Longitudinal, genome-scale analysis of DNA methylation in twins from birth to 18 months of age reveals rapid epigenetic change in early life and pair-specific effects of discordance

Table 1 Twin pair characteristics

Twin pair ID number	Zygosity^a	Chorionicity^b	Twin 1 sex	Twin 2 sex	Gestational age	Birth weight discordance (%)^c	Samples removed after QC^d
1016	MZ	DC	M	M	37	5.4	T2_18
1022	MZ	MC	M	M	38	12.4	T1_18, T2 _18
1024	MZ	DC	F	F	37	12.1	T2_B
1032	DZ	DC	F	F	37	43.3	T1_18
1035^e	MZ	MC	F	F	35	30.8
1042	DZ	DC	M	M	30	19.8
1046	MZ	DC	M	M	37	6.2
1057	DZ	DC	M	M	37	13.3
1058	MZ	DC	M	M	36	22.0
1072	DZ	DC	F	F	37	14.5
1107	MZ	MC	F	F	33	8.1	T1_18
1126	MZ	MC	F	F	32	27.3	T2_18
2034	MZ	DC	F	F	36	3.6
3006	DZ	DC	M	M	37	3.6
3014	MZ	MC	M	M	36	18.0

^aMZ, monozygotic; DZ, dizygotic. ^bMC, monochorionic; DC, dichorionic. ^c[(Weight of heaviest twin - Weight of lightest twin)/Weight of heaviest twin] × 100. ^dT1/T2, twin 1/2; B, birth sample; 18, 18 months sample. ^eTwin-to-twin transfusion syndrome.

ISSN: 1474-760X