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Brugada syndrome (BrS) is a genetic disease that is characterised by abnormal electrocardiogram (ECG) findings and an increased risk of sudden cardiac death. It is named by the Spanish cardiologists Pedro Brugada and Josep Brugada. It is the major cause of sudden unexplained death syndrome (SUDS), also known as sudden adult death syndrome (SADS), and is the most common cause of sudden death in young men without known underlying cardiac disease in Thailand and Laos. Although the ECG findings of Brugada syndrome were first reported among survivors of cardiac arrest in 1989, it was only in 1992 that the Brugada brothers recognized it as a distinct clinical entity, causing sudden death by causing ventricular fibrillation (a lethal arrhythmia) in the heart. == Genetics == Approximately 20% of the cases of Brugada syndrome have been shown to be associated with mutations in a gene that encodes for a sodium ion channel in the cell membranes of the muscle cells of the heart (the myocytes); this is often referred to as a ''sodium channelopathy''. The majority of patients affected by Brugada syndrome are not found to have known genetic mutations to explain the disease, as of 2015.〔Genet Med. 2015 Apr 23. doi: 10.1038/gim.2015.35. Brugada syndrome: clinical and genetic findings. Sarquella-Brugada G1, Campuzano O2, Arbelo E3, Brugada J4, Brugada R5.〕 The gene, named SCN5A, is located on the short arm of the third chromosome (3p21). Loss-of-function mutations in this gene lead to a loss of the action potential dome of some epicardial areas of the right ventricle. This results in transmural and epicardial dispersion of repolarization. The transmural dispersion underlies ST-segment elevation and the development of a vulnerable window across the ventricular wall, whereas the epicardial dispersion of repolarization facilitates the development of phase 2 reentry, which generates a phase 2 reentrant extrasystole that captures the vulnerable window to precipitate ventricular tachycardia and/or ventricular fibrillation that often results in sudden cardiac death. At present time however, all the reported patients who died because of the disease and were submitted to detailed autopsy study have shown a structural right ventricular pathology underlying the syndrome. Over 160 mutations in the SCN5A gene have been discovered to date, each having varying mechanisms and effects on function, thereby explaining the varying degrees of likelihood of the genetic mutation leading to the disease ( that is to say, penetrance) and expression of this disorder. An example of one of the mechanisms in which a loss of function of the sodium channel occurs is a mutation in the gene that disrupts the sodium channel's ability to bind properly to ankyrin-G, an important protein mediating interaction between ion channels and cytoskeletal elements. Very recently a mutation in a second gene, Glycerol-3-phosphate dehydrogenase 1-like gene () has been shown to result in Brugada syndrome in a large multigenerational family (London, 2006). This gene acts as an ion channel modulator in the heart, although the exact mechanism is not yet understood. Recently Antzelevitch has identified mutations in the L-type calcium channel subunits ( (A39V and G490R) and (S481L)) leading to ST elevation and a relatively short QT interval (below 360 ms). For a comprehensive list of all mutations see 〔 In 2013, Bezzina et al. showed that common variants at SCN5A-SCN10A and HEY2 are associated with Brugada syndrome.〔 This condition is inherited in an autosomal dominant pattern and manifests itself more commonly in males, due to a higher penetrance. In addition it has a higher prevalence in most Asian populations. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Brugada syndrome」の詳細全文を読む スポンサード リンク
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