Common genetic variants in sudden cardiac death.

Evidence from family history, twin studies and molecular studies of rare inherited arrhythmia predisposition syndromes indicate that genetic factors are important contributors to determining risk for sudden cardiac death (SCD). More recent evidence indicates that common genetic variants in several genes can explain part of this risk at the population level. Here, the genetic risks for SCD are reviewed along with explanations of basic concepts relevant to understanding genetic contributions to common diseases. Also reviewed are two categories of genetic studies that have led to important discoveries about the genetic basis for SCD in general populations. Candidate gene studies focusing mainly on genes responsible for rare inherited arrhythmia susceptibility syndromes or on determinants of autonomic nervous system function will be highlighted first followed by more recent data from genome wide association studies that have identified previously unrecognized genomic intervals that explain inter-individual differences in QT interval duration possibly accounting for a proportion of the population-attributable risk for SCD.