Page URL:

Multiple gene mutations linked to autism

29 July 2005
By BioNews
Appeared in BioNews 319

In two separate studies, scientists working at Vanderbilt University in Tennessee, US have shown that a faulty gene involved in controlling levels of the brain chemical serotonin is linked to an increased risk of autism.

The first study, published in the American Journal of Human Genetics, shows that many different mutated forms of the serotonin transporter gene (SERT) are associated with the condition. In the second, published online in the Proceedings of the National Academy of Sciences (PNAS), the researchers show how these SERT mutations may disrupt serotonin signalling in autism. The findings could lead to more targeted drug therapies for some children with autism, say the teams.

Autism is a lifelong developmental disability that typically appears during the first three years of life. The disorder affects social and language skills, and the way in which a child relates to people, objects and events. Autism often runs in families, suggesting that it has a genetic basis, although it is thought that the combined effects of at least ten different genes are involved. Previous research has shown that around 25 per cent of people with autism have raised levels of serotonin in their blood - suggesting that this chemical is involved in the disorder. Also, the symptoms of autism improve in some patients treated with selective serotonin reuptake inhibitor (SSRI) drugs such as Prozac, which increase the amount of serotonin available to cells in the brain.

In the latest research, James Sutcliffe and colleagues at the Vanderbilt Center for Molecular Neuroscience followed up earlier work showing a weak link between one version of the SERT gene and autism. They looked at DNA samples from 120 families affected by autism, and identified 19 different SERT gene mutations present in those with more than one affected male. In the second study, Randy Blakely and colleagues at the Vanderbilt Kennedy Center for Research on Human Development showed that the faulty versions of SERT affect serotonin signalling in the brain.

The SERT gene makes a protein whose normal job is to 'vacuum up' excess serotonin in the brain. The PNAS study shows that other brain proteins that fine-tune SERT activity were unable to control five of the ten faulty SERT proteins examined. 'We were stunned because the cell just can't 'talk' to these SERT proteins in the normal way', said Blakely. He added that although it was impossible to extrapolate from a molecule to a person, 'it is striking that these mutations, which do not allow proper communication with SERT, show up in a disorder fraught with communication problems'.

Blakely and Sutcliffe say that the findings could lead to new drug therapies for autism. Sutcliffe adds that it may also be possible to use genetic testing 'to predict which kids would respond positively to particular SSRI medications'. Last week, French researchers also said they were developing a risk assessment test for autism, based on four other genes that affect a person's susceptibility to the condition. The team, from the company IntegraGen SA, aims to launch the test in 2006, and hopes that it will be used to help confirm diagnoses, and also to assess the risk of autism in children too young to show symptoms.

Discovery of faulty gene offers hope on autism
The Times |  26 July 2005
Multiple genetic 'flavors' may explain autism
Medical News Today |  27 July 2005
25 October 2009 - by Dr Rebecca Robey 
US scientists have identified a genetic trait that is strongly associated with autism. The genetic change does not involve a mutation within the DNA sequence of a gene but instead involves an alteration in the physical structure of the DNA which affects the way a gene is turned on and off. The researchers hope that the new findings will lead to novel ways to diagnose and treat autism....
21 September 2009 - by Professor Richard Ashcroft 
Autism spectrum disorder (ASD) is rarely far from the news. ASD is a complex, and as yet poorly understood, pervasive developmental disorder. People with ASD display a triad of impairments in social communication, social interaction, and social imagination (1). The impact of these impairments on children and adults with ASD, and on their families, can vary enormously. However, a common reaction to ASD is fear: fear that my child may develop ASD; fear that my child with ASD will suffer;
26 March 2007 - by Dr Jess Buxton 
Many cases of autism could be linked to spontaneous genetic changes that result in large chunks of missing DNA, according to a new US study. The research, published early online in Science, shows that so-called 'copy number variants' could be an important factor in the appearance...
26 February 2007 - by Dr Laura Bell 
Recent research published online in the journal Nature Genetics has revealed new genetic variations which may contribute to autism. Autism, along with related conditions such as Asperger syndrome, is characterised by a range of severity and symptoms. The conditions are therefore collectively known as autistic spectrum...
16 February 2007 - by BioNews 
By Dr Laura Bell New research recently published in the journal Science provides hope for the treatment of Rett syndrome, a rare but severe childhood neurological disorder. Nearly 10,000 children in the UK are affected by Rett syndrome which, in its early stages, has similar symptoms to autism. The condition...
22 July 2005 - by BioNews 
The identification of a gene involved in autism could lead to a new test for children at risk of developing the condition, French researchers say. The scientists, based at the company IntegraGen SA, have shown that variations in a gene called PRKCB1 are 'strongly associated' with autism. The finding, published...
19 July 2004 - by BioNews 
An international team of 170 scientists has embarked on a search for genes that influence a child's risk of developing autism. The project will study 6000 DNA samples from around 1,200 families affected by the developmental disorder, in order to track down the estimated 15-20 genes thought to be...
5 April 2004 - by BioNews 
Variations in a gene involved in energy production could be linked to autism, US researchers say. A team based at the Mount Sinai School of Medicine in New York studied 720 people from 411 families, who all have either autism, or the related condition autistic disorder. They found that variations...
Log in 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.