Sudden Cardiac Death in Children and Young Adults

To the Editor: The findings of Bagnall et al. (June 23 issue) 1 about the role of genetic testing in cases of sudden cardiac death deserve comment. The high incidence of cases of sudden cardiac death in children 1 to 5 years of age that were classified as unexplained (37 of 49 cases) is problematic. Moreover, genetic testing did not help to identify a cause in most of these cases. According to Table S11 in the Supplementary Appendix of the article (available with the full text of the article at NEJM.org), a likely pathogenic variant was identified in only 6 of . . .