A unique methylation pattern co-segregates with neural tube defect statuses in Han Chinese pedigrees

Neural tube defects (NTDs) are a complex trait associated with gene-environment interactions. Folic acid deficiency and planar cell polarity gene mutations account for some NTD cases; however, the etiology of NTDs is still little understood. In this study, in three Han Chinese NTD pedigrees (two with multiple affected children), with no information on folic acid deficiency or supplement, we examined genome-wide methylation profiles of each individual in these families. We further compared methylation status among cases and normal individuals within the pedigrees. A unique methylation pattern co-segregated with affected status: NTD cases had more hypermethylated than hypomethylated CpG islands; genes with different methylations clustered in pathways associated with epithelial-to-mesenchymal transition (ZEB2, SMAD6, and CDH23), folic acid/homocysteine metabolism (MTHFD1L), transcription/nuclear factors (HDAC4, HOXB7, SOX18), cell migration/motility/adhesion, insulin and cell growth, and neuron/axon development. Although the genetics of NTD are likely complex, epigenetic changes may concentrate in certain key pathways.