A study that compared HGPS patient cells with the skin cells from young and elderly normal human subjects found similar defects in the HGPS and elderly cells, including down-regulation of certain nuclear proteins, increased DNA damage, and demethylation of histone, leading to reduced heterochromatin.[51] Nematodes over their lifespan show progressive lamin changes comparable to HGPS in all cells but neurons and gametes.[52] These studies suggest that lamin A defects are associated with normal aging.