An intellectual advantage (Image: Joerg Sarbach/AP/PA)

A GENE variant that ups your risk of developing Alzheimer’s disease in old age may not be all bad. It seems that young people with the variant tend to be smarter, more educated and have better memories than their peers.

The discovery may improve the variant’s negative image (see “Yes or no”). It also suggests why the variant is common despite its debilitating effects in old age. Carriers of the variant may have an advantage earlier in life, allowing them to reproduce and pass on the variant before its negative effects kick in. …