Moreover, the Lrp6-CKO mice between 6 and 8 weeks after tamoxifen administration were highly susceptible to ventricular tachycardia or fibrillation (75%) and sudden cardiac death (50%) when they were subjected to a stress-inducing protocol; conversely, no severe arrhythmia events were observed as mentioned above in Cre transgene control mice (Fig. 6g,h). The gene discussed is LRP6; the disease is ventricular tachycardia.