HMGN1 and Alzheimer disease: The available information supporting the role of HMGN1 in DS-AD through the decrease in H3K27me3 and increase in H3K27ac is somewhat controversial since some studies of human postmortem AD brain tissue show different H3K27 modification and based on our knowledge, no genome-wide studies focused on H3K27 marks in DS-AD human brains were performed.