Involvement of the cardiac sodium channel in DM might also highlight the importance of considering polymorphism in the SCN5A gene, as well as in other genes such as SCN10A, as a possible cause of the clustering of cardiac alterations in some families of DM64, an hypothesis supported by the recent report that DM exacerbates Brugada syndrome caused by a mutation in SCN5A (ref. 65). Here, SCN10A is linked to Brugada syndrome.