CASP6 and Huntington disease: Expression of the resulting mHtt-586 N-terminal fragment aggravates the phenotype of HD mice (Waldron-Roby et al., 2012), whereas a 586 cleavage-resistant mutant or caspase 6 knockout attenuates the phenotype (Gafni et al., 2012; Graham et al., 2006; Pouladi et al., 2009; Wong et al., 2015).