Schizophrenia is a severe and chronic psychiatric disorder affecting one percent of the global population. It is characterized by delusions, hallucinations, abnormal movements and impaired social behavior. Schizophrenia’s genetic links have long been suspected, but a new study reveals that its link to the human genome goes far deeper than originally thought.
Specifically, a multinational group of genetic researchers recently discovered 83 new gene variants that likely play a role in the development of schizophrenia. Their study significantly brings the known total – from 30 to 108 – the number of chromosomal sites that are linked to the brain disorder.
In the study conducted by the Schizophrenia Working Group of the Psychiatric Genomics Consortium (PGC), 500 researchers from 25 countries studied complete genome profiles of 37,000 people diagnosed with schizophrenia, along with 113,000 others who did not have the disease. The sample size makes the study the largest ever to be done for a psychiatric disorder.
The researchers found out that the 83 newly found gene variants were not randomly scattered, but instead were clustered around pathways related to certain processes, such as memory, learning, immune function, communication between brain cells, and targets to medication. They also found the genes to be expressed in particular cell types and tissues. The researchers also noted a strong link between the immune system and schizophrenia. This means that future researchers can look at these pathways, study the immune response, and then formulate new targeted therapies that can treat the condition.
These new therapies could include newer drugs. Treatment options for schizophrenia have been limited partly because researchers have not understood the complexity of the genetic basis of the condition. Of note, there has not been a true breakthrough drug to treat patients in more than half a century. The project seeks to herald new treatments.
“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,” Michael O’Donovan, senior author of the study and deputy director of the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University School of Medicine, told Forbes. “The wealth of new findings have the potential to kick-start the development of new treatments in schizophrenia, a process which has stalled for the last 60 years.”
The study can also help experts make more accurate screening programs, according to an official of the National Institute of Health, which provided the core funding for the research project.
“While the suspect variation identified so far only explains about 3.5 percent of the risk for schizophrenia, these results warrant exploring whether using such data to calculate an individual’s risk for developing the disorder might someday be useful in screening for preventive interventions,” Thomas R. Insel, M.D., director of the NIH’s National Institute of Mental Health, said in a statement.
Insel said that with the expanded list of gene markers, “people who score in the top 10% of risk may be up to 20-fold more prone to developing schizophrenia.”
The landmark study was published recently in the journal Nature. The PGC researchers are still mapping the genes of hundreds of thousands of people to increase the sample size and to hopefully find more genes linked to other mental conditions.
“By studying the genome, we are getting a better handle on the genetic variations that are making people vulnerable to psychiatric disease,” Insel told the Harvard Gazette. “Through the wonders of genomic technology, we are in a period in which, for the first time, we are beginning to understand many of the players at the molecular and cellular level.”
It is likely that institutional genomics research done by the PGC and others develops along with personal genomics, as more people want to find out for themselves directly their risk for developing schizophrenia, or any other disease with a genetic connection.