Supporting information

Supporting Information Additional supporting information can be found online in the Supporting Information section. File S1: Full description of patient recruitment, sample collection, sequencing, variant prioritisation, polygenic risk score analysis, RNA sequencing, mono‐allelic expression analysis, DNA methylation analysis, cross‐cohort differential methylation analysis and methylation pathway analysis. Figure S1: Assessment of batch correction for cross‐cohort DNA methylation data using principal component analysis (PCA). Figure S2: Polygenic risk scores for common neurodevelopmental and psychiatric phenotypes in patients with NDD and/or CHD compared with healthy control subjects. Figure S3: RNA sequencing validation of splice‐site variants. Figure S4: Epigenetic age estimates by disease group using EN and Levine clocks. Table S1: Data types available for each study participant. Table S2: Neurodevelopmental disorder (NDD) and congenital heart disease (CHD) genes used for variant curation. Table S3: Genes with aberrant expression identified by RNA sequencing. Table S4: Pathway enrichment analysis of differentially methylated regions.