Saturday, August 13, 2011

The mutated SHANK3 gene, its effect on Neuronal Synapses and Autism

The following is an extract from an article published in the New England Journal of Medicine (July 14, 2011). The author is Martha Herbert MD, PhD of the Mass General Hospital and Harvard Medical School. She is a research scientist with great interest in Autism. She has presented at the annual conference of the NY Metro Chapter in New York as well as the NAA annual conferences.

The neuron talk to each other and send signals from brain to other organs by releasing chemicals at their very ends. The exchange of these chemicals occurs at the synapses (the ends of the neurons). SHANK3 gene is known to facilitate such transactions. Research scientists have developed a clone of mice who are deficient in beta type of SHANK3 genes (SHANK3B-/-). These mice exhibit clinical and social behavior that is similar to autism in humans. The biopsies of the brains of these mice also show increased filaments (dendrites) of these neurons which looks like a jumble. The part of the brain called Striatum was larger in the SHANK3B-/- mice. This was thought to be compensatory on the part of the brain in an attempt to increase the synapses and communication that is defective due to the genetic mutation. It is known that the brains of humans with autism are larger and have excessive dendrites.

SHANK3 gene is also present in the gut and other tissues. SHANK3 gene has two other isoforms (alpha and gamma) and the level of activity of those isoforms may be related to the variability in cases of autism and may explain the improvement in clinical symptoms and social behavior that is sometimes seen after certian treatments and high fever. Dr. Herbert's article was published in:
The New England Journal of Medicine. Vol: 365, Page 173. 14 July 2011

If you wish to read the full scientific article, please contcat me at
Posted by Khalid Rehman MD, Chair Advocacy and Awareness Committee,
National Auatim Association, New York Metro Chapter.

1 comment:

Ultimate Autism Guide said...

This study is very interesting. It is fascinating to see how the mutation in SHANK3 resulted in changes in the brain structure of the mice. It is interesting, however, that very few individuals with autism actually have a mutation at SHANK3. This may be another indication of how complex the etiology of autism is.