More than 100 genetic regions have been found to be involved in schizophrenia, many of which were not previously linked to the condition.
Researchers say the finding uncovers the biological mechanisms causing the severe psychiatric disorder, and could lead to new treatments being developed.
'We've been able to detect genetic risk factors on a huge and unprecedented scale and shed new light on the biological cause of the condition', said study leader Professor Michael O'Donovan, from Cardiff University's MRC Centre for Neuropsychiatric Genetics and Genomics. The large genome-wide association study was carried out by the Schizophrenia Working Group of the Psychiatric Genomics Consortium.
One hundred and eight locations (loci) in the human genome were linked to schizophrenia, 83 of which were previously unknown. The study, published in Nature, noted that many of the genes were expressed in the brain, thus 'providing biological plausibility for the findings'. Three-quarters of the loci coded for proteins, including the dopamine receptor (which most current schizophrenia medications target), as well other genes involved in brain signalling.
Some of the newly identified schizophrenia-linked genes were involved in immunity, specifically the memory cells that give us acquired immunity. The immune system had not previously been associated with the development of schizophrenia.
'Detecting biological risk factors on this scale shows that schizophrenia can be tackled by the same approaches that have already transformed outcomes for people with other diseases. We now believe they can also do so for schizophrenia which has, until now, been so poorly understood', says Professor Sir Michael Owen, director of the MRC Centre for Neuropsychiatric Genetics and Genomics.
Researchers have long known that a person's schizophrenia risk is influenced by their genes, because people whose parents or siblings are diagnosed with schizophrenia are more likely to be diagnosed themselves. Although genes are not the only factor in developing the disease, the study may provide important insights into how to develop new drugs and diagnostic tools. This is much needed as current treatments are not always effective.
'The key challenge now is to translate these new insights into the biological basis of schizophrenia, into new diagnostic tools and novel treatments for patients and finally put an end to the 60-year-wait for new treatments for sufferers worldwide', explained Professor O'Donovan.