In 2019, scientists identified a Colombian woman who, as a result of her genes, should have experienced symptoms of Alzheimer’s disease starting in her 40s. However, for 30 years, she showed no symptoms.
Scientists looked at her DNA and checked her brain closely. They discovered she actually had a special type of the APOE gene, known as the Christchurch variant. She had two of these rare variants, in fact.
The woman, Aliria Rosa Piedrahita de Villegas, eventually did get dementia in her 70s. She passed away at 77 from cancer, according to The Washington Post.
However, she was just one such person. This raised a question, nonetheless. Could her circumstances be the answer to preventing Alzheimer’s in others, too?
On Wednesday, researchers published a study in The New England Journal of Medicine. They found 27 members of an extended Colombian family with a genetic risk for Alzheimer’s, along with one copy of the Christchurch gene.
These individuals experienced a delay in cognitive decline by about five years. This suggests a drug mimicking this gene could have similar benefits.
Christchurch variant of APOE gene delayed onset of Alzheimer’s by 5 years in 27 patient study. Only one copy is required, thus making it far easier to develop drugs that emulate the effect
An antibody drug that imitates Christchurch showed reduced buildup of tau tangles in mice pic.twitter.com/26EazWo63M
— Mackenzie Morehead (@mackenziejem) June 21, 2024
Joseph F. Arboleda-Velasquez, an associate scientist at Mass Eye and Ear in Boston and co-author of the study, emphasized caution. “We are taught in medicine to be wary of not drawing too many conclusions” from a single patient.
“Maybe it was related to something she ate or didn’t eat. Maybe it’s something related to the water in the house. The idea of finding 27 people—some lived in the city, some lived in rural areas—increases our confidence in the discovery—and shows the results are reproducible,” he further explained.
Severe Alzheimer’s disease linked to mutation in Presenilin 1 gene
Forty years ago, Francisco Lopera, a neurologist at the University of Antioquia in Medellín, Colombia, began treating patients with a severe type of Alzheimer’s disease passed down through families.
Symptoms of memory loss began around age 45, with full dementia setting in before 50. However, patients typically passed away in their 60s. Scientists linked this disease to a mutation in the gene Presenilin 1, affecting approximately 1,200 individuals across an extended family lineage.
Piedrahita de Villegas showed scientists it was possible to overcome this severe genetic fate. To turn her unique case into broader medical knowledge, scientists need to confirm the gene is responsible for the beneficial effect and can work similarly in others, as reported by The Washington Post.
Everyone has two copies of the APOE gene, one from each parent. Having two copies of the Christchurch variant like Piedrahita de Villegas is “rare, extremely rare,” said Yakeel T. Quiroz, a clinical neuropsychologist at Massachusetts General Hospital. Hence, researchers began searching for people with only a single copy.