Reacción a "Reactions: Spanish researchers propose new genetic form of Alzheimer's disease"

I do not see anything in this paper to justify the claim that carrying two copies of APOE4 represents some "distinct genetic form" of Alzheimer's disease. It has been known for decades that APOE4 is a strong risk factor for Alzheimer's disease, that people carrying two copies are at high risk and that people carrying two copies are at substantially higher risk than those carrying one. No matter how many alleles of APOE4 one carries the underlying disease processes seem similar across cases of Alzheimer's disease, suggesting that any effective treatment and prevention strategies, which have yet to be developed, would have broad applicability.