MMRN1 and progeroid syndrome: In the progeria cell line HGPS 3 that expresses low LAP2α and high progerin levels (Fig. 1; Supplemental Fig. S1), ECM mRNA levels were significantly reduced (Supplemental Fig. S5A), while, in cell line HGPS 1 that expresses low progerin and normal LAP2α levels (Supplemental Fig. S1), ECM expression was similar to that of wild-type cells.