SYT1 and persistent truncus arteriosus: Representative gross images of hearts taken from Syt1+/− and WT mice 8 weeks after TAC or sham surgeries were shown in Fig. 3G. The body weights of mice did not show significant differences among groups (Fig. 3H), while the heart weight to body weight ratio (HW/BW) were higher in Syt1+/− mice than in WT mice 8 weeks after TAC (Fig. 3I), indicating that SYT1 deficiency aggravates TAC-induced cardiac hypertrophy.