Israel, Ecuador, Turkey and in the Bahamas.
==Diagnosis==
===Symptoms===
The principal feature of Laron syndrome is abnormally short stature ([[dwarfism]]).
Symptoms include:
*Truncal [[obesity]]<ref name="pmid16817829">{{cite journal |author=Laron Z, Ginsberg S, Lilos P, Arbiv M, Vaisman N |title=Body composition in untreated adult patients with Laron syndrome (primary GH insensitivity) |journal=Clin. Endocrinol. (Oxf) |volume=65 |issue=1 |pages=114-7 |year=2006 |pmid=16817829 |doi=10.1111/j.1365-2265.2006.02558.x}}</ref>
*[[Seizures]] are frequently secondary to [[hypoglycemia]].
*Some genetic variations have an impact upon intellectual capacity.<ref name="pmid16372230">{{cite journal |author=Shevah O, Kornreich L, Galatzer A, Laron Z |title=The intellectual capacity of patients with Laron syndrome (LS) differs with various molecular defects of the growth hormone receptor gene. Correlation with CNS abnormalities |journal=Horm. Metab. Res. |volume=37 |issue=12 |pages=757-60 |year=2005 |pmid=16372230 |doi=10.1055/s-2005-921097}}</ref>
===Physical Examination===
Physical exam findings include:
*[[Prominent forehead]]
*[[Depressed nasal bridge]]
*[[Under-development of mandible]]
*A [[Micropenis|very small penis]]


==Treatment==
==[[Laron syndrome causes|Causes]]==
Treatment may include administration of [[IGF-1]].
 
==[[Laron syndrome differential diagnosis|Differentiating Laron Syndrome from other Diseases]]==
 
==[[Laron syndrome epidemiology and demographics|Epidemiology and Demographics]]==
 
==[[Laron syndrome risk factors|Risk Factors]]==
 
 
 
==[[Laron syndrome natural history, complications and prognosis|Natural History, Complications and Prognosis]]==


==References==
==[[Laron syndrome diagnosis|Diagnosis]]==
{{Reflist|2}}
[[Laron syndrome history and symptoms|History and Symptoms]] | [[Laron syndrome physical examination|Physical Examination]] | [[Laron syndrome laboratory findings|Laboratory Findings]] | [[Laron syndrome CT|CT]] | [[Laron syndrome MRI|MRI]] | [[Laron syndrome echocardiography or ultrasound|Ultrasound]] | [[Laron syndrome other imaging findings|Other Imaging Findings]] | [[Laron syndrome other diagnostic studies|Other Diagnostic Studies]]


==Treatment==
[[Laron syndrome medical therapy|Medical Therapy]] | [[Laron syndrome surgery|Surgery]] | [[Laron syndrome primary prevention|Primary Prevention]] | [[Laron syndrome secondary prevention|Secondary Prevention]] | [[Laron syndrome cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Laron syndrome future or investigational therapies|Future or Investigational Therapies]]
==Case Studies==
:[[Laron syndrome case study one|Case #1]]





Latest revision as of 20:16, 19 September 2012

For patient information click here

Laron syndrome
Growth hormone
ICD-10 E34.3
ICD-9 259.4
OMIM 262500 245590
DiseasesDB 7262
MeSH D046150

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Assosciate Editor(s)-In-Chief: Prashanth Saddala M.B.B.S

Synonyms and keywords: Growth Harmone Receptor Deficiency; Growth hormone insensitivity syndrome; pituitary dwarfism II; Laron syndrome due to postreceptor defect; growth hormone insensitivity due to postreceptor defect; Laron-type dwarfism

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Laron Syndrome from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | CT | MRI | Ultrasound | Other Imaging Findings | Other Diagnostic Studies

Treatment

Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case #1


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