Scientists at the Wales Heart Research Institute, Cardiff University have made a breakthrough in our understanding of the causes of sudden cardiac death (SCD) in young people. This research has been funded by the British Heart Foundation. SCD is a major cause of mortality worldwide, and when it occurs in young children and adolescents is particularly devastating. Daniel Yorath, son of former Wales soccer team manager, Terry, is amongst those to have suffered sudden cardiac death. Recent advances have shown that the genetic mutations in the heart’s calcium release channels (known as ryanodine receptors) destroy the ability of the channels to work properly following stress or exercise. These channels released too much calcium, possibly explaining how in affected young people, the normal heart signalling is severely disrupted and could lead to fatally high heart rates (tachycardia) and a loss of co-ordinated heart rhythm (arrhythmia). Despite these advances, pinpointing the changes that occur within the mutant channel molecules that cause the increase in calcium release remained elusive. These new insights show that normal channels open and close in a tightly regulated fashion, but that mutations make the activated channels ‘jittery’ and prevent them from closing properly. The research is published online in Circulation Research 8 December 2005 and in print 6 January 2006.