In studies employing a number of HD i-neurons with a range of CAG repeat lengths of 66, 71, and 109, Morozko et al. (2021)79 reported that the SUMO E3 ligase PIAS1 is involved in DNA damage control and that its reduction in HD iPSC neurons normalized HD transcriptional dysregulation associated with DNA damage repair. The gene discussed is PIAS1; the disease is Huntington disease.