Brugada syndrome

Abstract

The Brugada syndrome is an autosomal dominant disease with incomplete penetrance that may cause syncope and sudden cardiac death in young individuals with a normal heart. It is characterized by an electrocardiographic pattern of complete or incomplete right bundle branch block and ST segment elevation in leads V1-V3. One of the genes linked to this syndrome is SCN5A, the gene encoding for the cardiac sodium channel. Mutations in SCN5A cause a functional reduction in the availability of cardiac sodium current in Brugada syndrome. However, only 20-25% of patients affected by this syndrome have mutations on this gene. A novel gene locus on chromosome 3, distinct from SCN5A, has been identified recently. The relative male preponderance of the phenotype, despite equal inheritance of the gene in males and females, has led to the speculation of a role for testosterone in the phenotype. The disease could manifest at first time as cardiac arrest without any previous symptom, and the electrocardiographic pattern could be intermittent, requiring a pharmacological challenge with Class I antiarrhythmic drugs to unmask ST elevation. Several conditions producing Brugada-like electrocardiographic patterns should be borne in mind and excluded while making a diagnosis of the Brugada syndrome. The management is difficult as pharmacological agents are not universally effective. The mode of treatment recommended by the majority of cardiac electrophysiologists is the implantation of a cardioverter defibrillator. Symptomatic patients with inducible ventricular arrhythmias and a positive family history should be considered for prophylactic implantation of a cardioverter defibrillator.

A mutation screen in patients with Kabuki syndrome

“…One patient, K1771, who carried the maternally transmitted p.S543L missense variant, showed most but not all of the key features of KS, while his mother was phenotypically unremarkable. Although the causative nature of this mutation remains uncertain, it might point toward incomplete penetrance of dominantly inherited MLL2 mutations, a finding that has already been described in other autosomal dominant developmental syndromes (Dodé andHardelin 2010, Francis andAntzelevitch 2005).…”

Brugada Syndrome and Carbohydrate Metabolism

“…Brugada syndrome is an arrhythmogenic and autosomal dominant disease with incomplete penetrance that may cause syncope and sudden cardiac death (SCD) in young individuals with a normal heart [6]. In addition, it is the syndrome of right bundle branch block (RBBB) that characterized by ST-segment elevation in precordial ECG leads V 1 to V 3 [7].…”

Early repolarization syndrome: Is it always benign?

“…Mutations of the SCN5A gene encoding for the cardiac sodium channel have been detected in 20 -25% of patients affected by the Brugada syndrome. The ECG features of the syndrome could be intermittent, requiring a pharmacological challenge with Class I antiarrhythmic drugs to unmask ST-segment elevation [3].…”