Previous studies have shown that the risk of developing manic depression, or bipolar disorder as it is sometimes known, is largely down to genetic factors. But scientists have been unable to pin down exactly which genes are involved, and so we do not know very much about the mechanisms of the illness.
Study on 50,000 people
An international study of more than 50,000 people has now identified one gene in particular that is linked to a calcium channel in the brain and is thought to play a key role in the development of bipolar disorder. Recently published in the revered journal Nature Genetics, the study involved researchers from the Sahlgrenska Academy at the University of Gothenburg and is opening up new targets for future treatments.
Dramatic developments in the technology for analysing genetic variation between individuals during recent years have meant that the focus of research has shifted away from studies of individual genes and towards analyses of all our genetic material, the entire genome.
Interaction between genes
One of the leading collaborations for this kind of genome study in the field of bipolar disorder is the Psychiatric GWAS Consortium (PGC), which involves researchers from Sweden, Europe and the USA. In its most recent study the consortium analysed 11,974 people with bipolar disorder and compared them with 42,422 controls. The results back up previous studies which show that bipolar disorder is down to the interaction between many genes, each of which has only a minor effect on its own, but the researchers have also identified a specific gene that is believed to have a particularly strong link to the disorder.
Encourages further research
“The gene, known as CACNA1C, codes for a calcium channel in the brain,” says Mikael Landén, the researcher at the Sahlgrenska Academy who heads up the University of Gothenburg’s work on the international project. “This is interesting because some drugs for bipolar disorder act on this very channel. It will also encourage further research into how the calcium channel affects the disorder.”
Landén believes that the results confirm the benefits of gathering and studying large volumes of patient material.
“The fact is that we’ll be needing even more material if we are to gain a better understanding of bipolar disorder, and this is an area where Sweden can make a valuable contribution.”
The article, Large-scale genome-wide association analysis of bipolar disorder identifies a new susceptibility locus near ODZ4, was published in Nature Genetics on 18 September.
Link to the article: http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.943.html
Mikael Landén, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg