Wednesday, January 16, 2008

Choromosome 16 & Autism Linked...

Ya'll know that my son (Noah) ... has Mosaic Trisomy 16 ... well if you didn't you do now.. lol.. anyway - we've thought that he has had autistic traits in the past... just certain things that make you think that just SOMETHING isn't quite right... but the only thing that holds us back from him being tested or considered or whatever... is that he is a social bug :) LOL... he loves to carry on convos, and everything else... he likes his friends... but he gets very very upset if he's alone... well, that is the oppisite of what "autistic" kids are usually like... so I donno what to think, but then I read this...,0,1961343.story

Study finds link between genetic flaws, autism


January 10, 2008

Scientists have pinpointed relatively rare chromosomal flaws that they say not only substantially increase the risk of autism spectrum disorders in some children, but also provide a new target for genetic screening.

Findings by a collaborative team of researchers at 14 leading universities and medical centers now confirm that specific telltale defects on chromosome 16 can result in autism in about 1 percent of people who inherit the flaws.

There are 46 chromosomes in each of the 10 trillion cells that make up the human body. Results from the investigation, which was led by scientists at Children's Hospital in Boston, confirm earlier genetic research, including studies by scientists at Cold Spring Harbor Laboratory.Using sensitive new research tools, members of the Autism Consortium scanned the entire human genome and discovered that sections of chromosome 16 are either deleted or duplicated in some people with autism spectrum disorders. These neurodevelopmental conditions can range from mild to severe, and include symptoms ranging from learning delays to more complex problems in which children avoid social interaction or do not speak.

Dr. Bai-Lin Wu, a senior author of the study that was released online yesterday by the New England Journal of Medicine, said roughly 10 percent of all cases of autism can be traced to an underlying genetic cause.

"When you scan the whole genome, you scan every chromosome," Wu said yesterday. "But chromosome 16 was the one we found that had significant difference."

Because identifiable miscues on chromosome 16 can be isolated, he said, his laboratory can seek out the variation and tell parents interested in determining whether their child possesses a flaw. "This is the first [autism] study that combines research findings with clinical applications," Wu said of the screening possibility that the new analysis offers.

Dr. Michael Wigler, a molecular geneticist at Cold Spring Harbor Laboratory who has led a series of major studies on the genetics of autism, said the consortium's work helps elucidate its molecular underpinnings.

"I think this is an extremely well-done study," Wigler said yesterday. "It proves our theory that autism can be caused by spontaneous mutations," he said of DNA missteps that can occur randomly. "Sometimes the mutation can cause disease in the carrier and sometimes it doesn't.
"This locus," he said of the spot on chromosome 16 that scientists found to be flawed, "was actually first found by us. But we do not do clinical testing."

Wu said the study involved examining the DNA of more than 3,000 people, which included 1,441 autistic children, DNA from their parents and controls, who are people without the disorder.

The team found a segment of 25 genes on chromosome 16 that was missing in some of the children in the study. None of their parents possessed the flaw, which suggests - as Wigler has argued all along - that autism can occur as a spontaneous mutation. However, in other children whose DNA was analyzed, there was a duplication of chromosome 16 that also occurred in at least one parent.

Portia Iversen, a Los Angeles-area activist who helped develop a large DNA database now maintained at the National Institutes of Health in Bethesda, Md., said genetic studies will help demystify many of the unknowns about autism, which is estimated to affect 1 in every 150 children nationwide.

"We've known for some time that chromosome 16 is one of the hot spots in autism," added Iversen, the mother of a teenage son with the condition. "There were studies as early as the 1970s and '80s that showed autism is genetic and that if you have one child with autism, your chances are much higher of having another child with it."

The DNA database Iversen organized invited families to contribute blood samples. The database was used by Cold Spring Harbor Laboratory scientists for their genetic research.

Dr. Steven Pavlakis, director of pediatric neurology at Maimonides Medical Center in Brooklyn, applauded the new study by Wu and his colleagues.

"This tells you that something genetic underlies at least a portion of cases," he said. "We don't know how these cases differ from each other clinically."

No comments: