While the clinical overlap between cardiac arrhythmias and epilepsy has been well-established for LQT-associated channelopathies related to the SCN5A and KCNH2 genes (5, 7, 17), and epileptic seizures were found in 12% of patients with LQT syndrome associated with KCNQ1 mutations (4), little is known about the detailed mechanisms and additional genetic risk factors leading to coincidental affection of heart and brain. Here, SCN5A is linked to cardiac rhythm disease.