Rare gene mutation helps people resist Alzheimer’s disease

In 2019, researchers announced the discovery of an unusually resilient person — a Colombian woman who carried a ticking time bomb in her genes that should have triggered an aggressive, early form of Alzheimer’s disease, starting in her 40s. But for three decades, the bomb didn’t explode. Scientists studied her DNA and scanned her remarkable brain, ultimately tracing her protection to a rare version of the APOE gene, called the Christchurch variant. She had two copies. The extraordinary story of Aliria Rosa Piedrahita de Villegas, who did eventually develop dementia...