In evaluating factors that associate with SORL1 expression, we arrived at a model that includes (i) AD-associated neuropathology, as reflected by Braak stage, (ii) neuronal gene expression, as reflected by synaptophysin expression, and (iii) a SORL1 intron 1 SNP, rs661057, that has been associated with AD in at least some series [8]. Here, SYP is linked to Alzheimer disease.