Out of the nine genes with differential DNA methylation between peripheral blood leukocytes (PBLs) from DS adults and karyotypically normal controls reported by Kerkel et al.[27], three genes (TCF7, FAM62C, and CPT1B) were also similarly differentially methylated in the placenta villi in this study (p<1.8×10−9, see methods). This evidence concerns the gene TCF7 and Dravet syndrome.