Featured Research

from universities, journals, and other organizations

Autism Risk Higher In People With Gene Variant

Date:
January 11, 2008
Source:
NIH/National Institute of Mental Health
Summary:
A new study strengthens evidence that a gene, CNTNAP2, is involved in autism, and suggests that the link is strongest when a variation in the gene is inherited from moms, rather than dads. The gene encodes a protein that's known to mediate interactions between brain cells and that appears to enable a crucial aspect of brain-cell development. A gene variant that altered either of these activities could have significant impact.

Scientists have found a variation in a gene that may raise the risk of developing autism, especially when the variant is inherited from mothers rather than fathers.

Inheriting the gene variant does not mean that a child will inevitably develop autism. It means that a child may be more vulnerable to developing the disease than are children without the variation.

The gene, CNTNAP2, makes a protein that enables brain cells to communicate with each other through chemical signals and appears to play a role in brain cell development. Previous studies have implicated the gene in autism, and in this study researchers were able to link a specific variation in its structure to the disease.

Results of the study were reported online January 10 in the American Journal of Human Genetics, by Aravinda Chakravarti, Ph.D., Dan E. Arking, Ph.D., and colleagues from the Johns Hopkins University School of Medicine, with Edwin Cook, M.D., and colleagues from the University of Illinois at Chicago.

"Autism is highly heritable. Identifying the genes involved is crucial to our ability to map out the pathology of this isolating and sometimes terribly disabling disease, which currently has no cure," said NIMH Director Thomas R. Insel, M.D.

Autism is a developmental brain disorder that impairs basic behaviors needed for social interactions, such as eye contact and speech, and includes other symptoms, such as repetitive, obsessive behaviors. The symptoms sometimes cause profound disability, and they persist throughout life. Treatments may relieve some symptoms, but no treatment is fully effective in treating the core social deficits.

Although the cause of autism is not yet clear, studies of twins have shown that genes play a major role. It is likely that variations in many genes, influenced by environmental factors, interact during brain development to cause vulnerability to the disease. These genes have yet to be identified. Several candidates, including CNTNAP2, have been suggested.

The assertion that the CNTNAP2 gene appears to be involved is strengthened by the fact that each of the different analytical approaches the researchers used in this study led to the same conclusion. Results were replicated in a second, larger group of participants, further implicating the gene. Together, the two groups of participants comprised one of the largest autism studies reported to date.

The first part of the study included 145 children with autism and their parents, from families that had two or more children with autism. Using a technique called genome-wide linkage analysis, the researchers found that a chromosome, 7q35, appeared to be linked to the disease.

Looking deeper into that chromosome, they identified a gene -- CNTNAP2 -- that contained a variant relevant to autism. Where a single segment of the genetic code could contain either the chemical base adenine or thymine, children with autism tended to have inherited the thymine variant.

To validate these findings, the researchers studied a separate group of participants; 1,295 children with autism and their healthy parents. The scientists again found that children with autism had higher rates of the thymine variant in the CNTNAP2 gene than would be expected to occur by chance.

When the researchers combined the data from the studies, they found that children with autism were about 20 percent more likely to have inherited the thymine variant from their mothers than from their fathers.

"This is a common variant. People inherit it all the time. Our finding that it's associated with autism more often when it's inherited from mothers is intriguing, but needs to replicated," Chakravarti said.

The role of CNTNAP2 in brain-cell development suggested by earlier studies has to do with differentiation, the process by which precursor cells develop into the different kinds of cells of the body. CNTNAP2 carries the genetic code for a protein, part of a family called neurexins, that appears to enable the precursor cells to develop myelinated axons. These are projections through which brain cells send each other electrical impulses essential for normal brain function at especially high speeds.

"CNTNAP2 is an excellent candidate gene for autism," Chakravarti said. "It encodes a protein that's known to mediate interactions between brain cells and that appears to enable a crucial aspect of brain-cell development. A gene variant that altered either of these activities could have significant impact."

Journal reference: Arking DE, Cutler DJ, Brune CW, Teslovich TM, West K, Ikeda M, Rea A, Guy M, Lin S, Cook Jr. EH, Chakravarti A. A common Genetic Variant in the Neurexin-Superfamily Member CNTNAP2 Increases Familial Risk of Autism. American Journal of Human Genetics, online ahead of print, January 10, 2008.

The research was funded by the National Institute of Mental Health (NIMH), part of the National Institutes of Health.


Story Source:

The above story is based on materials provided by NIH/National Institute of Mental Health. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute of Mental Health. "Autism Risk Higher In People With Gene Variant." ScienceDaily. ScienceDaily, 11 January 2008. <www.sciencedaily.com/releases/2008/01/080110123933.htm>.
NIH/National Institute of Mental Health. (2008, January 11). Autism Risk Higher In People With Gene Variant. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2008/01/080110123933.htm
NIH/National Institute of Mental Health. "Autism Risk Higher In People With Gene Variant." ScienceDaily. www.sciencedaily.com/releases/2008/01/080110123933.htm (accessed September 2, 2014).

Share This




More Mind & Brain News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
Coffee Then Napping: The (New) Key To Alertness

Coffee Then Napping: The (New) Key To Alertness

Newsy (Aug. 30, 2014) Researchers say having a cup of coffee then taking a nap is more effective than a nap or coffee alone. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
Baby Babbling Might Lead To Faster Language Development

Baby Babbling Might Lead To Faster Language Development

Newsy (Aug. 29, 2014) A new study suggests babies develop language skills more quickly if their parents imitate the babies' sounds and expressions and talk to them often. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins