(Postmortem genetic testing in sudden cardiac death victims and genetic screening of relatives at risk in the Czech Republic)

Sudden cardiac death (SCD) in individuals younger than 40 years has a heritable cause in a significant subset of cases. Identification of SCD, postmortem genetic analysis along with the cardiological screening in first degree relatives represents an important tool for the primary prevention of cardiac arrest in victim's rela-tives and requires multicentric and multidisciplinary collaboration. Between 2016 and 2021 we dealt with totally 133 cases of sudden death, the complex cardiogenetic analysis was performed in 115 cases at the age of 0-59 years with post mortem diagnosis of cardiomyopathy, acute aortic dissection and cases without mor-phological finding explaining the cause of death (sudden arrhythmic death or sudden unexplained death). DNA was isolated from post mortem collected tissue samples or relative's blood and subjected to massively parallel sequencing (SophiaGenetics, Switzerland). Genetic counselling and cardiological examinations were carried out in 328 family members. Highly likely or certain molecular aetiology (i.e. based on presence of ACMG.net classification 4 to 5 variants) was disclosed in 19.8% of analysed cases in RYR2, KCNH2, KCNQ1, SCN5A, FLNC, GLA, TTN, TNNT2, RBM 20, MYBPC3, MYPN, FHL1, TGFBR1, and COL3A1 genes. With cardio-genetic screening we identified 83/328 (26.2%) relatives at risk of life threatening arrhythmias, who were offered individualised care.Conclusion: Our study with postmortem analysis could reveal a pathogenic DNA variant in 19.8% of cases and in 32.6% in cases with positive family history. A relevant number of studied victims had a positive family history, which indicates the importance of family cascade screening in patients with heart failure or malig-nant arrhythmias of unclear aetiology for primary prevention of sudden cardiac death.