While some people develop heart disease and diabetes in their 50s, others remain disease-free well into their 80s and 90s. The difference, it turns out, may come down to rare mutations passed through families that dampen the body's inflammatory response without leaving it vulnerable to infection.
Researchers at Leiden University Medical Center have identified a variant in the CGAS gene that appears in families with exceptional longevity. The discovery emerged from studying 212 groups of siblings where both parents lived exceptionally long lives, a more targeted approach than the traditional focus on studying individual long-lived people.
The breakthrough hinges on a simple observation. Middle-aged adults whose parents both lived long lives developed serious cardiometabolic diseases roughly 13 years later than peers from average-lifespan families. This pattern suggested that longevity itself is heritable, not merely a matter of luck or lifestyle.
Using genome analysis on these families, researchers narrowed down from roughly 20,000 genes to just 350 candidates, then identified 12 rare protein-altering variants likely tied to longer, healthier lives. One stood out: the CGAS mutation found in two separate long-lived families in the study.
CGAS, or cyclic GMP-AMP synthase, is a protein that triggers inflammation when DNA appears where it shouldn't be inside cells. This normally happens during viral infections or when cells suffer damage. The variant appears to reduce the inflammatory response while maintaining sufficient immune function to fight infections and repair cellular damage.
Pasquale Putter, the PhD student leading the research team, explained the logic. "It is likely that members of these families had only one active copy of the CGAS gene, rather than two, and that this will have reduced the inflammatory response in their bodies, while still being sufficient to clear infections and repair damage, thereby contributing to the protective mechanisms that enable extended healthspan and survival."
The theory makes biological sense. Chronic inflammation is one of the hallmarks of aging, linked to heart disease, cancer, and cognitive decline. A mutation that dials down this constant inflammatory burn while preserving immune defenses could plausibly extend the years people spend free from major disease.
But researchers are proceeding with caution. The CGAS pathway is delicate. Completely shutting it down could leave people defenseless against infections and tumors. Excessive activation triggers the opposite problem: chronic inflammation and tissue damage. Context matters enormously.
To understand how the mutation actually functions in living organisms, the team is moving beyond laboratory experiments. They plan to introduce the CGAS variant into killifish, the shortest-lived vertebrates on Earth with lifespans of three to nine months. The model will show whether the mutation genuinely extends lifespan and what health effects emerge in different tissues.
The family-based approach offers another advantage over studying isolated long-lived individuals. It allows researchers to separate genetic factors from socioeconomic status, lifestyle choices, and environmental influences, all of which heavily influence how long people live and how healthy they remain.
Conference chair Alexandre Reymond noted the broader significance. The findings help scientists "zoom in on factors tied to longevity and, more importantly, they point to what maybe are key elements to extend the healthspan of all."
Author Jessica Williams: "This is a crucial distinction between just living longer and actually staying healthy while you do it, and the CGAS finding suggests we might be able to replicate some of these protective mechanisms."
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