Long Qt Syndrome 10, also known as atrial fibrillation, familial, 17, is related to second-degree atrioventricular block and diamond-blackfan anemia 3. An important gene associated with Long Qt Syndrome 10 is SCN4B (Sodium Voltage-Gated Channel Beta Subunit 4), and among its related pathways/superpathways are Transmission across Chemical Synapses and Cardiac conduction. Affiliated tissues include heart and atrioventricular node, and related phenotypes are atrial fibrillation and sudden cardiac death