APOE4, a form of the apolipoprotein E gene, is a genetic risk factor for developing dementia, including Alzheimer’s disease. According to the National Institute of Aging (NIA), roughly 25% of the human population carries one copy of APOE4. And ~2-3% of people carry two copies of the APOE4 gene.
While there is a strong association between APOE4 carriers and those who develop dementia (APOE4 is carried by almost half of all Alzheimer’s patients), inheriting the APOE4 gene doesn’t ensure one will certainly develop the disease. However, those with two copies of the APOE4 gene reportedly have an 8-12 times greater chance of developing the disease.