PSEN2 and early-onset autosomal dominant Alzheimer disease: Genes that have been previously associated with Alzheimer’s disease include B-amyloid precursor protein, presenilin, presenilin 2, as well as apolipoprotein E. A database of genetic associations for Alzheimer’s disease exists [3] along with a resource provided by the National Institutes of Health for replicated genetic associations from genome-wide association studies of a variety of diseases including LOAD [4].