Outcomes of post mortem genetic diagnosis in SCD victims and primary prevention of cardiac arrest in relatives: a nationwide multidisciplinary and multicentric collaboration in the Czechia
Authors: Krebsova A , Votypka P , Peldova P , Rucklova K , Kulvajtova M , Pohlova -Kucerova S , Pilin A , Gregorova A , Tavacova T , Petrkova J , Dobias M , Tomasek P , Macek Jr M , Janousek J , Kautzner J 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health of the Czech Republic

Introduction
Post mortem genetic analysis in sudden cardiac death (SCD) represents an important diagnostic tool for the primary prevention of cardiac arrest in victim´s relatives.

Purpose
To assess the underlying molecular pathogenesis of SCD in a representative Czech cohort and to evaluate the effects of primary prevention of SCD in genetic relatives.

Patients and Methods
Between 2016 and 2020 we have ascertained 100 SCD cases (29 females/71 males; age range 0-52 years). According to autopsy protocols, cases with SCD were divided into categories of sudden arrhythmic death (SADS), sudden unexplained death (in infants; SUD/SUDI), thoracic aortic aneurysm/dissection and cardiomyopathy hypertrophic, arrhythmic, dilated (HCM, ACM, DCM) and sudden infant death syndrome (SIDS). DNA was isolated from post mortem biopsies / relatives blood and subjected to massively parallel sequencing (Illumina, USA) comprising custom-made candidate gene panel (100 genes). Genetic counselling and cardiological examinations were carried out in 245 family members.

Results
According to post mortem-established diagnosis, we identified 20 victims with SADS and SUD/SUDI, 11 with HCM and DCM, 19 with ACMG, 8 SIDS cases and 9 acute dissection cases. Most of victims died at sleep or at rest, while only 10/100 victims died during strenuous sport activities. About 50% of SCD victims did not report any apparent cardiac complaints. Highly likely or certain molecular etiology (i.e. based on presence of ACMG.net Class 4 to 5 variants) was disclosed in 19/100 (19%) in RYR2, KCNH2, SCN5A, FLNC (stop), TTN, RBM 20, LMNA/C, PRKAG2, MYBPC3, DSC2, FHL1, TGFBR1 and Col3A1 genes (see Tab). Finally, we identified 52/241 phenotype/genotype positive family members who are at risk of cardiac arrest and were offered corresponding cardiological care.

Conclusion
Multidisciplinary cooperation, together with centralized and standardized molecular genetic testing, enables the primary prevention of cardiac arrest in relatives of SCD victims.
Results of post mortem genetic analysis Post mortem diagnosis Nr. Gender Age (years) Nr. of positive cases (DNA variant class IV or V) Gene Nr. examined relatives/phenotype or genotype positive cases SADS 20 8 females12 males 3-52 5/20 (25%) KCNH2 3x RYR2RANGFR 56/11 SUD/SUDI 20 5 females, 15 males 0-50 1/18 (5%, 2 non informative cases) RYR2 45/9 HCM 11 0 females11 males 14-52 3/11 (27%) MYBPC3FHL1PRKAG2 26/9 DCM 11 3 females8 males 8-48 4/11 (36%) TTN (3x)RBM 20FLNC (stop) 24/7 ACM 19 9 females10 males 17 - 49 4/19 (21%) SCN5AFLNC (stop)DSC2LMNA/C 58/9 SIDS 8 3 females5 males &lt; 1 0/8 - 12/0 Acute dissection 9 1 female8 males 16-49 2/9 (22%) TGFBR1Col3A1 24/7