A new line of research suggests that genetic mutations associated with blood cancers may also play a role in triggering Alzheimer’s disease, by producing immune cells that become overactive and inflame brain tissue over time. The findings add a new dimension to the understanding of how the most common form of dementia develops and may eventually open unexpected paths toward prevention.

The mutations in question belong to a phenomenon called clonal hematopoiesis, in which a single mutated stem cell in the bone marrow begins producing a large proportion of a person’s blood cells. These mutations are increasingly common with age and are well established as risk factors for blood cancers including leukaemia and myeloma. The new research suggests they also produce microglia — the brain’s resident immune cells — that are in a chronically activated, inflammatory state.

When those microglia are overly active for sustained periods, they damage neurons and accelerate the accumulation of amyloid plaques and tau tangles that are the hallmarks of Alzheimer’s disease. The researchers found that people with these blood-cancer-linked mutations had meaningfully higher rates of Alzheimer’s diagnosis than people without them, even after controlling for age and other known risk factors.

The implication is that Alzheimer’s and certain blood conditions may share a common root in the bone marrow rather than developing through entirely separate pathways. If confirmed through further study, that connection could mean that monitoring for clonal hematopoiesis mutations — something increasingly done as part of cancer screening — might also serve as a risk indicator for dementia.

Alzheimer’s currently affects an estimated 55 million people worldwide, with the number expected to grow significantly as populations age. Treatments that target the disease’s progression have been approved in recent years, but catching the disease early enough for those treatments to be effective remains difficult. Better biomarkers and risk indicators are seen as one of the most important unmet needs in the field.

The research also raises questions about whether existing drugs used to manage blood cancer mutations might have secondary benefits for Alzheimer’s risk. Some agents used to suppress clonal hematopoiesis are already in clinical use, and researchers said the new findings provided a scientific rationale for exploring their effects on dementia risk in future trials.

Scientists cautioned that the findings, while compelling, represent a correlation rather than a proven causal mechanism. The next step involves experimental work in laboratory models to trace the pathway by which the bone marrow mutations produce inflammatory microglia and to test whether interrupting that pathway changes Alzheimer’s outcomes. Full clinical trials, if the early results hold, are likely still several years away. ScienceDaily noted that multiple research groups are now working along related lines, suggesting the connection between blood cell genetics and brain disease will be a major focus of neuroscience and oncology research in the coming years.