Postmortale molekulargenetische Untersuchungen (molekulare Autopsie) bei kardiovaskulären und bei ungeklärten Todesfällen

[Cardiogenetics in Germany- a view and review]

The development of the cardiogenetics field in Germany has been increasing since the mid-1990s with many national contributions, some of them were really important and groundbreaking. The starting point was and still is the patient and his family, e.g. with a familial form of arrhythmia or cardiomyopathy, the clarification of the genetic cause and the personalized treatment of those being affected. The scientific, always translationally oriented interest in identifying a causative gene and uncovering the underlying pathomechanisms has led to notable contributions for Brugada syndrome, short QT syndrome and cardiac conduction disorders or sinus node dysfunction, but also in DCM or ARVC. What is important, however, is always the way back (bench > bed side): implementation of national and international recommendations for cardiogenetic diagnostics in daily cardiological routine and the personalized care and therapy of those being affected.

[Postmortem genetic analysis following sudden cardiac death : Background, approach, and future]

BACKGROUND

Sudden cardiac death (SCD) is defined as an unexpected, nontraumatic death with a possible cardiac or unknown cause. The lowest incidence is observed in infancy and childhood (1 per 100,000), and the incidence is approximately 50 per 100,000 in the middle-aged population, reaching a plateau around the age of 80 (200 per 100,000). While most SCD cases occur in older people with coronary artery disease, there is a predominance of monogenetic and polygenetic diseases in the young.

METHODS

Postmortem genetic analysis (molecular autopsy) using next-generation sequencing reveals a definite pathogenic genetic alteration, which can explain SCD of young patients in near 20% of the cases. Hence, postmortem genetic analysis has become an important tool to unravel the inheritable cause of death. Furthermore, early identification of a pathogenic genetic sequence variant in the deceased is crucial to reduce risk in relatives due to preventive personalized measures.

RESULTS AND CONCLUSION

Postmortem genetic analysis forms together with the clinical assessment the basis for early identification of at-risk relatives. A new guideline for the management of ventricular arrhythmias and prevention of sudden death was recently published by the European Society of Cardiology. The new recommendations give genetic testing, also in deceased patients a much higher priority reflecting increasing relevance of genetic testing for diagnostic evaluation, risk stratification and prevention.

[Genetic testing in daily clinical practice according to the guidelines : How do we proceed?]

Genetic testing and counselling has become a fundamental part of the diagnostic work-up and risk stratification in ion channel diseases. The diagnostic yield varies among the different entities. For the most common diseases, there is a class I recommendation for the initiation of genetic testing and counseling. The German law for genetic diagnostics defines all steps of the pathway in detail. In clinical practice, coordination of the different levels of clinical guidance and genetic diagnostics and testing poses a logistic challenge. Involving human geneticists in the procedure is mandatory. For predictive genetic testing, human genetic counseling is mandatory before initiation of the testing and after obtaining the results. As far as causality of genetic variants for the arrhythmic phenotypes is concerned, repeated curations are undertaken to avoid misinterpretation and overdiagnosis.

Legal aspects of genetic testing in the evaluation of ventricular tachycardias

There is increasing knowledge of the genetic basis of distinct cardiac pathologies that are related to ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). The identification of genes responsible for inherited cardiac diseases has led to the organization of cardiogenetic consultations in many countries worldwide. The 2022 European Society of Cardiology (ESC) guidelines for the management of patients with ventricular arrhythmias and the prevention of SCD and the international 2022 Expert Consensus Statement on the state of genetic testing for cardiac diseases emphasize the importance of genetic testing in cardiology practice along with appropriate information provision to affected individuals and their relatives. However, the context of genetic examination raises particular ethical, practical (including economic or financial), and legal challenges. This review aims to elucidate practical considerations related to legal aspects relevant for the evaluation of patients presenting with VT in Germany.

The emergency medical service has a crucial role to unravel the genetics of sudden cardiac arrest in young, out of hospital resuscitated patients: Interim data from the MAP-IT study

BACKGROUND

Genetics of sudden cardiac deaths (SCD) remains frequently undetected. Genetic analysis is recommended in undefined selected cases in the 2021 ERC-guideline. The emergency medical service and physicians (EMS) may play a pivotal role for unraveling SCD by saving biomaterial for later molecular autopsy. Since for high-throughput DNA-sequencing (NGS) high quality genomic DNA is needed. We investigated in a prospective proof-of-concept study the role of the EMS for the identification of genetic forms of SCDs in the young.

METHODS

We included patients aged 1-50 years with need for cardiopulmonary resuscitation attempts (CPR). Cases with non-natural deaths were excluded. In two German counties with 562,904 residents 39,506 services were analysed. Paired end panel-sequencing was performed, and variants were classified according to guidelines of the American College of Medical Genetics (ACMG).

RESULTS

769 CPR-attempts were recorded (1.95% of all EMS-services; CPR-incidence 68/100,000). In 103 cases CPR were performed in patients < 50y. 58% died on scene, 26% were discharged from hospital. 24 subjects were included for genotyping. Of these 33% died on scene, 37.5% were discharged from hospital. 25% of the genotyped patients were carriers of (likely) pathogenic (ACMG-4/-5) variants. 67% carried variants with unknown significance (ACMG-3). 2 of them had familial history for arrhythmogenic cardiomyopathy or had to be re-classified as ACMG-4 carriers due to whole exome sequencing.

CONCLUSION

The EMS contributes especially in fatal OHCA-cases to increase the yield of identified genetic conditions by collecting a blood sample on scene. Thus, the EMS can contribute significantly to primary and secondary prophylaxis in affected families.