A study from Japan of 303 BrS, ARVC patients with no SCN5A variant suggested that two TCAP gene mutants c.145G > A: p.E49K (chr17: 37822003) and c.458G > A: p.R153H (chr17: 37822316) lead to structural changes in their transcription products telethonin structural alterations, which in turn lead to structural breakage of the z-disk between cardiomyocytes, ultimately causing loss of function of the cardiac Na channel (Nav1.5) [31]. The gene discussed is SCN5A; the disease is Arrhythmogenic right ventricular dysplasia.