MYBPC3 and cardiac hypertrophy: Expression of Nppa was higher in cMyBP-C−/− and cMyBP-C+/− vs. WT hearts at PND0, prior to the onset of gross cardiac hypertrophy in cMyBP-C−/− mice (see Figure 3, bottom), and was also higher at PND2 and PND9 in cMyBP-C−/− hearts (Figures 4A,C).