HDAC9 and Werner syndrome: Several proteins important for DNA repair e.g., Ku70, flap structure-specific endonuclease 1 (FEN1), Werner syndrome (WRN), ataxia teleangiectasia mutated protein (ATM), mediator of DNA damage checkpoint 1 (MDC1) and DNA-dependent protein kinases (DNA PK) are regulated by acetylation which may be increased by HDAC inhibitors [136].