BACE1 and Alzheimer disease: Finally, we identify a SNP approximately 15kb upstream of the MIR20B gene that is associated with AD-related cerebrospinal fluid (CSF) biomarker levels, specifically the 42 amino acid Aβ peptide (Aβ1-42) and with AD-associated neuroanatomical variation. These data take their place alongside our studies of miRNA regulation of BACE1, membrane metallo-endopeptidases (MME), and RE1 silencing transcription factor (REST) in PHB cultures and donated tissue from subjects who died with mild cognitive impairment (MCI) as well as AD and NCI subjects [48–53].