Hereditary non-structural diseases such as catecholaminergic polymorphic 
ventricular tachycardia (CPVT), long QT, and the Brugada syndrome as well as 
structural disease such as hypertrophic cardiomyopathy (HCM) and arrhythmogenic 
right ventricular cardiomyopathy (ARVC) cause a significant percentage of sudden 
cardiac deaths in the young. In these cases, genetic testing can be useful and 
does not require proxy consent if it is carried out at the request of judicial 
authorities as part of a forensic death investigation. Mutations in several 
genes are implicated in arrhythmic syndromes, including SCN5A, KCNQ1, KCNH2, 
RyR2, and genes causing HCM. If the victim's test is positive, this information 
is important for relatives who might be themselves at risk of carrying the 
disease-causing mutation. There is no consensus about how professionals should 
proceed in this context. This article discusses the ethical and legal arguments 
in favour of and against three options: genetic testing of the deceased victim 
only; counselling of relatives before testing the victim; counselling restricted 
to relatives of victims who tested positive for mutations of serious and 
preventable diseases. Legal cases are mentioned that pertain to the duty of 
geneticists and other physicians to warn relatives. Although the claim for a 
legal duty is tenuous, recent publications and guidelines suggest that 
geneticists and others involved in the multidisciplinary approach of sudden 
death (SD) cases may, nevertheless, have an ethical duty to inform relatives of 
SD victims. Several practical problems remain pertaining to the costs of 
testing, the counselling and to the need to obtain permission of judicial 
authorities.