Page URL:

Genetics of uncontrolled brain growth in autism identified

26 March 2012
Appeared in BioNews 650

Faulty genetic mechanisms particularly active in early life may lead to people developing autism, research suggests.

A study, led by Dr Eric Courchesne at the University of California, in the USA, investigated changes in the DNA and RNA in post-mortem brains of patients with autism. They found important differences in the expression of genes between children and adults with autism, and compared to controls.

Earlier work by Dr Courchesne suggested that in people with autism the prefrontal cortex - a region of the brain associated with social and communication skills - is larger than normal. The current study goes some way to suggesting why this may be.

The researchers found that many of the misfiring genes in the brains of the autistic children studied were involved in brain cell growth, leading to an excess of brain cells that Dr Courchesne had previously identified. The problem would appear to begin during the second and third trimester of pregnancy, when most brain cells are created.

Dr Courchesne explained: 'Essentially, the wiring pattern for the brain goes wrong and you don't get normal development'.

However, by examining the DNA and RNA profiles of brain tissue from adults with autism, the researchers also uncovered evidence that the brains of people with autism may re-wire in an attempt to counteract the effects of the disorder.

Dr Courchesne says that these changes 'are telling us that the brain development problem hasn't stopped. It is on-going. There may be signals or genetic changes that are attempting to deal with the original problem. That would seem to offer a potential target for pharmaceuticals to improve the remodelling'.

Nonetheless, other researchers dispute that there is an increase in the size of the brain in autistic patients. In particular, one study demonstrated an increase in the incidence of microcephaly, a condition in which people are born with small brains, in patients with autism.

However, the current study is the first to identify genetic changes which can explain a change in brain size and structure in people with autism. Dr Courchesne said: 'We are getting at core knowledge. If we confirm that the starting point is gene activity, we can do something about it, because gene activity can be modified'.
2 March 2015 - by Dr Meghna Kataria 
One of the genes behind the dramatic evolutionary enlargement of the human brain has been identified. By greatly increasing the number of cells in important brain regions, the gene in question might have helped humans develop cognitive abilities unrivalled in the animal kingdom...
7 April 2014 - by Dr Naqash Raja 
A map showing where different genes are turned on and off in the fetal human brain has been published in the hope it will give important clues about the origins of disorders...
10 June 2013 - by Siobhan Chan 
A large, complex gene network in people with autism has been identified by researchers at the University of Oxford...
21 January 2013 - by Dr Victoria Burchell 
Rare genetic variants may have a significant impact on a person's risk of developing autism, research suggests...
24 September 2012 - by Dr Lux Fatimathas 
The first detailed maps of genetic activity in the human brain have been published online by scientists...
13 June 2011 - by Dr Lux Fatimathas 
American researchers have linked hundreds of spontaneous genetic mutations to the group of psychological syndromes called autism spectrum disorders (ASDs)...
31 May 2011 - by Mehmet Fidanboylu 
Gene activity in two brain regions is different in autism, scientists say. A US study found activity patterns were similar in the frontal and temporal lobes of people with autism, despite the lobes having different functions...
6 September 2010 - by Dr Vivienne Raper 
Tests to diagnose learning disabilities, autism and blindness using a child's whole genome could become a reality in clinics by 2011, according to a leading Dutch academic...
14 June 2010 - by Sandy Starr 
Results from the largest international study of its kind into autism strongly suggests that rare genetic variants contribute far more than common variants to the risk of developing the condition....
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.