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Missing genes linked to autism

26 March 2007
Appeared in BioNews 400

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 of autism, especially in families with just one affected child. Lead author Jonathon Sebat, of Cold Spring Harbour Laboratory, said the data showed there could be many 'autism genes' in the genome.

Autism - along with several related conditions together known as autistic spectrum disorders - 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. Although autism often runs in families, many children are born to parents with no history of the condition.

The team studied 118 families with just one affected child, 47 with multiple children with an autism spectrum disorder, and 99 unaffected families. They looked at DNA samples from the participants, to try and detect regions that were either deleted or duplicated in affected individuals. The researchers identified such a genetic change in over 10 per cent of the children, most of which were not present in either parent. Their locations varied between individuals, involving many different genes.

Most of the changes were deletions, leading to missing copies of genes - in one case, 27 genes were encompassed by a single deletion. Since the spontaneous changes were typically present in families with only one affected child, testing for these variations may allow doctors to inform parents about their risk for having a second child with autism, according to Sebat. The genetics of autism may be different in families with several affected children, he says.

'The majority of genetic studies to date have focussed on the minority of families with multiple affected kids', Sebat told the Scientist magazine, adding 'the sporadic cases might be a rich source of genetic information'. The team now plans to screen at least another 2000 further families, using higher-resolution technology, to try and detect more genetic changes associated with autism.

Copy number linked to autism
The Scientist |  15 March 2007
CSHL Scientists Confirm Genetic Distinction Between Heritable and Sporadic Cases of Autism
Innovations Report |  21 March 2007
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 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...
7 August 2006 - by Letitia Hughes 
Researchers at the University of Washington, US, have found that different genes may be responsible for causing autism in boys than girls. Reporting in the Journal of Molecular Genetics last week, they have found evidence for two genetic subtypes of autism; both male versus female and also...
29 July 2005 - by BioNews 
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...
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...
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