The risk factor for Alzheimer’s APOE4 may be a separate form of the disease

FFor more than three decades, Alzheimer’s researchers have considered APOE4 a major genetic risk factor for most cases of the devastating neurological disease. But a new study published Monday claims this gene variant plays an even more important role than scientists realized, causing a distinct form of Alzheimer’s disease.

Researchers analyzed data from more than 13,000 people, including nearly 800 APOE4 homozygotes, people who carry two copies of the gene variant. They found that almost all homozygotes showed biological signs of Alzheimer’s disease in the brain, and that they typically developed dementia and other symptoms, and died earlier than people with Alzheimer’s disease who do not have APOE4.

The research team also found that APOE4 homozygotes showed a predictable pattern of biomarker changes associated with Alzheimer’s disease, including a buildup of beta-amyloid and tau, a protein linked to neuron damage and death.