This notion is accompanied by reduced myelin- and oligodendrocyte-related protein levels in the AD and SZ brains, such as myelin basic protein (MBP), myelin proteolipid protein (PLP), cyclic nucleotide phosphohydrolase (CNP), myelin-associated glycoprotein (MAG), and myelin oligodendrocyte glycoprotein (MOG), indicating a loss of myelin. This evidence concerns the gene PLP1 and Alzheimer disease.