64 genomic regions increase bipolar susceptibility

Researchers from over 200 institutions, including Neuroscience Research Australia (NeuRA), have conducted what is claimed to be the largest study ever to examine genetic risk factors for bipolar disorder. The researchers studied over 7.5 million common variations in the DNA sequence from almost 415,000 people, over 40,000 of whom had bipolar disorder, and identified 64 genomic regions that make people more susceptible to the disorder.

Bipolar disorder is a common mood disorder that affects around 350,000 Australians and an estimated 40 to 50 million people worldwide. The disorder usually develops during adolescence or early adulthood and can cause extreme manic and depressive symptoms, as well as psychosis. On average, people with bipolar disorder die 8–12 years earlier than the general population and are 20–30 times more likely to attempt suicide.

Until now, only a fraction of the genetic etiology of bipolar disorder had been identified. The new study, conducted by the Psychiatric Genomics Consortium and published in the journal Nature Genetics, revealed where in DNA the genetic variations that increase risk to bipolar disorder are located and what specific genes and pathways they impact, opening up future opportunities to better identify people who are likely to develop the condition and develop better treatments.

“Your genome is a book made up of letters, sentences and paragraphs that tell part of your personal story,” explained Associate Professor Fullerton, a senior research scientist at NeuRA. “This study is looking at common spelling mistakes that can change the meaning of the story, and occur more frequently in people with bipolar disorder. If a person’s genome has enough spelling mistakes, then this can result in bipolar disorder.”

Assoc Prof Fullerton said that by more clearly identifying the genetic signatures that are associated with bipolar disorder, the study creates opportunities for future research aimed at prediction and prevention of bipolar symptoms. Results from the study have also revealed the biological pathways that are impacted in bipolar disorder, which may lead to the development of more targeted, personalised medications.

“If we can identify the genetic risk factors for bipolar, we are more able to understand the biology of the disorder and, with hope, better treat it,” she said.

Researchers at NeuRA will now use these results to inform their ongoing Kids and Sibs study, conducted in collaboration with UNSW, which includes children and siblings of bipolar patients who are at high risk of developing bipolar disorder themselves. The aim of this research is to enable early identification of those young people on the trajectory towards illness who would most benefit from treatment to prevent the development of symptoms, and to reduce illness burden.

Image credit: ©stock.adobe.com/au/Benjavisa Ruangvaree

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