Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Distinct brain disorders biologically linked

05.08.2013
Disruption to the gene TOP3B increases susceptibility to schizophrenia and a learning disorder

A team of researchers have shown that schizophrenia and a disorder associated with autism and learning difficulties share a common biological pathway. This is one of the first times that researchers have uncovered genetic evidence for the underlying causes of schizophrenia.



The team found that a disruption of the gene TOP3B, an exceedingly rare occurrence in most parts of the world, is fairly common in a uniquely genetically distinct founder population from North-eastern Finland. In this population, which has grown in relative isolation for several centuries, the disruption of TOP3B is associated with an increased risk of schizophrenia as well as with impairment in intellectual function and learning.

Furthermore, the biochemical investigation of the protein encoded by the TOP3B gene allowed the researchers to gain first insight into the cellular processes that might be disturbed in the affected individuals.

Although the past two decades have revealed a wealth of information about the genetics of disease, we still know little about the biology behind schizophrenia. Many associations between schizophrenia and genetic risk factors have been reported, but only a very few can be considered schizophrenia susceptibility genes. This study uncovers an important biological pathway that appears to underlie schizophrenia and could contribute to the cognitive impairment that is an important component of this disorder.

"This is a tremendous discovery for our team; not only have we uncovered vital information about the biology behind schizophrenia, but we have also linked this same biological process to a disorder associated with learning difficulties," says Dr Aarno Palotie, lead author from the Wellcome Trust Sanger Institute, the Broad Institute of MIT and Harvard and the Institute for Molecular Medicine Finland. "Our findings offer great hope for future studies into the genetic basis of schizophrenia and other brain disorders, potentially finding new drug targets against them."

The North-eastern population of Finland has three times the frequency of schizophrenia compared to the national average in Finland, as well as a higher rate of intellectual impairment and learning difficulties. The team used data collected from this unique population to sift through genomic data for genetic deletions that may influence people's susceptibility to schizophrenia.

The team identified a rare genetic deletion affecting TOP3B in the North-eastern Finnish population that increases a person's susceptibility to schizophrenia two-fold and that also is associated with an increased frequency of other disorders of brain development such as intellectual impairment. They speculate that this deletion directly disrupts the TOP3B gene to cause its effects on the brain.

Having identified the link between TOP3B and schizophrenia, the researchers sought to understand why disrupting this gene might increase susceptibility to disease, and for this purpose they investigated the function of the protein that it encodes.

"Such an approach is only possible when researchers from different disciplines – in our case geneticists and biochemists team up," says Professor Utz Fischer, author from the University of Wurzburg. "Luckily, when we teamed up with the genetic team we had already worked on the TOP3B gene product for more than 10 years and hence had a good idea what this protein is doing".

TOP3B encodes a type of protein that typically helps the cell to unwind and wind DNA helices – essential to normal cell function. Quite unexpectedly for an enzyme of this class, however, TOP3B was found to act on messenger-RNA rather than DNA.

In their further biochemical investigation into TOP3B, the team found that the TOP3B protein interacts with a protein known as FMRP. The deactivation or disruption of this protein is responsible for Fragile X syndrome, a disorder associated with autism and learning difficulties, primarily in men.

Within the northern Finnish population, the team identified four people who did not have a functioning copy of the TOP3B gene. These four people were either diagnosed as having learning difficulties or as having schizophrenia, solidifying the evidence that this gene is important in these brain disorders and that they are biologically linked.

"These two disorders, schizophrenia and Fragile X syndrome, although they may seem drastically different, share key features, particularly the cognitive impairment that is frequently associated with both conditions," says Dr Nelson Freimer, author from UCLA. "So, it is not unexpected that they could share some of the same biological processes.

"What is fantastic about this study is that through investigations in an isolated corner of Finland we are contributing to concerted international efforts that are beginning to unravel the genetic root of schizophrenia, a debilitating disorder that affects so many people throughout the world."

Publication Details

Georg Stoll, Olli P H Pietiläinen, Bastian Linder, Jaana Suvisaari, Cornelia Brosi, William Hennah, Virpi Leppä, Minna Torniainen, Samuli Ripatti, Sirpa Ala-Mello, Oliver Plöttner, Karola Rehnström, Annamari Tuulio-Henriksson, Teppo Varilo, Jonna Tallila, Kati Kristiansson, Matti Isohanni, Jaakko Kaprio, Johan G Eriksson, Olli T Raitakari, Terho Lehtimäki, Marjo-Riitta Jarvelin, Veikko Salomaa, Matthew Hurles, Hreinn Stefansson, Leena Peltonen, Patrick F Sullivan, Tiina Paunio, Jouko Lönnqvist, Mark J Daly, Utz Fischer1, Nelson B Freimer & Aarno Palotie. (2013) 'Deletion of TOP3b, a component of FMRP-containing mRNPs, contributes to neurodevelopmental disorders' Advanced online publication in Nature Neuroscience on 04 August. doi:10.1038/nn.3484

Funding

A full list of funding can be found on the paper

Participating Centres
Department of Biochemistry, University of Würzburg, Würzburg, Germany.
Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.
Institute for Molecular
Medicine Finland, Helsinki, Finland.
National Institute for Health and Welfare, Public Health Genomics Unit, Helsinki, Finland.
National Institute for Health and Welfare, Department of Mental Health and Substance Abuse Services, Helsinki, Finland.
Helsinki University Central Hospital, Department of Clinical Genetics, Helsinki, Finland. Pharma Research and Early Development, Roche Diagnostics GmbH, Penzberg, Germany.
Department of Psychiatry, Institute of Clinical Medicine, University of Oulu, Oulu, Finland.
Department of Public Health, University of Helsinki, Helsinki, Finland.
National Institute for Health and Welfare, Chronic Disease Epidemiology and Prevention, Helsinki, Finland.
Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland.
Vaasa Central Hospital, Vaasa, Finland.
Folkhälsan Research Centre, Helsinki, Finland.
Unit of General Practice, Helsinki University Central Hospital, Helsinki, Finland.
Department of Clinical Physiology and Nuclear Medicine, University of Turku and Turku University Hospital, Turku, Finland.
Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku and Turku University Central Hospital, Turku, Finland.
Department of Clinical Chemistry, University of Tampere and Tampere University Hospital, Tampere, Finland.
Department of Epidemiology and Biostatistics, Imperial College London, London, UK.
MRC-HPA Centre for Environment and Health, Imperial College London, London, UK.
National Institute of Health and Welfare, Oulu, Finland.
Institute of Health Sciences, University of Oulu, Oulu, Finland.
National Institute for Health and Welfare, Department of Chronic Disease Prevention, Helsinki/Turku, Finland.
deCODE genetics, Reykjavik, Iceland.
Department of Medical Genetics, University of Helsinki, Helsinki, Finland.
Deceased.
Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Department of Psychiatry and Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
University of Helsinki and Helsinki University Central Hospital, Department of Psychiatry, Helsinki, Finland.
Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.
Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.

Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California, USA.

Selected Websites

The Wellcome Trust Sanger Institute is one of the world's leading genome centres. Through its ability to conduct research at scale, it is able to engage in bold and long-term exploratory projects that are designed to influence and empower medical science globally. Institute research findings, generated through its own research programmes and through its leading role in international consortia, are being used to develop new diagnostics and treatments for human disease. http://www.sanger.ac.uk

The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. We support the brightest minds in biomedical research and the medical humanities. Our breadth of support includes public engagement, education and the application of research to improve health. We are independent of both political and commercial interests. http://www.wellcome.ac.uk

Contact details

Don Powell Media Manager
Wellcome Trust Sanger Institute
Hinxton, Cambridge, CB10 1SA, UK
Tel +44 (0)1223 496 928
Mobile +44 (0)7753 7753 97
Email press.office@sanger.ac.uk

Aileen Sheehy | EurekAlert!
Further information:
http://www.sanger.ac.uk

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Desert ants cannot be fooled

23.11.2017 | Life Sciences

By saving cost and energy, the lighting revolution may increase light pollution

23.11.2017 | Earth Sciences

Retreating permafrost coasts threaten the fragile Arctic environment

23.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>