Schematic diagram of the studied CpG sites in the <i>IGF2BP1</i> gene.

<p>Top: depiction of chromosome 17 with a red mark indicating the locus of <i>IGF2BP1</i> (chr17:47,074,774–47,133,012). Bottom: location of cg07075026 and cg20966754 CpG sites, represented over an intron in a transcript of <i>IGF2BP1</i> at chr17:47,074,774–47,133,507. Red vertical squares crossing the transcript cover exonic regions. Adapted from the UCSC Genome Browser (GRCh37/hg19; <a href="http://genome.ucsc.edu" target="_blank">http://genome.ucsc.edu</a>).</p

Demographic, clinical, neurocognitive, obstetric and cortical variables for concordant, discordant and healthy MZ twin pairs.

<p><i>Abbreviations</i>: m = males; f = females;</p><p>⁺ = lifetime diagnoses according to the Diagnostic and Statistical Manual of Mental Disorders; SD = standard deviation; IQ = intellectual quotient; BW = birth weight; ICV = total intracranial volume; SA = surface area</p><p>^<i>a</i> = X-square and <i>p</i>-value estimates for gender data were obtained using Monte Carlo tests with 10⁶ replicates</p><p>^<i>b</i> = Kruskal-Wallis X-square, as these variables were continuous</p><p>* = statistically significant <i>p</i>-value.</p><p>Demographic, clinical, neurocognitive, obstetric and cortical variables for concordant, discordant and healthy MZ twin pairs.</p

Nine anatomical ROIs for analysis of associations between SA and any of BW, IQ or depression/anxiety.

<p>Additional details on ROI selection and nomenclature can be found in <i>Methods</i>.</p

Representation of the association between working memory and DNA methylation level of cg07075026 and cg20966754.

<p>The black line (“Whole WM”) was obtained from the first regression test (i.e., using raw WM from each of the 34 individuals), whereas blue and red lines (“Familial WM” and “Unique environment WM”) represent outcomes from the model evaluating familial and unique environmental factors.</p

Results of the linear regression testing the association between <i>IGF2BP1</i> DNA methylation levels and both BW and WM.

<p>Mean methylation percentage of cg07075026 and cg20966754 was used as outcome. Analyses were adjusted for gender, age, weeks of gestation and IQ, and accounted for correlated responses from twin pairs using a mixed effects model. BW was introduced in kilograms and WM in standard units. SE: Standard error.</p><p>Results of the linear regression testing the association between <i>IGF2BP1</i> DNA methylation levels and both BW and WM.</p

Representation of the association between birth weight and DNA methylation level of cg07075026 and cg20966754.

<p>The black line (“Whole BW”) was obtained from the first regression test (i.e., using raw BW from each of the 34 individuals), whereas blue and red lines (“Familial BW” and “Unique environment BW”) represent outcomes from the model evaluating familial and unique environmental factors.</p

Results of the linear regression testing the association between <i>IGF2BP1</i> DNA methylation level and the familial and unique environmental factors of both BW and WM.

<p>Mean methylation percentage of cg07075026 and cg20966754 was used as outcome. Analyses were adjusted for gender, age, weeks of gestation and IQ, and accounted for correlated responses from twin pairs using a mixed effects model. BW was introduced in kilograms and WM in standard units. SE: Standard error.</p><p>Results of the linear regression testing the association between <i>IGF2BP1</i> DNA methylation level and the familial and unique environmental factors of both BW and WM.</p

Descriptive data for variables included in the analyses.

<p>MZ  =  monozygotic; SD  =  standard deviation; BW  =  birth weight; WM  =  working memory; IQ  =  intellectual quotient; *: average methylation fraction of cg07075026 and cg20966754 (<i>IGF2BP1</i>) (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103639#s2" target="_blank">Materials and methods</a>: b. CpG region selection).</p><p>Descriptive data for variables included in the analyses.</p

Significant AAL regions of the ROI analysis of Dataset1 (p<0.05, Bonferroni corrected).

<p>Significant AAL regions of the ROI analysis of Dataset1 (p<0.05, Bonferroni corrected).</p

Statistics of the significant ROIs (p<0.05, cFWE corrected) of the VBM analysis of Dataset1.

<p>Degrees of freedom: [1 785]. t-stat threshold: 3.1.</p