Update on Genetic Basis of Brugada Syndrome: Monogenic, Polygenic or Oligogenic?

Abstract

Brugada syndrome is a rare inherited arrhythmogenic disease leading to ventricular fibrillation and high risk of sudden death. In 1998, this syndrome was linked with a genetic variant with an autosomal dominant pattern of inheritance. To date, rare variants identified in more than 40 genes have been potentially associated with this disease. Variants in regulatory regions, combinations of common variants and other genetic alterations are also proposed as potential origins of Brugada syndrome, suggesting a polygenic or oligogenic inheritance pattern. However, most of these genetic alterations remain of questionable causality; indeed, rare pathogenic variants in the SCN5A gene are the only established cause of Brugada syndrome. Comprehensive analysis of all reported genetic alterations identified the origin of disease in no more than 40% of diagnosed cases. Therefore, identifying the cause of this rare arrhythmogenic disease in the many families without a genetic diagnosis is a major current challenge in Brugada syndrome. Additional challenges are interpretation/classification of variants and translation of genetic data into clinical practice. Further studies focused on unraveling the pathophysiological mechanisms underlying the disease are needed. Here we provide an update on the genetic basis of Brugada syndrome.

Keywords: Brugada syndrome; arrhythmias; genetics; sudden cardiac death.

Figure 1

Genetics of Brugada syndrome (BrS). After a comprehensive genetic analysis, almost 60% of patients remain without a genetic diagnosis. No more than 35% of cases are due to rare variants; of them, almost 30% are located in the SCN5A gene. Other alterations such as copy number variants, variants in regulatory regions and common variants are responsible altogether for less than 10% of BrS cases.