An overlap between DCM and long-QT3 resulting from abnormalities of the sodium channel gene SCN5A have been described in multiple reports (Kwon et al., 2012; Shi et al., 2008), but there is also evidence for an association between long-QT1 and idiopathic DCM (Allen et al., 2016). Here, SCN5A is linked to familial dilated cardiomyopathy.