A Study Of Laron Syndrome

Laron Syndrome is another type of dwarfism that comes about from the lack of ability of the growth hormone receptors. What seems to be a good thing is that with the short stature, there is less chance for diabetes or cancer.

From the wikipedia article on Laron Syndrome HERE

Laron syndrome, or Laron-type dwarfism, is an autosomal recessive disorder characterized by an insensitivity to growth hormone (GH), caused by a variant of thegrowth hormone receptor. It causes short stature and a resistance to diabetes and cancer.

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]Eponym

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 inserum, has been termed Laron syndrome.

Pathophysiology

Laron syndrome has an autosomal recessive pattern of inheritance.

Molecular genetic investigations have shown that this disorder is mainly associated with mutations in the gene for the GH receptor. These can result in defectivehormone binding to the ectodomain or reduced efficiency of dimerization of the receptor after hormone occupancy. There are exceptionally low levels of insulin-like growth factor (IGF-1) and its principal carrier protein, insulin-like growth factor binding protein 3.

A related condition involving postreceptor insensitivity to growth hormone has been associated with STAT5B.[4]

Clinical characteristics

The principal feature of Laron syndrome is abnormally short stature (dwarfism). Physical symptoms include: prominent forehead, depressed nasal bridge, underdevelopment of mandible, truncal obesity[5] and a very small penis. Seizures are frequently seen secondary to hypoglycemia. Some genetic variations have an impact upon intellectual capacity.[6]

The majority of reported cases have been of Arabic or Semitic origin, with numerous patients in Israel, Saudi Arabia, Egypt, Iraq, and remote villages in Ecuador withSephardic roots.[7][8]

In 2011, it was reported that people with this syndrome in the Ecuadorian villages are resistant to cancer and diabetes and are somewhat protected against aging.[7][9][10] This is consistent with findings in mice with a defective growth hormone receptor gene.[8]

Treatment

Administration of GH has no effect on IGF-1 production, therefore treatment is mainly by biosynthetic IGF-1. IGF-1 must be taken before puberty to be effective.[8]

IPLEX (Mecasermin rinfabate) is composed of recombinant human IGF-1 (rhIGF-1) and its binding protein IGFBP-3. It was approved by the U.S. Food and Drug Administration (FDA) in 2005 for treatment of primary IGF-1 deficiency or GH gene deletion.[11][12] Side effects from IPLEX are hypoglycemia.

IPLEX’s manufacturing company, Insmed, can no longer develop proteins and can no longer manufacture IPLEX as of a statement released in January 2012.

Prognosis

People with Laron syndrome have strikingly low rates of cancer and diabetes.[8]

Homo floresiensis

Recent publications have proposed that Homo floresiensis represented a population with widespread Laron syndrome.[13][14] This hypothesis has received criticism and is unconfirmed.

Me: The main thing to take away from learning even more about dwarfism is that there are many factors and causes that can causes stunted growth and height but only a few that can results in tallness and increased height. For Laron Syndrome, the growth hormone receptors just don’t work properly so the entire growth process stops close to the very beginning. There is little IGF-1 or the IGF-1 transport proteins either. However, the people who are affected with this condition should still be able to possibility increase their height, not through the traditional growth hormone therapy ,but from stimulating the chondrocytes to proliferate in other ways that have been described on this website. 

What is really amazing for this type of dwarfism is that people who seem to be inflicted by this disorder have extremely low rates of cancer or diabetes, and seems to have very long life expectancies. 

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