In about 10% of cases, sudden cardiac death (SCD) in young people is due to a cardiac gene defect. This was the conclusion drawn by Silke Kauferstein of the Department of Forensic Medicine of the Johann Wolfgang Goethe University, Frankfurt, and her coauthors in the current Deutsches Ärzteblatt International (Dtsch Arztebl Int 2009; 106(4): 41-7).
Sudden cardiac death is defined as unexpected death occurring rapidly—usually within 1 h of the onset of symptoms—in persons who had previously seemed to be healthy. It is one of the most frequent causes of death in Europe. Each year, about 100 000 people die of sudden cardiac death in Germany alone. Although SCD mostly affects older people, 5% to 15% of cases are in young people who had previously been asymptomatic.
Most cases of sudden cardiac death can be explained by cardiovascular changes. However, in 10% to 30% of cases, no cause of death can be established, even after a postmortem. Genetically linked diseases of cardiac ion channels are responsible for at least a third of these deaths. As the ion channels are involved in stimulation and conduction in the heart, malfunction can cause cardiac arrythmias, which may lead to ventricular fibrillation.
These primary electrical heart disorders are mostly subject to autosomal dominant inheritance. This means that family members have a 50% risk of being carriers of the modified gene causing the disorder. A genetic study of the affected family is therefore essential if further cases of sudden cardiac death are to be prevented.