Largest genetic study offers new insights
A new study, the largest of its kind, finds more evidence of the genetic basis of schizophrenia. The results could ultimately lead to the development of new drugs.
The new study appears in the journal
Elliott Rees, a researcher at the Medical Research Council (MRC) Center for Neuropsychiatric Genetics and Genomics at Cardiff University in the UK, is the first author of the article.
As Rees and colleagues explain, common and rare risky genetic variants contribute to the development of schizophrenia.
However, scientists have found few of these variants, or alleles – common or rare – in existing genome-wide association studies.
Thus, researchers set out to discover rarer genetic variants involved in schizophrenia.
With that goal in mind, the team performed exome sequencing – a cutting-edge technique that enables rapid sequencing of large chunks of DNA – on 613 genetic trios of schizophrenia. A genetic trio refers to two parents and a child.
The team looked at the de novo variants in this sample of trios – in other words, they looked at new genetic variations in the offspring from the genes of both parents.
Then the researchers combined that data with existing information from 2,831 genetic trios (including 617 that Rees and his colleagues had analyzed in previous research), resulting in a total of 3,444 trios.
According to the authors, this provided “the greatest coding analysis [de novo variants] in schizophrenia to date.
Additionally, scientists focused on the overlapping high-risk genes between schizophrenia, autism spectrum disorders (ASD) and neurodevelopmental disorders.
The team found that a gene called SLC6A1 had much higher de novo mutation rates than expected.
Mutated genes were rare in that only about 3 in 3,000 people with schizophrenia had them.
However, the results are significant not because of the frequency of the mutations, but because they affect GABA, a major chemical neurotransmitter that is essential for the central nervous system.
The findings support previous research, which suggested that disturbances in neuronal GABAergic signaling are implicated in the genetic risk of schizophrenia.
“This work improves our understanding of the biological causes of this disease, which we hope will lead to the development of new and more effective treatments, as the identification of the key genes involved provides molecular targets for the development of new drugs.” , explains Rees.
“Developing new therapies can take many years, but it potentially brings us a little closer,” he adds.
The mutations the team found appear to increase genetic risk significantly, increasing the impact of the results and the therapeutic interventions that may result.
Study co-authored professor Sir Michael Owen, former director of the MRC Center, also comments on the results.
He says: “In addition to implicating a specific gene, SLC6A1, for the first time in schizophrenia, our results suggest that new mutations in genes important in brain development may be a major factor in some cases and that these mutations can also increase. the risk of other disorders such as autism and developmental delay.
“In addition to understanding how mutations impact brain function, it will be important to understand which factors modify their effects, as these may also be possible targets for new treatments. “
Overall, schizophrenia affects approximately
In the United States, estimates suggest that about 1.5 million people are living with the disease.