To prevent sudden death in m.3243A>G carriers, comprehensive neurologic, cardiac, and pulmological examinations are required.

The interesting study has limitations that put the results and their interpretation into perspective. m.3243A>G carriers should undergo prospective testing for multisystem disease to avoid missing subclinical multisystem involvement. m.3243A>G carriers with hypertrophic cardiomyopathy require long-term electrocardiogram recordings to determine whether implantable cardioverter defibrillator implantation is necessary or not. To assess the outcome of m.3243A>G carriers, knowledge of heteroplasmy rates and mtDNA copy numbers is required. It is tempting to assign pathogenicity when any pathogenic variant is seen with genotype-phenotype correlation. However, double hits are possible and if genetic information is to be used to screen or risk-stratify other family members, the standard of care would be to ensure that post-mortem genetic autopsy is performed for a panel of causative genes, and that an autopsy is done to exclude other causes of death, if possible.