Our blood EWAS of HD progression in manifest HD cases found three genome-wide significant CpGs: cg26919387 (meta-analysis p = 9.3 × 10−9) in PEX14, cg12823408 near GRIK4 (meta-analysis p = 3.0 × 10−8), and cg21497164 in COX4I2 (meta-analysis p = 6.5 × 10−8; Fig. 1b, Supplementary Fig. 18, Supplementary Table 11, and Supplementary Data 3). Here, COX4I2 is linked to Huntington disease.