Progeria is caused by mutations that weaken the structure of the cell nucleus, making normal cell division difficult. The histone mark H4K20me3 is involved in Hutchinson-Gilford Progeria syndrome caused by de novo mutations that occurs in a gene that encodes lamin A. Lamin A is made but isn't processed properly. This poor processing creates a really abnormal nuclear morphology and disorganized heterochromatin. Patients also don't have appropriate DNA repair, and they also have increased genomic instability.