However, in children and adults with DS, marks of premature senescence or accelerated ageing were seen in primary cells from organ systems other than CNS: immune cells,66 gingival cells, fibroblasts and lymphocytes.15, 16, 17, 18, 19, 20, 21, 22 The CpG-methylation defined “epigenetic clock” showed increased epigenetic ageing in primary blood cells from children67 and adults23 with DS. This evidence concerns the gene CLOCK and Dravet syndrome.