Difference between revisions of "Abnormal Cellular/Synaptic Growth Hypothesis"

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==Abnormal Cellular/Synaptic Growth Hypothesis==
 
==Abnormal Cellular/Synaptic Growth Hypothesis==
  
This hypothesis came about from studies on single gene disorders like fragile X where patients with the disorder have a high incidence rate.  Fragile X Syndrome, for example, has a ASD prevalence rate of 15% and Tuberous sclerosis has an ASD prevalence of 25-60 percent.
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This hypothesis came about from studies on single gene disorders where patients with the disorder have a high incidence rate of ASD, like fragile X with an ASD prevalence rate of 15% and Tuberous sclerosis, which has a prevalence rate anywhere between 25%-60%. Studies of these disorders can illuminate which biological pathways may be responsible for ASD phenotypes. 
  
 
Studies of Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndromes found that the two syndromes associate susceptibility to [[Autism Spectrum Disorders]] with [[Macrocephaly| macrocephaly]].  [[Macrocephaly]] is relatively common among ASD patients with an estimated prevalence rate of 20%.   
 
Studies of Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndromes found that the two syndromes associate susceptibility to [[Autism Spectrum Disorders]] with [[Macrocephaly| macrocephaly]].  [[Macrocephaly]] is relatively common among ASD patients with an estimated prevalence rate of 20%.   
  
Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndrome are caused by NF1, TSC1/TSC2, and PTEN. These proteins act as negative effectors of mTORC1, which is a major regulator of cellular growth in mitotic cells.  It is thought that mutations enhance the MTORC1 complex which is activated by a sequential kinase cascade downstream of the phosphoinositide-3 kinase pathway. This pathway can be modulated by serotonin.<sup>1</sup>
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Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndrome are caused by NF1, TSC1/TSC2, and PTEN. The tuberous schlerosis complex has GAP activity against GTP binding protein Rheb which results in the inhibition of rapamycin kinase (mTOR).  These proteins act as negative effectors of mTORC1, which is a major regulator of cellular growth in mitotic cells.  It is thought that mutations enhance the MTORC1 complex which is activated by a sequential kinase cascade downstream of the phosphoinositide-3 kinase pathway. This pathway can be modulated by serotonin.<sup>1</sup>
  
The tuberous schlerosis complex has GAP activity against GTP binding protein Rheb which results in the inhibition of rapamycin kinase (mTOR). 
 
  
 
[[Theories for Causes|Back to Theories for Causes]]
 
[[Theories for Causes|Back to Theories for Causes]]

Revision as of 13:56, 26 October 2009

Abnormal Cellular/Synaptic Growth Hypothesis

This hypothesis came about from studies on single gene disorders where patients with the disorder have a high incidence rate of ASD, like fragile X with an ASD prevalence rate of 15% and Tuberous sclerosis, which has a prevalence rate anywhere between 25%-60%. Studies of these disorders can illuminate which biological pathways may be responsible for ASD phenotypes.

Studies of Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndromes found that the two syndromes associate susceptibility to Autism Spectrum Disorders with macrocephaly. Macrocephaly is relatively common among ASD patients with an estimated prevalence rate of 20%.

Tuberouse Schlerosis and Cowden/Lhermitte-Cuclos Syndrome are caused by NF1, TSC1/TSC2, and PTEN. The tuberous schlerosis complex has GAP activity against GTP binding protein Rheb which results in the inhibition of rapamycin kinase (mTOR). These proteins act as negative effectors of mTORC1, which is a major regulator of cellular growth in mitotic cells. It is thought that mutations enhance the MTORC1 complex which is activated by a sequential kinase cascade downstream of the phosphoinositide-3 kinase pathway. This pathway can be modulated by serotonin.1


Back to Theories for Causes

References

1. Bourgeron T. A synaptic trek to autism. Curr Opin Neurobiol. 2009 Apr;19(2):231-4 PMID 19545994