Christopher Newton-Cheh and colleagues report genome-wide association analyses for QT interval, an electrocardiographic measure reflecting myocardial repolarization, in 100,000 individuals. They identify 35 loci associated with QT interval and highlight a role for calcium regulation in myocardial repolarization. The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8–10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval–associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD.

Background: Pulmonary arterial hypertension consists in an increase of mean pulmonary arterial pressure (PAPm ≥ 25 mmHg), and may lead to right ventricular failure. Pulmonary arterial hypertension can arise in several disorders, encompassing inflammatory conditions and connective tissue diseases. The occurrence of pulmonary arterial hypertension has recently been reported in monogenic interferonopathies and in systemic lupus erythematosus, highlighting the pathogenic role of type I interferons and paving the way to therapies aimed at inhibiting interferon signaling.Case: We describe a 17‐year‐old boy with DNase II deficiency, presenting a clinical picture with significant overlap with systemic lupus erythematosus. During treatment with the Janus kinase inhibitor ruxolitinib, he developed pulmonary arterial hypertension, raising the question whether it could represent a sign of insufficient disease control or a drug‐related adverse event. The disease even worsened after drug withdrawal, but rapidly improved after starting the drug again at higher dosage.Summary and conclusion: Pulmonary arterial hypertension can complicate type I interferonopathies. We propose that ruxolitinib was beneficial in this case, but the wider role of Janus kinase inhibitors for the treatment of pulmonary arterial hypertension is not clear. For this reason, a strict cardiologic evaluation must be part of the standard care of subjects with interferonopathies, especially when Janus kinase inhibitors are prescribed.

Congenital long QT syndrome (LQTS) represents a disorder of myocardial repolarization characterized by a prolongation of QTc interval on ECG, which can degenerate into fast polymorphic ventricular arrhythmias. The typical symptoms of LQTS are syncope and palpitations, mainly triggered by adrenergic stimuli, but it can also manifest with cardiac arrest. At least 17 genotypes have been associated with LQTS, with a specific genotype–phenotype relationship described for the three most common subtypes (LQTS1, -2, and -3). β-Blockers are the first-line therapy for LQTS, even if the choice of the appropriate patients needing to be treated may be challenging. In specific cases, interventional measures, such as an implantable cardioverter-defibrillator (ICD) or left cardiac sympathetic denervation (LCSD), are useful. The aim of this review is to highlight the current state-of-the-art knowledge on LQTS, providing an updated picture of possible diagnostic algorithms and therapeutic management.