Sudden cardiac death is defined as an unpredictable death within 24 hours. It is 
estimated to occur with a frequency of more than 50,000 per year in Japan. The 
inherited arrhythmogenic diseases associated with the transmembranous ionic 
channels, anchoring proteins or intracellular calcium regulating proteins are 
thought to be responsible for sudden cardiac death in infants, children, and 
young adults who have structurally normal hearts. Recent genetic analyses have 
identified congenital diseases such as the long-QT syndrome (LQTS), the Jervell 
and Lange-Nielsen syndrome (JLNS), the Brugada syndrome (BrS), the short-QT 
syndrome (SQTS), the arrhythmogenic right ventricular cardiomyopathy type 2 
(ARVC2), and the catecholamine-induced polymorphic ventricular tachycardia 
(CPVT) /familial polymorphic ventricular tachycardia (FPVT). Loss of function in 
the slow component of the delayed rectifier potassium current (I(Ks)) channels 
(KCNQ1, KCNE1), the rapid component of the potassium current (I(Kr)) channels 
(KCNH2, KCNE2) and the inward rectifier potassium current (I(Kl), Kir2.1) 
channel (KCNJ2) is linked to the LQTSs (type 1, 2, 5, 6, and 7 (Andersen 
syndrome)) and the JLNSs (type 1 and 2). Changes of function in the 
alpha-subunit of cardiac sodium channels (SCN5A) is also linked to the LQTS type 
3 and the BrS. A mutation in the ankyrin-B, anchoring proteins, has been 
identified as cause of the LQTS type 4. The SQTS is caused by gain of function 
in the KCNH2. Further, the missense mutations in the gene encoding ryanodine 
receptor 2 (RyR2) or calsequestrin 2 (CASQ2) that regulate intra-cardiac calcium 
handling is possibly implicated in the ARVC2 and the CPVT/FPVT. Herein, we 
present a review of the literature regarding the genetic mechanisms of the 
inherited arrhythmogenic diseases.