Male, born 1948, 2 healthy brothers, similar ages. Father: Alzheimer's diagnosed at age 70. Amyloid plaques confirmed by autopsy for a research study. Mother: Alzheimer's diagnosed at age 82. Maternal grandfather, probable Alzheimer's, ca age 80. Both parents otherwise healthy, normal weight. Although I am heterozygote ApoE4/ApoE3, and so, as male, with little additional risk, I am curious if any other of my genotypes are informative about risk for Alzheimer's. I am also curious if there is documented elevated risk when both parents have sporadic Alzheimer's. I recall a publication many years ago on this, but it may have been flawed due to recruitment bias. I have a PhD in biochem, and have worked in labs hunting for complex disease genes.