There’s something special about the APOE2 variant of the APOE (apolipoprotein E) gene: People who carry it tend to live longer, and they have a lower risk of developing Alzheimer’s disease.

Scientists are still trying to figure out why, and now, they have a new lead.

A team led by researchers at the Buck Institute for Research on Aging in the US set out to answer that question using human stem cell-derived neurons and mouse studies.