Alzheimer’s disease, the most prevalent form of dementia, typically occurs after the age of 65. A significant genetic factor associated with this type of Alzheimer’s at a younger age is a gene called apolipoprotein E (APOE), which comes in three common variations:

APOE e2: This form is the least common and is associated with a reduced risk of Alzheimer’s disease.

APOE e4: More prevalent than e2, this gene variant increases the risk of Alzheimer’s and is linked to a more severe form of the disease.

APOE e3: The most common variant, it does not seem to significantly affect the risk of developing Alzheimer’s.

It’s important to note that genes are not the sole determining factor in Alzheimer’s disease risk.

Each individual inherits one copy of the APOE gene from each parent. Having at least one APOE e4 gene doubles or triples the risk of developing Alzheimer’s disease. Some individuals inherit two APOE e4 genes, one from each parent, which substantially increases the risk, by about eight- to twelvefold.