New Study Findings

iVillage Member
Registered: 05-16-2006
New Study Findings
Sat, 03-17-2007 - 8:32am

I got this from wwww.aboard.org
Enjoy

****************************************************************************
DNA 'glitches' tied to autism
From correspondents in Washington

March 16, 2007 12:00

Article from: ReutersFont size: + -
Send this article: Print Email
LITTLE glitches in the DNA of people with autism suggest that the disease might be caused by as many as 100 different genes, researchers reported overnight.

The study is one of several new reports on autism in recent months, which have shown it is far more common and more complex than many experts had believed.

"These findings certainly complicate the search for genes contributing to autism. These are rare changes, dispersed across the genome, and they tell us that autism may be the final common path for many different genetic abnormalities," said Dr Thomas Insel, director of the National Institute for Mental Health, which helped fund the study.

The small changes are not what people usually think of as genetic mutations but are called copy number variations - extra copies or missing stretches of DNA.

For instance, one child with Asperger syndrome was missing DNA from a stretch of 27 genes.

The findings suggest that autism spectrum disorder may involve 100 or more genes, the researchers report in the journal Science.

Experts know autism has a genetic cause, and in February the US Centres for Disease Control and Prevention reported it affects about one in every 150 children.

For the study, Dr Jonathan Sebat of the Cold Spring Harbour Laboratory in New York and colleagues across the United States, in Finland and in Britain looked at the DNA of people in 264 families.

"We performed whole-genome scans on all parents, patients and unaffected children," the researchers wrote.

New technology to sequence genes rapidly, as well as several published sequences of the human genome, have helped scientists do this in recent years.

Usually, tests of DNA of people with diseases show that everyone in a family who has the disorder carries the same mutation or pattern of mutations.

But that's not the case here. The researchers found numerous spontaneous mutations in 14 of 195 people with autism spectrum disorders compared to two of 196 unaffected people.

And of the 14 autism patients with mutations, only two had relatives with autism.

"Our results show conclusively that these tiny glitches are frequent in autism, occurring in at least 10 per cent of cases, and primarily in the sporadic form of the disease, which accounts for 90 per cent of affected individuals," Dr Sebat said.

Autism is marked by a variety of difficulties in social interaction and behaviour, and range from the awkwardness of Asperger syndrome to severely debilitating repetitive behaviours and an inability to speak.

The recent studies suggest that these important abilities are scattered throughout the human genome, and that small changes anywhere can have broad effects.

"This is just one piece of information that is going to add to the evolving story but more is needed