Table 1.

DNA methylation and periconceptional exposure to famine

Gene locusa	Average methylation, % (SD)	Within-pair differenceb, Δ%	Effect sizec, SD units	P-valued	Bonferroni-corrected P-valuee
IL10	20.8 (6.5)	2.4	0.37	1.8 × 10−6	2.7 × 10−5
GNASAS	48.8 (4.7)	1.1	0.24	3.1 × 10−6	4.7 × 10−5
INSIGF	84.8 (2.6)	−1.6	−0.61	2.3 × 10−5	3.5 × 10−4
LEP	28.6 (4.9)	1.2	0.24	2.9 × 10−3	4.4 × 10−2
MEG3	54.0 (2.4)	0.5	0.21	8.0 × 10−3	0.12
ABCA1	19.9 (4.2)	0.7	0.17	0.017	0.26
ABCA1 methf	36.9 (8.2)	1.7	0.21	8.2 × 10−4	0.012
KCNQ1OT1	30.1 (1.5)	−0.2	−0.16	0.053	NS
GRB10	47.2 (4.6)	0.4	0.08	0.091	NS
GNASAB	40.3 (5.0)	0.6	0.11	0.092	NS
APOC1	16.7 (3.1)	−0.5	−0.17	0.13	NS
IGF2R	84.1 (6.9)	−0.7	−0.10	0.29	NS
FTO	97.3 (0.8)	−0.5	−0.61	0.28	NS
CRH	58.9 (6.0)	0.4	0.07	0.61	NS
TNF	9.6 (1.7)	0.1	0.06	0.63	NS
NR3C1	4.8 (1.1)	0.0	−0.01	0.79	NS

^aTable sorted on P-value.

^bAverage absolute difference in DNA methylation between exposed and unexposed siblings.

^cObserved within-pair difference divided by the standard deviation in the sibling controls.

^dTwo-sided P-value resulting from a linear mixed model accounting for family relations, bisulphite batch and age at blood draw.

^eThe Bonferroni-corrected P-values. Results that were already not significant before Bonferroni correction are shown as NS.

^fSeparate analysis of methylated CpGs in ABCA1. In contrast to the 3′ CpGs, 5′ CpG dinucleotides (n = 13) were methylated. The methylation of the methylated 5′ CpGs was highly correlated (r > 0.87) among themselves, but not with the methylation of the 3′ CpG dinucleotides, which had little to no methylation (<4.5%).