Besides anti-Ro/SSA, some lines of evidence suggest that other autoantibodies, i.e., anti-beta1-adrenergic receptor antibodies (anti-β1) and anti-voltage-gated potassium channel Kv1.4 antibodies (anti-Kv1.4), may be responsible of immuno-mediated forms of acquired LQTS. Here, KCNA4 is linked to familial long QT syndrome.