Dhaka, Oct. 13 -- A common genetic variant strongly associated with Alzheimer's disease may raise the risk of dementia partly by triggering a scarring process in the brain's blood vessels, The Guardian reports, citing new research published in the journal Cell.

The variant, known as APOE4, is found in roughly six out of every 10 Alzheimer's patients.

Despite its strong link to the disease, many carriers never develop dementia, leaving scientists puzzled about its precise role.

The new study, led by neuroscientist Joel Blanchard of the Icahn School of Medicine at Mount Sinai in New York City, offers a possible explanation.

Using a gene expression atlas built from data covering 66,000 cells drawn from 220 people, the team found that APO...