For example, HGPS is caused by germline mutations in the LMNA gene, leading to the expression of progerin, a truncated mutant form of lamin A. Cultured cells from HGPS patients show abnormal nuclear morphology, including enlarged nuclei and heterochromatin loss with decreased H3K9me3 and reduced HP1 expression [62,65,66]. Here, LMNA is linked to Hutchinson-Gilford progeria syndrome.