44 genetic variants which are risk factors for depression have been mapped out by a global research project. 30 of these variants are newly discovered.
The project, a genome-wide association analysesw conducted by the Psychiatric Genomics Consortium and co-led in the UK by King’s College London, is the largest study yet of genetic risk factors for major depression.
A significant number of the genetic variants pinpointed in the study are directly linked to the targets of current antidepressant medications. Analysis of the data also suggests that having higher BMI is linked to an increased risk of major depression.
The genetic basis for major depression is shared with other psychiatric disorders such as schizophrenia, the research finds, and all humans carry at least some of the 44 genetic risk factors identified in the study.
Major Depressive Disorder
Around 14% of the world’s population is affected by major depression, but only about half of patients respond well to existing treatments.
“With this study, depression genetics has advanced to the forefront of genetic discovery. The new genetic variants discovered have the potential to revitalise depression treatment by opening up avenues for the discovery of new and improved therapies,"
says Dr. Gerome Breen from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London.
Previous studies have struggled to identify more than a handful of genetic variants associated with depression. By combining seven separate datasets, the research team included data on more than 135,000 people with major depression and more than 344,000 controls.
The study was an unprecedented global effort by over 200 scientists who work with the Psychiatric Genomics Consortium, and was led by the University of North Carolina School of Medicine and the University of Queensland in Australia. Professor Cathryn Lewis and Dr. Breen of King’s College London led the UK contribution, along with scientists and psychiatrists from the Universities of Edinburgh, Cardiff and UCL.
Only The First Step
The results do not help us understand how some of these genes affect depression. Not only that, but finding a single treatment that can target all these gene variants is fairly unlikely.
Nonetheless, the study is important. It adds more evidence to the hypothesis that depression has a genetic basis. It also demonstrates the usefulness of large-scale collaborations in investigating the genetic roots of psychiatric illnesses.
“This study has shed a bright light on the genetic basis of depression, but it is only the first step. We need further research to uncover more of the genetic underpinnings, and to understand how genetics and environmental stressors work together to increase risk of depression,"
said Professor Lewis.
Naomi R. Wray, Stephan Ripke, et al. Genome-wide association analyses identify 44 risk variants and refine the genetic architecture of major depression Nature Genetics (2018) doi:10.1038/s41588-018-0090-3
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