Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Common gene variants account for most of the genetic risk for autism

21.07.2014

Nearly 60 percent of the risk of developing autism is genetic and most of that risk is caused by inherited variant genes that are common in the population and present in individuals without the disorder, according to a study led by researchers at the Icahn School of Medicine at Mount Sinai and published in the July 20 edition of Nature Genetics.

"We show very clearly that inherited common variants comprise the bulk of the risk that sets up susceptibility to autism," says Joseph D. Buxbaum, PhD, the study's lead investigator and Director of the Seaver Autism Center for Research and Treatment and Professor of Psychiatry, Neuroscience and Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai. "But while families can be genetically loaded for autism risk, it may take additional rare genetic factors to actually produce the disorder in a particular family member."

Dr. Buxbaum and colleagues of the Population-Based Autism Genetics and Environment Study (PAGES) Consortium conducted a rigorous analysis of DNA sequence variations from an ongoing, comprehensive study of autism in Sweden.

Although autism is thought to be caused by an interplay of genetic and other factors, there has been no consensus on their relative contributions and the nature of its genetic architecture. Recently, evidence has been mounting that genomes of people with autism are prone to harboring de novo mutations - rare, spontaneous mutations that exert strong effects and can largely account for particular cases of the disorder.

Specifically, the current study found that about 52.4 percent of autism was traced to common and rare inherited variations, with spontaneous mutations contributing a modest 2.6 percent of the total risk.

"Many people have been focusing on de novo mutations, such as the ones that can occur in the sperm of an older father," explains Dr. Buxbaum. "While we find these mutations are also key contributors, it is important to know that there is underlying risk in the family genetic architecture itself."

Gauging the collective impact on autism risk of variations in the genetic code shared by most people, individually much subtler in effect, has proven to be even more challenging. Limitations in sample size and composition have made it difficult to detect these effects and to estimate the relative influence of such common, rare inherited and rare, spontaneous de novo variation. Differences in methods and statistical models have also resulted in estimates of autism heritability ranging from 17 to 50 percent.

Meanwhile, recent genome-wide studies of schizophrenia have achieved large enough sample sizes to reveal involvement of well over 100 common gene variants in that disorder. These promise improved understanding of the underlying biology – and even development of risk-scores, which could help predict who might benefit from early interventions to nip psychotic episodes in the bud.

With their new study, autism genetics is beginning to catch up, say the researchers. The PAGES study was made possible by Sweden's universal health registry, which allowed investigators to compare very large samples (n~3000 in the current study) of people with autism with matched controls.

Researchers also employed new statistical methods that allowed them to more reliably sort out the heritability of the disorder. In addition, they were able to compare their results with a parallel family-based study in the Swedish population, which took into account data from twins, cousins and factors such as age of the father at birth and parents' psychiatric history.

"This is a different kind of analysis than employed in previous studies," says Thomas Lehner, PhD, Chief of the National Institute of Mental Health's (NIMH) Genomics Research Branch. "Data from genome-wide association studies was used to identify a genetic model instead of focusing on just pinpointing genetic risk factors. The researchers were able to pick from all cases of illness within a population-based registry."

Now that the genetic architecture is better understood, the researchers are identifying specific genetic risk factors detected in the sample, such as deletions and duplications in genetic material and spontaneous mutations. Even though such rare spontaneous mutations accounted for only a small fraction of autism risk, the potentially large effects of these glitches makes them important clues to understanding the molecular underpinnings of the disorder, say the researchers.

"Within a given family, a de novo mutation could be a critical determinant that leads to the manifestation of autism spectrum disorder in a particular family member," says Dr. Buxbaum. "If the family has a common variation that puts it at risk, an added de novo mutation could push an individual over the edge and result in that person developing the disorder."

###

This study was supported by NIMH Grants MH057881 and MH097849, in part by the Seaver Foundation and through the computational resources and staff expertise provided by the Scientific Computing Facility at the Icahn School of Medicine at Mount Sinai.

Researchers from Carnegie Mellon University, the University of Pittsburgh School of Medicine, the University of California, San Francisco, Yale University School of Medicine, Massachusetts General Hospital and the Karolinska Institute in Stockholm, Sweden contributed to the study.

About the Seaver Autism Center for Research and Treatment at Mount Sinai:

The Seaver Autism Center for Research and Treatment at Mount Sinai conducts progressive research studies aimed at understanding the multiple causes of autism spectrum disorders (ASD). The multidisciplinary team is comprised of experts in the fields of genetics, molecular biology, model systems, neuroimaging, and experimental therapeutics who are dedicated to discovering the biological causes of ASD. The Center strives to develop innovative diagnostics and treatments for integration into the provision of personalized, comprehensive assessment and care for people with ASD. The Seaver Autism Center was founded through the generous support of the Beatrice and Samuel A. Seaver Foundation. For more information, visit http://www.seaverautismcenter.org.

About the Mount Sinai Health System

The Mount Sinai Health System is an integrated health system committed to providing distinguished care, conducting transformative research, and advancing biomedical education. Structured around seven member hospital campuses and a single medical school, the Health System has an extensive ambulatory network and a range of inpatient and outpatient services—from community‐based facilities to tertiary and quaternary care.

The System includes approximately 6,600 primary and specialty care physicians, 12‐minority‐owned free‐standing ambulatory surgery centers, over 45 ambulatory practices throughout the five boroughs of New York City, Westchester, and Long Island, as well as 31 affiliated community health centers. Physicians are affiliated with the Icahn School of Medicine at Mount Sinai, which is ranked among the top 20 medical schools both in National Institutes of Health funding and by U.S. News & World Report.

For more information, visit http://www.mountsinai.org, or find Mount Sinai on Facebook, Twitter and YouTube.

Elizabeth Dowling | Eurek Alert!

Further reports about: autism genetics research disorder mutations

More articles from Life Sciences:

nachricht How to become a T follicular helper cell
31.07.2015 | La Jolla Institute for Allergy and Immunology

nachricht Heating and cooling with light leads to ultrafast DNA diagnostics
31.07.2015 | University of California - Berkeley

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Tool making and additive technology exhibition: Fraunhofer IPT at Formnext

31.07.2015 | Trade Fair News

First Siemens-built Thameslink train arrives in London

31.07.2015 | Transportation and Logistics

California 'rain debt' equal to average full year of precipitation

31.07.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>