The TGF-beta isoform upregulated in both mouse and human HCM, as well as ET1-treated cardiac myocytes, was TGFB2. Differential expression of TGFB isoforms has also been reported in DCM mice (45), but the mechanisms underlying differential regulation of TGFB1 and TGFB2 genes, and the implications of these differences on HCM pathophysiology is unknown. The gene discussed is TGFB1; the disease is familial dilated cardiomyopathy.