Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an autosomal 
dominant inherited disorder characterized by adrenergic induced polymorphic 
ventricular tachycardias and associated with sudden cardiac death. The human 
cardiac ryanodine receptor gene (RyR2) was linked to CPVT. A 20-year-old male 
was referred to our hospital because of recurrent syncope after physical and 
emotional stress. Routine cardiac examinations including catheterization 
revealed no structural abnormality. Exercise on treadmill induced premature 
ventricular contraction in bigeminy and bidirectional ventricular tachycardia 
was induced during isoproterenol infusion. Beta-blocking drug was effective in 
suppressing the arrhythmias. We performed genetic screening by PCR-SSCP method 
followed by DNA sequencing, and a novel missense mutation R2401H in RyR2 located 
in FKBP12.6 binding region was identified. This mutation was not detected in 190 
healthy controls. Since FKBP12.6 plays a critical role in Ca channel gating, the 
R2401H mutation can be expected to alter Ca-induced Ca release and E-C coupling 
resulting in CPVT. This is the first report of RyR2 mutation in CPVT patient 
from Asia including Japan.