The above-mentioned phenomenon could be caused by: (a) the variants SCN1B, SCN2B, SCN3B, SCN4B, SCN5A, and SCN10A of Na+ channel genes; (b) junctophilin mutation (E169K), which was found to enhance the RyR2 Ca2+ leak, leading to the juvenile onset of AF; (c) a single nucleotide polymorphism (SNP) in CASR, which encodes a Ca+2-sensing receptor that detects extracellular calcium ion levels and regulates calcium homeostasis [92]. Here, RYR2 is linked to atrial fibrillation.