LMNA and Failure to thrive: Homozygous LmnaG609G/G609G mice express progerin, lamin C, and residual levels of lamin A and show many HGPS features, including failure to thrive, bone defects, loss of fat deposits, bradycardia, prolonged QRS waves (indicating altered heart ventricular depolarization), and premature death [45,49,52].