‘An Ideal Marker’
Use of polygenetic risk scores reduces the possibility of reverse causation, noted Dr. Kowalec. “These markers are fixed at birth and don’t change over your lifespan, so they’re really an ideal marker.”
The results suggest polygenetic risk scores represent a potential biomarker for risk stratification in people with MS, said Dr. Kowalec. Although depression polygenic risk scores are not currently available in clinical practice, “I would hope this would change in the next 3-4 years,” she said.
Asked by a delegate if confounding by a third variable is possible, Dr. Kowalec said because genetic markers don’t change over time, there is a hint that the direction is causal and that depression is driving the outcome. However, she added, further confirmation is needed.
Dr. Kowalec noted that there were no data on antidepressant use but noted that about half of the Canadian and US cohorts — and likely the same number in the Swedish cohorts — self-reported depression.
A limitation of the study was that it included only participants of European ancestry.
Clinical Implications Unclear
Commenting on the research, Lauren Gluck, MD, program director, Montefiore Multiple Sclerosis Center, Bronx, New York, described the study as “fascinating” but noted that it’s unclear how to use this new information in clinical practice.
“Clinicians frequently ask people with MS about mood symptoms and offer interventions like antidepressants and referrals to therapists. However, genetic testing is not routine, so we don’t yet know who to target based on these data.”
Preexisting depression or more severe depression could be viewed as a “red flag” for risk for more disease activity in the future, she said.
“This could encourage clinicians to use more highly effective therapy in these patients, similar to our strategies for people with MS with frequent attacks and more disease burden on MRIs.”
The study received support from the Consortium of Multiple Sclerosis Centers and the Congressionally Directed Medical Research Programs, Department of Defense.
Dr. Kowalec reported no relevant conflicts of interest.
A version of this article appeared on Medscape.com.