KAT5 and amyotrophic lateral sclerosis: To test whether disruption of Tip60 HAT/HDAC2 balance is a common early stage feature in additional NDs, we assessed expression levels of Tip60, and Drosophila HDAC1/2 ortholog, Rpd3, using RNA isolated from larval brains that model early neurodegenerative progression in each of the PD, HD and ALS conditions.