A previously unknown genetic pathway for developing anxiety disorders has been pinpointed by a research team from Julius-Maximilians-Universität Würzburg (JMU) in Germany. They identified at least four variants of the glycine receptor B gene (GLRB) as risk factors for anxiety and panic disorders.
The study involved more than 5000 voluntary participants and 500 patients afflicted by panic disorder.
Anxiety disorders are the most common mental illness in the U.S., affecting 40 million adults in the United States age 18 and older, or 18% of the population, according to the National Institute of Mental Health. Anxiety and panic disorders develop from a complex set of risk factors, including genetics, brain chemistry, personality, and life events.
Some people suffering from an anxiety disorder may have an extreme fear of spiders or other objects while others have breathing difficulties and accelerated heart beat in small rooms or large gatherings of people. With some afflicted persons, panic attacks occur for no apparent cause.
Many patients suffer from the detrimental impacts on their everyday lives, often having problems at work and withdrawing from social contacts. The discovery that different variants of the GLRB gene are associated with anxiety disorders may contribute to the development of improved therapies. The gene had been known to the researchers for some time, albeit only in connection with a different disease.
“Some mutations of the gene cause a rare neurological disorder called hyperekplexia,"
explains Professor Jürgen Deckert, member of the CRC and Director of the Department of Psychiatry at the JMU University Hospital. The patients are permanently hypertonic and show pronounced startle responses, which may even cause sufferers to fall involuntarily.
Similar to persons suffering from anxiety disorders, these patients develop behavior to avoid potentially frightening situations.
GLRB Anxiety Gene Variants
But the GLRB gene variants that have recently been associated with anxiety and panic disorders for the first time are different from the ones described above. They occur more frequently and presumably entail less severe consequences.
But they, too, trigger overshooting startle responses, and as a result may excessively activate the brain’s “fear network”. High-resolution images of the brain activities of study participants provided the clues for the Würzburg scientists.
“The results point to a hitherto unknown pathway of developing an anxiety disorder,” Deckert says.
He believes that further investigations are now necessary to determine whether these findings can be harnessed to develop new or individual therapies. For example, it is conceivable to bring the “fear network” that is misregulated by the GLRB gene back on track by administering drugs.
J Deckert, et al GLRB allelic variation associated with agoraphobic cognitions, increased startle response and fear network activation: a potential neurogenetic pathway to panic disorder Molecular Psychiatry , (7 February 2017) | doi:10.1038/mp.2017.2
Image: Dr. Tina Lonsdorf, Systems Neuroscience UKE Hamburg