The CETP gene variant makes cholesterol particles in the blood larger than normal. The researchers suggest smaller particles can more readily lodge in the lining of blood vessels, leading to fatty buildups, which are a risk factor for heart attacks and strokes.

Whether or not this gene variant protects the brain by preventing this buildup, or through some other mechanism, remains uncertain, says Barzilai. Future research should also investigate whether this gene has an effect on dementia associated with Alzheimer’s disease, says pathologist and human geneticist George Martin at the University of Washington.

Pharmaceutical companies are currently developing drugs that mimic the effect of this gene variant, says Barzilai. Unfortunately, one known as torcetrapib, manufactured by Pfizer, was pulled in December due to increased death and heart problems among study subjects, “but others in development aren’t seeing that, so it might just have been a problem with that drug,”