Importantly, patients who develop PH with atrial fibrillation have a higher mortality than PH patients without atrial fibrillation [49], suggesting that KCNK3-LOF mutations or KCNK3-dyfunction could also contribute to the clinical deterioration of PH favoring the occurrence of atrial fibrillation. The gene discussed is KCNK3; the disease is atrial fibrillation.