Table 1.

A total of 2164 methylation samples across blood, lymphoblastoid, and fibroblast tissues were used for human cross-sectional studies.

	Parameter
	Enroll-HD data 1 (N = 910)	Enroll-HD data 2a (N = 357 × 2)	Registry-HD (N = 376)	Registry-HD (N = 100)	CHDI (N = 64)
	DNA source
	Buffy coat	Buffy coat	Whole blood	Lymphoblastoid	Fibroblast
No. of individuals
Manifest HD	393	204	298	79	37
Pre-manifest	223	153	0	0	0
Control	294	0	78	21	27
Age
HDGEC	49 [18, 76]	45 [18, 76]	53 [19, 84]	52 [19, 82]	43 [31, 58]
Control	51 [18, 76]	–	49 [20, 84]	52 [20, 82]	41 [31, 55]
CAG length
HDGEC	43 [36, 51]	44 [37, 59]	45 [39, 67]	45 [39, 66]	44 [41, 50]
Controls	20 [16, 35]	–	21 [14, 33]	21 [17, 31]	–
Age of motor onset
HDGEC	46 [16, 73]	44 [17, 75]	44 [8, 75]	43 [8, 73]	–
DNA methylation
Array type	Illumina 450k	Illumina EPIC	Illumina 450k	Illumina 450k	Illumina 450k
Normalization method	Noob57	Noob57	Noob57	Noob57	Noob57
Data analysis	Clock, EWAS, regression	Clock, EWAS, regression	Clock, EWAS, regression	Clock, regression	Clock, regression

Columns 1–5 correspond to blood methylation data from Enroll-HD data 1, Enroll-HD data 2, and the Registry-HD, respectively. For each individual in the Enroll-HD data 2, two blood samples were collected (separated by roughly 7.9 years). Only the first sample is described in the table. The last row specifies the use of these data: epigenetic clock analysis, epigenome-wide association study (EWAS), and multivariate regression analysis. Both Enroll-HD¹⁰ and Registry-HD¹¹ are large-scale longitudinal observational cohorts for studying the onset and progression of Huntington’s disease. The last two columns correspond to non-blood methylation data from Registry-HD and CHDI, respectively. The CHDI Foundation is a privately funded, not-for-profit biomedical research organization devoted to a single disease—Huntington’s disease.

Continuous parameters are presented in the format of mean [min, max].

HDGEC refers to HD gene-expansion carriers (combining pre-manifest and manifest individuals).

^aHD status and age estimates reported for the first blood draw for the DNA methylation study. The dataset involves 714 methylation samples from two longitudinal measures across 357 individuals.