HDAC6 and Down syndrome: In addition, PACS1 syndrome patient cells contain PACS1(PACS1R203W)+/HDAC6+ p62 bodies (Fig. 2d), and dendrites from PACS1R203W neurons contain numerous varicosities, suggesting PACS1 syndrome may involve a possible degenerative process frequently described in epilepsy, infantile neurobehavioral failure, and neurodegenerative disorders (Fig. 5a)57.