RT-PCR analysis showed that the increases in mRNA levels for Nppa (atrial natriuretic peptide), Myh7 (β-myosin heavy chain), and Acta1 (skeletal α-actin), as markers of pathological hypertrophy, were not significantly different between DCM and DCM/HET hearts (Figure 4(c)). Atp2a2 mRNA levels, which were reduced to 69 ± 4% of WT levels in DCM hearts, were lower in DCM/HET hearts (42 ± 4% of WT levels; Figure 4(d)). This evidence concerns the gene ACTA1 and familial dilated cardiomyopathy.