HDAC9 and Alzheimer disease: Fischer et al tested the effects of the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) and showed it could reinstate physiological exon usage associated with H4K12 acetylation and plasticity gene expression in aged neurons, but this was not found in AD neurons, where the beneficial effect of SAHA was only partial (Benito et al, 2015).