Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) exhibit accelerated aging phenotypes, which are caused by mutations in the LMNA or WRN genes, respectively. Accumulating evidence suggested that the mutations commonly caused senes- cent phenotypes such as DNA damage, cell cycle arrest, nuclear enlargement and nuclear shape abnormality. Furthermore, both mutations showed significant loss of nuclear lamina -binding proteins, a heterochromatin protein, and an epigenetic H3K9me3 mark in hetero- chromatin loci. These biochemical deficits might explain common molecular mechanism underlying the pathogenesis of the progeria.