'It is now clear that the DISC1 gene plays an important role in the risk of developing schizophrenia or bipolar affective disorder. The new genetic link we have made to PDE4B and how that links back to DISC1 sheds much needed light on these debilitating disorders.'

Researchers from the Universities of Edinburgh and Glasgow, together with scientists from the pharmaceutical company Merck, Sharp & Dohme Limited, collaborated on work that led to their discovery of the second gene, phosphodiesterase 4B (PDE4B). The finding could lead to the eventual development of new drugs to treat mental health problems.

In 2000, researchers at the University of Edinburgh identified a gene they called Disrupted in Schizophrenia 1 (DISC1), which was found to increase the chances of people developing schizophrenia, bipolar disorder (manic depression) and major clinical depression.

The new research reveals that damage to the gene PDE4B also increases the risk of developing mental illness. PDE4B already was known to play an important role in how the brain thinks and builds memories, but had not been linked to mental disorder prior to this study. In addition, researchers have discovered that DISC1 acts as a regulator for PDE4B, creating a "pathway" between the two genes.

'Another Important Breakthrough'

"This is another important breakthrough in our still limited understanding of major mental illness," says Professor David Porteous at the University of Edinburgh.

"It is the result of a long-term research commitment to use the tools of genetics to better understand the root causes of mental disorder," he notes.

"It is now clear that the DISC1 gene plays an important role in the risk of developing schizophrenia or bipolar affective disorder. The new genetic link we have made to PDE4B and how that links back to DISC1 sheds much needed light on these debilitating disorders. It also suggests a new way of thinking about developing better and effective medicines," Professor Porteous explains.

May Lead to New Treatments for Schizophrenia

"Over the past few years we've been working hard to help in the development of medicines for treating asthma and chronic obstructive pulmonary disease by inhibiting very similar enzymes to PDE4B," says Professor Miles Houslay of the University of Glasgow.

"This new research has the potential for developing novel ways of diagnosing and treating this debilitating disease," he adds.

"Mental illness remains a scourge of society," says Peter Hutson, the Neuroscience Research Centre, Merck Sharp & Dohme. "Our insights into the important role that the proteins PDE4B and DISC1 may play in the misfunction of the brain that leads to schizophrenia will lead our thinking in the development of new treatments for this disorder."