Since HDACs are involved in neurogenesis, brain function, and neurodegenerative diseases, they have become potential therapeutic targets for treating neurodegenerative diseases such as AD and PD.175,176 HDAC2, neither HDAC1 nor HDAC3, is increased by AD-related neurotoxic stimuli in vitro, in two models of neurodegeneration in mice and in patients with AD. The gene discussed is HDAC2; the disease is Parkinson disease.