HOPX and cardiac hypertrophy: For example, the expression of natriuretic peptide A (Nppa), natriuretic peptide B (Nppb), myosin heavy chain 7 (Myh7), myosin light chain 4 (Myl4), myosin binding protein H-like (Mybphl), canopy FGF signaling regulator 2 (Cnpy2), cysteine and glycine-rich protein 3 (Csrp3), homeodomain-only protein X (Hopx), and peroxiredoxin 2 (Prdx2) was increased in Prdm16CKO compared with control, suggesting that cardiac hypertrophy occurs in Prdm16CKO (S3 Fig in S1 File).