NPPA and cardiac hypertrophy: In transgenic mouse hearts, the expression of these three variants resulted in cardiac hypertrophy, increased mTOR (mammalian target of rapamycin)/S6K1 (Ribosomal protein S6 kinase 1) and calcineurin-RCAN1.4 (regulator of calcineurin 1 isoform 4) signalling, and activated mRNA levels of hypertrophic markers, including ANP (atrial natriuretic peptide), BNP (B-type natriuretic peptide), and β-myosin heavy chain [19].