Indeed, inhibition of the BMI1 gene(component of the Polycomb repressive complex 1, whichpromotes chromatin compaction and gene silencing throughE3-mono-ubiquitin ligation activity mediated by Ring1a/b onhistone H2A at lysine 19 (H2Aub)) expression was found in the brain of AD patients. This evidence concerns the gene BMI1 and Alzheimer disease.