HTT and Huntington disease: However, researchers recently did not only generate HD pig model (Yan et al. 2018a), but also eliminated mutant HTT protein and relieved neuropathology by CRISPR/Cas-mediated inactivation of mutant HTT gene in vitro model (Shin et al. 2016; Kolli et al. 2017) and in mice model (Monteys et al. 2017; Yang et al. 2017), which provides promise for its cure.