Bipolar disorder — like many other mental illnesses — is highly heritable. In other words, it runs in families. People who have first-degree relatives with bipolar disorder (that’s mothers, fathers, or siblings) are four to six times more likely to develop the illness than the rest of the population.
Because bipolar disorder appears to be genetic, scientists have been on the hunt for genes that may predispose individuals to the illness. Researchers have identified numerous genes already, but the human genome is complex and varied. Every day, researchers learn more and more about how genes function and what happens to them when things go wrong.
A new genetic variant discovered
A group of researchers at Karolinska Institutet, and the Sahlgrenska Academy at Gothenburg University in Sweden have identified a genetic variant that may contribute to both psychosis and cognitive impairment in individuals with bipolar disorder. The discovery of this gene could revolutionize treatment for bipolar disorder.
In this study, the researchers examined a group of people who were struggling with bipolar disorder in Stockholm and Gothenburg. First, the researchers carefully mapped out each patient’s specific symptoms. The researchers then had the patients perform a series of tests designed to measure cognitive impairments. Cognitive impairments associated with bipolar disorder often include difficulties concentrating, forgetfulness and all-around blurry thoughts. (Although cognitive impairments aren’t as well recognized as some of the other symptoms that accompany the illness, they are nonetheless present and can significantly impact an individual’s quality of life.)
After the scientists reviewed each patient’s symptoms and cognitive impairments, they then took a sample of their blood and cerebral spinal fluid (CSF), a substance that surrounds the brain. The researchers then used these fluid samples to perform a genome-wide association study (GWAS) and look for genes that correlated with either bipolar symptoms or cognitive impairments.
From this analysis, the researchers found that a genetic variant of the SNX7 gene was associated with CSF levels of a specific protein known as kynurenic acid as well as cognitive impairments and psychotic symptoms in bipolar disorder. In other words, this genetic variant may be at least partially responsible for the symptoms.
What does this mean?
Of course, this genetic variant is only one example of how individuals with bipolar disorder differ from neurotypical individuals. Researchers hope, however, that having this knowledge may assist the development of new, targeted treatments with fewer side effects and greater efficacy. Only the future knows whether this study will revolutionize treatment or serve as a mere blip in the radar. All we can do is wait.
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Written by Courtney Lopresti, M.S. neuroscience, Sovereign Health Group writer