We found that manifest HD (but not pre-manifest HD) had significantly higher epigenetic AgeAccel than controls (0.098 ≤ p ≤ 2.0 × 10−4, Fig. 3), led by the pan-tissue clock (AgeAccel, p = 2.0 × 10−4, Fig. 3a) and AgeAccelGrim (p = 2.4 × 10−4; Fig. 3f). Here, CLOCK is linked to Huntington disease.