New autism loci discovered

Written byElie Dolgin

| 2 min read

Two large-scale genetic analyses have turned up a trio of new sites associated with autism, including a large-effect allele that seems to reduce the risk of developing the debilitating brain disorder, researchers reported today (Nov. 12) at the__ linkurl:American Society of Human Genetics__ meeting;http://www.ashg.org/2008meeting/ in Philadelphia. Last year, the Autism Genome Project Consortium performed the largest genome-wide linkage scan to date with around 10,000 SNPs in 1,181 families with at least two affected individuals. The group flagged a handful of genomic regions harboring linkurl:autism;http://www.the-scientist.com/2008/6/1/26/1/ susceptibility genes, although none of the linkage results were statistically significant linkurl:(__Nat Genet__, 39:319-328, 2007).;http://www.nature.com/ng/journal/v39/n3/abs/ng1985.html Now, a team led by linkurl:Dan Arking,;http://www.hopkinsmedicine.org/geneticmedicine/People/Faculty/Arking.html a geneticist at Johns Hopkins University, has ramped up the SNP count to include around 500,000 markers in 802 affected pairs of siblings. They then eliminated all the error-prone or uninformative SNPs to amass a collection of 180,000 high-quality markers for their analysis. "It's the cleanest best set of markers you can imagine," Arking said at a press conference. This enhanced genome-wide scan proved effective. Arking's team discovered two regions of significant linkage that had not been implicated before with the disease -- one at the tip of chromosome 20's short arm, and one at the end of chromosome 6's long arm. Arking, together with linkurl:Lauren Weiss,;http://psych.ucsf.edu/faculty.aspx?id=2774 a molecular geneticist at the University of California, San Francisco, also used the SNP dataset to perform familial association mapping in 1,594 parent-offspring trios to hunt for common variants of major effect linked to the disorder. At first, they did not find any genome-wide significant results. Additional assays, however, revealed a hitherto unidentified site on chromosome 5 where one particular allele was transmitted less often than expected to autistic individuals whose parents carried the allele. Thus, this allele, although only found in 4% of the population as a whole, likely confers some protection against autism, Arking and Weiss argued. This "protective allele" fell near the linkurl:semaphorin;http://www.the-scientist.com/article/display/21491/ 5A (__SEMA5A__) gene, which is involved in axonal guidance during neural development. The researchers compared brain slices of 20 autistic individuals with 10 controls and found that __SEMA5A__ had much lower expression levels in the autistic brains, further implicating this novel locus with autism. Arking and Weiss will present their findings in a linkurl:talk;http://www.ashg.org/2008meeting/abstracts/fulltext/f22475.htm on Saturday (Nov. 15) and in a linkurl:poster;http://www.ashg.org/cgi-bin/2008/ashg08s?author=weiss%20l&sort=ptimes&sbutton=Detail&absno=22118&sid=338373 on Friday (Nov. 14).

New autism loci discovered

The Scientist ARCHIVES

Become a Member of

Meet the Author

Elie Dolgin

Related Research Resources

What Is the Amniotic Fluid Composed of?

Research Resources

Podcasts

Webinars

Videos

Infographics

eBooks

Advancing Drug Discovery with Complex Human In Vitro Models

Redefining Immunology Through Advanced Technologies

Ensuring Regulatory Compliance in AAV Manufacturing with Analytical Ultracentrifugation

Skip the Wait for Protein Stability Data with Aunty

Products

Product News

Sino Biological's Launch of SwiftFluo® TR-FRET Kits Pioneers a New Era in High-Throughout Kinase Inhibitor Screening

SPT Labtech enables automated Twist Bioscience NGS library preparation workflows on SPT's firefly platform

Nuclera eProtein Discovery System installed at leading Universities in Taiwan

BRANDTECH Scientific Introduces the Transferpette® pro Micropipette: A New Twist on Comfort and Control