Scottish researchers have identified another gene involved in schizophrenia and bipolar disorder (manic depression), a discovery that could lead to new drug treatments for the conditions. The team, based at the Universities of Edinburgh and Glasgow, has shown that an altered version of a gene called PDE4B is linked to an increased risk of mental illness. The findings, published in the journal Science, build on previous work on another gene implicated in schizophrenia.
In 2000, researchers at the University of Edinburgh identified the 'disrupted in schizophrenia' 1 (DISC1) gene, after studying a Scottish family with several members affected by the disorder. Further work linked an altered version of the gene to an affected American family, and it has also been implicated in bipolar disorder and major depression.
The latest study shows that the phosphodiesterase 4B (PDE4B) gene is also involved in major mental illness, and that the PDE4B protein interacts with the DISC1 protein. The team showed that the PDE4B gene was disrupted by a chromosome translocation (a chromosome alteration in which sections of two different chromosomes swap locations), which had been inherited by a person with schizophrenia, as well as a cousin who also had a psychotic disorder. PDE4B is known to play an important role in how the brain thinks and builds memories.
Team leader David Porteous said the study was 'another important breakthrough in our still limited understanding of major mental illness', adding 'it is the result of a long term research commitment to use the tools of genetics to better understand the root cause of mental illness'. Professor Porteous said the work suggested new approaches for developing medicines, but cautioned that 'risk isn't all controlled by genes. It's very much an interaction between genes and environmental factors'. In an accompanying commentary, Akira Sawa and Solomon Snyder also suggest that drugs which act on DISC1 and PDE4B could prove effective, but conclude that 'the prediction of drug effects is still highly speculative'.