miR-133 is highly expressed in myocardium and skeletal muscle, and is involved in the development, differentiation, survival and electrical conduction of cardiomyocytes [100]; it is also implicated in cardiac hypertrophy, cardiac fibrosis, cardiac hypertrophy and heart arrhythmia, and it has been reported that miR-133 targets genes involved in cardiac hypertrophy, such as RhoA, Cdc42, Nelf-A/WHSC2, MAPK, TGFβ/Smad and PI3K/Akt [101]. The gene discussed is CDC42; the disease is cardiac hypertrophy.