Genetic study provides insight into schizophrenia
31 July 2008
An international consortium of researchers has identified a number of genetic variations that may play a role in schizophrenia.
Schizophrenia is a common brain disorder characterized by delusions, hallucinations, and changes in motivation and behaviour. It affects approximately 1 person in 100 at some point in their lives, usually in late adolescence or early adulthood.
The research findings, reported in Nature and Nature Genetics, show that DNA variants common in the population also contribute to some individuals developing schizophrenia. The research was partly funded by the Medical Research Council and the Wellcome trust.
The researchers believe the risk genes, may offer advantages in brain function of unaffected people, which is why they can be found in the population at large.
Among the genes reported, a variant close to a gene called ZNF804A, appears to act by switching other genes on and off.
Professor O’Donovan of Cardiff University School of Medicine who led part of the consortium said:
“We looked for common changes in the genetic code that were more frequent in people with schizophrenia than people without it. Among the genes we found, the evidence for ZNF804A was particularly strong. We now need to determine the identity of the genes that it can switch on and off. Finding out which ones are regulated should tell us a lot about what biochemical disturbances result in disease, and provide further vital clues into the origins of schizophrenia and hopefully, new ways of treating it.”
The group also found that the same gene, ZNF804A also influences risk of bipolar disorder, also known as manic-depression.
The group’s results are one of three breakthrough findings in schizophrenia research reported in the journals Nature, and Nature Genetics.
The Nature paper describes the findings of The International Schizophrenia Consortium. Scientists found that people with schizophrenia are more likely to have an excess of rare deletions and duplications of large segments of genetic material across their entire genome. Two rare deletions, one on chromosome 1 and another on chromosome 15, found in around one percent of people with schizophrenia were identified.
Dr Pamela Sklar from Massachusetts General Hospital, Boston, who is part of the International Schizophrenia Consortium, said the findings give hope to people with schizophrenia as well as their friends and family.
"Of course, this is really the beginning and so much more needs to be done to understand how [these variants] produce disease," said Dr Sklar. "We've only explained a tiny fraction of why people might develop schizophrenia and much more work needs to be done to connect specific changes to the full spectrum of other types of genetic factors that might influence schizophrenia as well as the way in which those might interact with the environment."
Original research papers: The International Schizophrenia Consortium. Rare chromosomal deletions and duplications increase risk of schizophrenia, is published in Nature.
Large recurrent microdeletions associated with schizophrenia is published in Nature.
Identification of loci associated with schizophrenia by genomewide association and follow-up is published in Nature Genetics.
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