Casp2-/- mice are protected from locomotor symptoms of HD in the YAC128 mouse. At 7 months of age, YAC128 mice display decreased locomotor activity and increased anxiety, as measured by time spent in the center of the arena, during exploration of an open field as compared to WT mice. Casp2-/- and casp2-/-;YAC128 mice perform similarly to WT mice. Mean="+", horizontal bars = quartiles. N = 15 WT mice, 21 YAC128 mice, 17 casp2-/- mice and 15 Casp2-/-;YAC128 mice. Post-hoc Newman-Keuls genotype comparisons "*" indicates p < 0.05.