An international team led by researchers from Duke University Medical Center and the Howard Hughes Medical Institute (HHMI) have defined a previously undescribed inherited cardiac arrhythmia syndrome that can lead to sudden death and can strike young, seemingly healthy people. After discovering in 2003 a mutation in a specific gene in an extended French family for the arrhythmia, the researchers have identified four other similar mutations in different families worldwide, adding further evidence that they have indeed identified a new cardiac arrhythmia syndrome. The gene in question -- ankyrin-B -- encodes a protein that coordinates ion channels and transporters and thus regulates the flow of ions in and out of heart muscle cells, which in turn controls the beating of the heart.