COL1A2 and familial dilated cardiomyopathy: The level of cardiac fibrosis and heart failure in DCM was significantly increased (logFC > 1 and p < 0.05, Figure 1B), which were indicated by collagen type I alpha 1 chain (COL1A1), collagen type I alpha 2 chain (COL1A2), collagen type III alpha 1 chain (COL3A1), natriuretic peptide A (NPPA), and natriuretic peptide B (NPPB).