People with multiple sclerosis may face a higher risk of Alzheimer’s disease, according to new genetic analysis linking immune system changes to both conditions.
Researchers found that gene variants affecting immune T-cells—white blood cells that help fight infection—may play a role in the development of both MS and Alzheimer’s. MS is a condition where the immune system attacks healthy tissue in the brain and spinal cord, causing inflammation and damage.
A team in India used a method called Mendelian randomisation to investigate whether gene changes linked to MS also appear more frequently in people with Alzheimer’s. The technique can help identify whether one condition might contribute to the risk of another.
They identified 44 gene variants associated with MS risk that also showed links to Alzheimer’s. “These findings suggest that genetic predisposition to MS may increase the risk of developing [Alzheimer’s],” the researchers wrote.
Previous studies have shown people with MS are more likely than the general population to develop Alzheimer’s, but the biological connection remains unclear. Both diseases involve damage to the brain, and there is growing evidence that abnormal inflammation may contribute to Alzheimer’s, a form of dementia that causes cognitive decline.
The researchers found many of the overlapping genes were involved in the function of T-helper cells—a type of immune cell that helps coordinate the immune response by releasing chemical signals.
They suggested these genetic changes could underlie both MS and Alzheimer’s, pointing to a possible shared mechanism. “Taken together, these findings reinforce the notion of a causal effect of MS on [Alzheimer’s], particularly mediated by immune-regulatory mechanisms involving T-helper cell differentiation,” they wrote.
A key limitation was that the genetic data used in the study came from individuals of European descent. A similar analysis in a smaller dataset of African American participants did not produce statistically significant results. The team said the findings should be validated in more diverse populations.