Reduced numbers of Olig2-positive cells in the postmortem human AD cortex have been reported (Behrendt et al., 2013), and myelin loss with reduced amounts of myelin basic protein (MBP), myelin proteolipid protein, cyclic nucleotide phosphohydrolase and cholesterol have been identified in postmortem AD brains (Roher et al., 2002; Benitez et al., 2014). The gene discussed is PLP1; the disease is Alzheimer disease.