Final answer:
The ApoE E4 allele is linked to a higher risk of developing Alzheimer's disease, due to its role in the genetic predisposition to this form of dementia.
Step-by-step explanation:
The presence of the ApoE E4 allele is associated with an increased risk of Alzheimer's disease. Apolipoprotein E (APOE) has several variants, with the E4 variant notably increasing a carrier's likelihood of developing Alzheimer's. Alzheimer's disease has both a rare early-onset form, caused by mutations in specific genes, and a more prevalent late-onset form, which has a genetic component linked to the APOE E4 allele. While different forms of Alzheimer's can share protein abnormalities with other neurodegenerative diseases, it is the association with the APOE E4 allele that is specifically relevant to an increased risk of Alzheimer's.