Given that HAP40 binds full-length HTT (fl-HTT), but not its N-terminal region alone [35,36], we next tested another well-characterized fly HD model, which expresses mutant human fl-HTT with 128Q (fl-HTT-128Q) or wildtype control of fl-HTT with 16Q (fl-HTT-16Q) [52]. The gene discussed is HTT; the disease is Huntington disease.