Researchers zero in on triggers of schizophrenia
Mental illness could have autoimmune component
TORONTO — Little is known about the causes of schizophrenia, but an international consortium of researchers has made a significant discovery about its genetic underpinnings that should improve understanding of this devastating mental illness.
Scientists from around the world, including Canadians, have identified more than 100 locations in the human genome associated with the risk of developing schizophrenia, a brain disorder characterized by hallucinations, delusions and disordered thinking.
The research, published Tuesday in the journal Nature, pinpoints 83 newly discovered locations of genetic variations in the DNA of people with schizophrenia, bringing the number known to 108.
“It gives us a whole new avenue for research,” said Jo Knight, a senior scientist at the Centre for Addiction and Mental Health in Toronto, who was part of the research group.
“We’ve just been given a haystack and now we have to find all the needles. But we know they’re in there and we know now this is the haystack to be looking in,” she said Monday.
Those needles are genetic mutations that give rise to schizophrenia, which often emerges in the teens and early 20s and affects one in every 100 people worldwide. The price tag of health care, social costs and lost productivity resulting from the debilitating mental illness is estimated at $6.85 billion a year in Canada alone.
“It gives us a whole new avenue for research.”
JO KNIGHT
Knight said there are many theories as to why someone might be susceptible to developing schizophrenia, which is believed to be caused by a combination of many genes as well as environmental triggers.
The new findings implicate genes expressed in brain tissue, particularly those related to the functioning of neurons and the pathways that enable chemical and electrical signalling between these brain cells, known as synapses.
They also give weight to a theory that genes active in immune-system functioning may also be involved with schizophrenia, suggesting that it could be an autoimmune disease, at least in part.
“When you start getting at the genetic architecture, you start having much more of an understanding of the pathology,” said Knight. “And once you know why someone is becoming schizophrenic, you’re much more likely to be able to develop a drug to act on the mechanism or develop preventive measures that stop an individual following that route.”
The study follows several years of work by the Schizophrenia Working Group of the Psychiatric Genomics Consortium, an international collaboration founded in 2007 to conduct broad-scale analyses of genetic data for psychiatric disease.
In the study, the authors looked at almost 37,000 genetic samples from schizophrenia patients and about 113,000 healthy volunteers and found 108 specific locations in the human genome associated with the risk of schizophrenia.
“The fact that we were able to detect genetic risk factors on this massive scale shows that schizophrenia can be tackled by the same approaches that have already transformed our understanding of other diseases,” said senior study author Dr. Michael O’Donovan, deputy director of the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University School of Medicine.