Dilated cardiomyopathy is a heterogeneous entity that leads to heart failure and malignant arrhythmias. Nearly 50% of cases are inherited; therefore, genetic analysis is crucial to unravel the cause and for the early identification of carriers at risk. A large number of variants remain classified as ambiguous, impeding an actionable clinical translation. Our goal was to perform a comprehensive update of variants previously classified with an ambiguous role, applying a new algorithm of already available tools. In a cohort of 65 cases diagnosed with dilated cardiomyopathy, a total of 125 genetic variants were classified as ambiguous. Our reanalysis resulted in the reclassification of 12% of variants from an unknown to likely benign or likely pathogenic role, due to improved population frequencies. For all the remaining ambiguous variants, we used our algorithm; 60.9% showed a potential but not confirmed deleterious role, and 24.5% showed a potential benign role. Periodically updating the population frequencies is a cheap and fast action, making it possible to clarify the role of ambiguous variants. Here, we perform a comprehensive reanalysis to help to clarify the role of most of ambiguous variants. Our specific algorithms facilitate genetic interpretation in dilated cardiomyopathy.

A conclusive and early diagnosis of cardiomyopathy is essential for implementing preventive therapeutic measures and, therefore, reducing the risk of malignant arrhythmias and even sudden cardiac death. Occasionally, this lethal event can be the first manifestation of cardiomyopathy, with or without a clear structural defect. In cases of sudden death, especially in young patients, the autopsy may be ambiguous and therefore lack a definitive diagnosis of cardiomyopathy, although it can sometimes identify signs that lead us to suspect it. This is one of the current challenges of forensic science, where occult cardiomyopathies often remain unidentified without additional testing that is not routinely included in current forensic protocols. In this protocol, it is crucial to perform a molecular autopsy but also to include additional data, especially family history, that will help conclude or at least suspect this entity. Obtaining this diagnosis or suspicion of concealed cardiomyopathy not only provides an answer to the unexpected death but also helps the relatives determine the cause of death. In addition, physicians should initiate a family assessment to identify other family members who may be at risk early and adopt personalized preventive measures.