Molecular autopsy in young sudden cardiac death victims with suspected cardiomyopathy
Introduction
Sudden cardiac death (SCD) constitutes one of the most important unsolved challenges in the practice of forensic pathology. Several researchers have found that most sudden unexplained deaths (SUD) are caused by hereditary conditions of which cardiovascular diseases are the most frequent [1], [2], [3]. These conditions are genetically heterogeneous, making diagnosis and counselling difficult, with the risk of repeated sudden deaths in the same family. Incidence rates of SCD among persons aged 1–35 years, upon autopsy, were recently found to be 1.1 per 100,000 in a Danish study [4]. In this study, we present a genetic examination of structural heart diseases, which include cardiomyopathies, such as hypertrophic, dilated and arrhythmogenic right ventricle cardiomyopathy (HCM, DCM and ARVC), in a group of SCD in children and young adults. Most often, these inherited cardiac disorders give rise to lethal ventricular arrhythmias without any previous pathological clinical history and they show an autosomal dominant pattern of inheritance. Genetic screening of the major genes involved in cardiomyopathies can help determine the cause of death and may help to evaluate the potential risk of relatives. Table 1 summarises the most commonly studied genes associated with cardiomyopathies included in this study. Several other genes have been studied and found associated with cardiomyopathies, especially hypertrophic- and dilated cardiomyopathies, but with a minor frequency in patients. We performed molecular genetic studies on a selected group of the major genes associated with hereditary cardiomyopathies using blood samples from deceased persons suspected of cardiomyopathies based on autopsy findings.
Section snippets
Study subjects
The study material for the genetic screening of the major genes associated with cardiomyopathies (HCM, DCM, and ARVC) consisted of 41 cases with structural changes related to cardiomyopathies, aged 0–40 years that died in the period 1998–2007. DNA was obtained from post-mortem blood and stored at −80 °C. The material was selected from our own database by age (0–40 years) and cause of death (cardiovascular or an unknown cause of death at autopsy), and a manual selection of cases was then
Bioinformatics analyses
We aligned sequence traces to JUP (NM_002230.2), DSP (NM_004415.2), PKP2 (NM_004572.2), DSG2 (NM_001943.2), DCS2 (NM_004949.2), TMEM43 (NM_024334.2), MYH7 (NM_000257.2), MYBPC3 (NM_000256.3), and LMNA (NM_170707.2) reference sequences using SeqScape version 2.5 or 2.7 (Applied Biosystems). All variants were queried in gene specific mutation databases (http://www.arvcdatabases.info and http://lovd.nl/2.0/). Sequence variants leading to amino acid substitutions were evaluated using the PolyPhen 2
HCM, DCM, and HCM–DCM groups
Samples considered included 27 autopsy cases (21 male/6 female; aged 9–40 years), with structurally changes related to HCM and DCM (Fig. 1). We found that four of the 27 deceased had a rare sequence variant in the LMNA-, MYH7- or MYBPC3 genes. All presumed pathogenic mutations (p) are summarised in Table 2 (case; p1–p4), and presumed benign mutations (b) are summarised in Table 3 (case; b1–b5).
Case p1; had a rare sequence variant in the LMNA gene (p.R471H). Case p2; had a rare sequence variant
Discussion
We found that 9 of 41 cases (22%) with structural changes related to cardiomyopathies had a rare sequence variant in the LMNA, MYBPC3, MYH7, PKP2 or TMEM43 genes, of which 4 cases (9.8%) were suspected to be pathogenic changes (Fig. 1). The suspected pathogenic mutations were found in 1 case (p1) of suspected DCM (LMNA; p.R471H), 1 case (p2) of suspected HCM and DCM (MYH7; p.R442H) and 2 cases (p3–p4) of suspected ARVC (PKP2; p.R79X and LMNA; p.R644C). All 4 variants (p1–p4) have previously
Conclusion
In this SCD cohort, 22% had a rare sequence variant in the LMNA, MYBPC3, MYH7, PKP2 or TMEM43 genes, and 9.8% were suspected to be pathogenic variants. When SCD appears in younger people with structural anomalies of the heart, autopsy investigation including molecular autopsy will contribute to establish the cause of death. These results will subsequently be important in the risk stratification management and the genetic counselling of family members.
Conflict of interest
None declared.
Acknowledgements
This work was supported by Research Grants from the Jørgen Møllers Foundation, the Augustinus Foundation, the Grosserer A. V. Lykfeldt and Wife Foundation, the Helga and Peter Kornings Foundation, the Grosserer Valdemar Foersom and Thyra Foersom Foundation, and Aarhus University. The authors are grateful to Anette Stenderup, Gitte Glistrup Nielsen, Anette Funder and Jakob Hansen for excellent technical assistance.
References (23)
- et al.
Molecular genetics of sudden cardiac death
Forensic Sci. Int.
(2008) - et al.
Lamin A/C mutation analysis in a cohort of 324 unrelated patients with idiopathic or familial dilated cardiomyopathy
Am. Heart J.
(2008) - et al.
Characterization of the molecular phenotype of two arrhythmogenic right ventricular cardiomyopathy (ARVC)-related plakophilin-2 (PKP2) mutations
Heart Rhythm
(2008) - et al.
Clinical features and outcome of hypertrophic cardiomyopathy associated with triple sarcomere protein gene mutations
J. Am. Coll. Cardiol.
(2010) - et al.
New technologies in the genetic approach to sudden cardiac death in the young
Forensic Sci. Int.
(2010) - et al.
State of the art in forensic investigation of sudden cardiac death
Am. J. Forensic Med. Pathol.
(2011) - et al.
Postmortem diagnosis in sudden cardiac death victims: macroscopic, microscopic and molecular findings
Cardiovasc. Res.
(2001) - et al.
Nationwide study of sudden cardiac death in persons aged 1–35 years
Eur. Heart J.
(2010) - et al.
Guidelines for autopsy investigation of sudden cardiac death
Virchows Arch.
(2008) - http://www.ncbi.nlm.nih.gov/projects/SNP/....
Cited by (24)
Autopsy: Molecular
2015, Encyclopedia of Forensic and Legal Medicine: Second EditionArrhythmogenic Right Ventricular Cardiomyopathy Post-Mortem Assessment: A Systematic Review
2024, International Journal of Molecular SciencesMorphological and Genetic Aspects for Post-Mortem Diagnosis of Hypertrophic Cardiomyopathy: A Systematic Review
2024, International Journal of Molecular SciencesGenomic Autopsy of Sudden Deaths in Young Individuals
2021, JAMA CardiologyGenetic investigations of 100 inherited cardiac disease-related genes in deceased individuals with schizophrenia
2021, International Journal of Legal MedicineClinical impact of post-mortem genetic testing in cardiac death and cardiomyopathy
2020, Open Medicine (Poland)