Corporate Banner
Satellite Banner
Genomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Genetic Analysis Reveals Insights into Genetics of OCD, Tourette’s

Published: Tuesday, November 05, 2013
Last Updated: Tuesday, November 05, 2013
Bookmark and Share
Major differences between the genetic makeup of obsessive-compulsive disorder and Tourette’s syndrome, providing the first direct confirmation that both are highly heritable.

“Both TS and OCD appear to have a genetic architecture of many different genes—perhaps hundreds in each person—acting in concert to cause disease,” said Jeremiah Scharf, assistant professor of neurology at Harvard Medical School and senior corresponding author of the report. “By directly comparing and contrasting both disorders, we found that OCD heritability appears to be concentrated in particular chromosomes, particularly chromosome 15, while TS heritability is spread across many different chromosomes.”

An anxiety disorder characterized by obsessions and compulsions that disrupt the lives of patients, OCD is the fourth-most common psychiatric illness. TS is a chronic disorder characterized by motor and vocal tics that usually begins in childhood and is often accompanied by conditions like OCD or attention-deficit hyperactivity disorder. Both conditions have been considered to be heritable, since they are known to often recur in close relatives of affected individuals, but identifying specific genes that confer risk has been challenging.

Two reports published last year in the journal Molecular Psychiatry, with leadership from Scharf and several co-authors of the current study, described genome-wide association studies (GWAS) of thousands of affected individuals and controls. While those studies identified several gene variants that appeared to increase the risk of each disorder, none of the associations were strong enough to meet the strict standards of genome-wide significance. Since the GWAS approach is designed to identify relatively common gene variants and it has been proposed that OCD and TS might be influenced by a number of rare variants, the research team adopted a different method. Called genome-wide complex trait analysis (GCTA), the approach allows simultaneous comparison of genetic variation across the entire genome, rather than the GWAS method of testing sites one at a time, as well as estimating the proportion of disease heritability caused by rare and common variants.

“Trying to find a single causative gene for diseases with a complex genetic background is like looking for the proverbial needle in a haystack,” said Lea Davis, a UChicago research assistant professor and co-corresponding author of the PLOS Genetics report. “With this approach, we aren’t looking for individual genes. By examining the properties of all genes that could contribute to TS or OCD at once, we’re actually testing the whole haystack and asking where we’re more likely to find the needles.”

Using GCTA, the researchers analyzed the same genetic datasets screened in the Molecular Psychiatry reports—almost 1,500 individuals affected with OCD compared with more than 5,500 controls, and nearly TS 1,500 patients compared with more than 5,200 controls. To minimize variations that might result from slight difference in experimental techniques, all genotyping was done by collaborators at the Broad Institute of Harvard University and MIT, who generated the data at the same time using the same equipment. Davis was able to analyze the resulting data on a chromosome-by-chromosome basis, along with the frequency of the identified variants and the function of variants associated with each condition.

The results found that the degree of heritability for both disorders captured by GWAS variants is actually quite close to what previously was predicted based on studies of families impacted by the disorders. “This is a crucial point for genetic researchers, as there has been a lot of controversy in human genetics about what is called ‘missing heritability,’” explained Scharf. “For many diseases, definitive genome-wide significant variants account for only a minute fraction of overall heritability, raising questions about the validity of the approach. Our findings demonstrate that the vast majority of genetic susceptibility to TS and OCD can be discovered using GWAS methods. In fact, the degree of heritability captured by GWAS variants is higher for TS and OCD than for any other complex trait studied to date.”

Nancy Cox, section chief of Genetic Medicine at UChicago and co-senior author of the PLOS Genetics report, added, “Despite the fact that we confirm there is shared genetic liability between these two disorders, we also show there are notable differences in the types of genetic variants that contribute to risk. TS appears to derive about 20 percent of genetic susceptibility from rare variants, while OCD appears to derive all of its susceptibility from variants that are quite common, which is something that has not been seen before.”

In terms of the potential impact of the risk-associated variants, about half the risk for both disorders appears to be accounted for by variants already known to influence the expression of genes in the brain. Further investigation of those findings could lead to identification of the affected genes and how the expression changes contribute to the development of TS and OCD. Additional studies in even larger patient populations, some of which are in the planning stages, could identify the biologic pathways disrupted in the disorder, potentially leading to new therapeutic approaches.


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,400+ scientific posters on ePosters
  • More than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

New Form of DNA Modification May Carry Inheritable Information
Scientists have described the surprising discovery and function of a new DNA modification in insects, worms and algae.
Friday, May 08, 2015
Researchers Identify ‘Fat Gene’ Associated with Obesity
Mutations within the gene FTO have been implicated as the strongest genetic determinant of obesity risk in humans, but the mechanism behind this link remained unknown.
Monday, March 17, 2014
Humans and Chimps Share Genetic Strategy in Battle Against Pathogens
Findings point to common ancestry.
Tuesday, February 19, 2013
Graeme Bell Receives International Diabetes Prize
Prize includes a certificate of honor, a Japanese objet d’art and a $150,000 prize.
Tuesday, December 18, 2012
Study Points to New Target for Cancers Resistant to Certain Drugs
A more sensitive method to analyze protein interactions has uncovered a new way that cancer cells may use the cell-surface molecule HER3 to drive tumor progression following treatment with HER1 and HER2 inhibitors.
Tuesday, September 11, 2012
Grapefruit Juice Lets Patients Take Lower Dose of Cancer Drug
First cancer study to harness drug-food interaction.
Thursday, August 09, 2012
Guidelines for Prostate Screening Widely Ignored, Study Finds
2008 recommendations from federal task force had no impact.
Monday, April 30, 2012
Chicago Cancer Genome Project Studies Genetics of 1,000 Tumors
Analyzing the genetics of cancers from different parts of the body may reveal surprising details for treatment and prevention.
Tuesday, December 29, 2009
Metabolic Syndrome Linked to Cold Tolerance
Researchers discover that many of the genetic variations that have enabled human populations to tolerate colder climates may also affect their susceptibility to metabolic syndrome.
Monday, February 18, 2008
Mutations in the Insulin Gene can Cause Neonatal Diabetes
Mutations in the insulin gene can cause permanent neonatal diabetes that affects very young children and results in lifelong dependence on insulin injections.
Friday, September 14, 2007
Microfluidics Gives Boost to Protein Crystallization Studies
A team of investigators have developed a nanoliter microfluidic device that can conduct approximately 1,900 crystallization experiments per hour.
Friday, January 19, 2007
Scientific News
RNAi Screening Trends
Understand current trends and learn which application areas are expected to gain in popularity over the next few years.
The Genetic Roots of Adolescent Scoliosis
Scientists at the RIKEN Center for Integrative Medical Sciences in collaboration with Keio University in Japan have discovered a gene that is linked to susceptibility of Scoliosis.
A Gene-Sequence Swap Using CRISPR to Cure Haemophilia
For the first time chromosomal defects responsible for hemophilia have been corrected in patient-specific iPSCs using CRISPR-Cas9 nucleases
New Tool Uses 'Drug Spillover' to Match Cancer Patients with Treatments
Researchers have developed a new tool that improves the ability to match drugs to disease: the Kinase Addiction Ranker (KAR) predicts what genetics are truly driving the cancer in any population of cells and chooses the best "kinase inhibitor" to silence these dangerous genetic causes of disease.
Understanding the Molecular Origin of Epigenetic Markers
Researchers at IRB Barcelona discover the molecular mechanism that determines how epigenetic markers influence gene expression.
New Tech Enables Epigenomic Analysis with a Mere 100 Cells
A new technology that will dramatically enhance investigations of epigenomes, the machinery that turns on and off genes and a very prominent field of study in diseases such as stem cell differentiation, inflammation and cancer has been developed by researchers at Virginia Tech.
Access Denied: Leukemia Thwarted by Cutting Off Link to Environmental Support
A new study reveals a protein’s critical – and previously unknown -- role in the development and progression of acute myeloid leukemia (AML), a fast-growing and extremely difficult-to-treat blood cancer.
New Weapon in the Fight Against Blood Cancer
This strategy, which uses patients’ own immune cells, genetically engineered to target tumors, has shown significant success against multiple myeloma, a cancer of the plasma cells that is largely incurable.
Toxin from Salmonid Fish has Potential to Treat Cancer
Researchers from the University of Freiburg decode molecular mechanism of fish pathogen.
Study Finds Non-Genetic Cancer Mechanism
Cancer can be caused solely by protein imbalances within cells, a study of ovarian cancer has found.
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!