Sudden unexpected deaths often remain unresolved despite forensic examination, posing challenges for pathologists. Molecular autopsy, through genetic testing, can reveal hidden causes undetectable by standard methods. This review assesses the role of molecular autopsy in clarifying SUD cases, examining its methodology, utility, and effectiveness in autopsy practice. This systematic review followed PRISMA guidelines and was registered with PROSPERO (registration number: CRD42024499832). Searches on PubMed, Scopus, and Web of Science identified English studies (2018-2023) on molecular autopsy in sudden death cases. Data from selected studies were recorded and filtered based on inclusion/exclusion criteria. Descriptive statistics analyzed the study scope, tissue usage, publication countries, and journals. A total of 1759 publications from the past 5 years were found, with 30 duplicates excluded. After detailed consideration, 1645 publications were also excluded, leaving 84 full-text articles for selection. Out of these, 37 full-text articles were chosen for analysis. Different study types were analyzed. Mutations were identified in 17 studies, totaling 47 mutations. Molecular investigations are essential when standard exams fall short in determining sudden death causes. Expertise in molecular biology is crucial due to diverse genetic conditions. Discrepancies in post-mortem protocols affect the validity of results, making standardization necessary. Multidisciplinary approaches and the analysis of different tissue types are vital.

Background Inborn errors of metabolism (IEM) are collectively rare but potentially preventable causes of sudden unexpected death (SUD) in infancy or childhood, and metabolic autopsy serves as the final tool for establishing the diagnosis. We conducted a retrospective review of the metabolic and molecular autopsy on SUD and characterized the biochemical and genetic findings. Methodology A retrospective review of postmortem metabolic investigations (dried blood spot acylcarnitines and amino acid analysis, urine metabolic profiling where available, and next-generation sequencing on a panel of 75 IEM genes) performed for infants and children who presented with SUD between October 2016 and December 2021 with inconclusive autopsy findings or autopsy features suspicious of underlying IEM in our locality was conducted. Clinical and autopsy findings were reviewed for each case. Results A total of 43 infants and children aged between zero days to 10 years at the time of death were referred to the authors\' laboratories throughout the study period. One positive case of multiple acyl-CoA dehydrogenase deficiency was diagnosed. Postmortem reference intervals for dried blood spot amino acids and acylcarnitines profile were established based on the results from the remaining patients. Conclusions Our study confirmed the importance of metabolic autopsy and the advantages of incorporating biochemical and genetic testing in this setting.

Investigating the causes of Sudden cardiac death (SCD) is always difficult; in fact, genetic cardiac conditions associated with SCD could be \"silent\" even during autopsy investigation. In these cases, it is important to exclude other aetiology and assist to ask for genetic investigations. Herein, the purpose of this review is to collect the most-implicated genes in SCD and generate a panel with indications for first line and second line investigations. A systematic review of genetic disorders that may cause SCD in the general population was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We subsequently listed the genes that may be tested in the case of sudden cardiac death when the autopsy results are negative or with no evidence of acquired cardiac conditions. To make genetic tests more specific and efficient, it is useful and demanded to corroborate autopsy findings with the molecular investigation as evident in the panel proposed. The genes for first line investigations are HCM, MYBPC3, MYH7, TNNT2, TNNI3, while in case of DCM, the most implicated genes are LMNA and TTN, and in second line for these CDM, ACTN2, TPM1, C1QPB could be investigated. In cases of ACM/ARVC, the molecular investigation includes DSP, DSG2, DSC2, RYR2, PKP2. The channelopathies are associated with the following genes: SCN5A, KCNQ1, KCNH2, KCNE1, RYR2. Our work underlines the importance of genetic tests in forensic medicine and clinical pathology; moreover, it could be helpful not only to assist the pathologists to reach a diagnosis, but also to prevent other cases of SCD in the family of the descendant and to standardise the type of analysis performed in similar cases worldwide.

BACKGROUND: Few reports describe the yield of postmortem genetic testing from medical examiners\' offices or correlate genetic test results with autopsy-confirmed phenotypes from a large cohort.
OBJECTIVE: To report results from cardiomyopathy- and cardiac arrhythmia-associated genetic testing in conjunction with autopsy findings of cases investigated at the United States\' largest medical examiner office.
METHODS: Postmortem cases tested from 2015 to 2022 with a cardiomyopathy- and cardiac arrhythmia-associated gene panel were reviewed. American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines were used to classify variant pathogenicity. Correlations of pathogenic/likely pathogenic variants (P/LPVs) with cardiac pathology were evaluated.
RESULTS: The cohort included 1107 decedents of diverse ages and ethnicities. P/LPVs were detected in 87 (7.9%) cases, with 73 and 14 variants in cardiomyopathy and cardiac arrhythmia genes, respectively. Variants of uncertain significance were detected in 437 (39.5%) cases. The diagnostic yield (percentage of P/LPV) in decedents with cardiomyopathy (26.1%) was significantly higher than those without (P<.0001). The diagnostic yield was significantly lower in infants (0.7%) than older age groups (ranging from 1 to 74 years old, 5.7%-25.9%), which had no statistical difference between their yields. The diagnostic yields by cardiac autopsy findings were 54.0% for hypertrophic cardiomyopathy, 47.1% for arrhythmogenic cardiomyopathy, 20.0% for myocardial fibrosis, 19.0% for dilated cardiomyopathy, and 11.3% for myocarditis. Most P/LPVs were in MYBPC3, TTN, PKP2, SCN5A, MYH7, and FLNC. Ten P/LPVs were novel.
CONCLUSIONS: Our results support the importance of performing postmortem genetic testing on decedents of all ages with cardiomyopathy, cardiac lesions insufficient to diagnosis a specific cardiomyopathy (e.g., myocardial fibrosis), and myocarditis. Combined postmortem cardiac examination and genetic analysis are advantageous in accurately determining the underlying cause of death and informing effective clinical care of family members.

Sudden cardiac death (SCD) is defined as unexpected death due to a cardiac cause that occurs rapidly. Despite the identification of prevention strategies, SCD remains a serious public health problem worldwide, accounting for 15-20% of all deaths, and is therefore a challenge for modern medicine, especially when it affects young people. Sudden cardiac death in young people affects the population aged ≤ 35 years, including athletes and non-athletes, and it is due to various hereditary and non-hereditary causes. After an autopsy, if the cause remains unknown, it is called sudden unexplained death, often attributable to genetic causes. In these cases, molecular autopsy-post-mortem genetic testing-is essential to facilitate diagnostic and therapeutic pathways and/or the monitoring of family members of the cases. This review aims to elaborate on cardiac disorders marked by genetic mutations, necessitating the post-mortem genetic investigation of the deceased for an accurate diagnosis in order to facilitate informed genetic counseling and to implement preventive strategies for family members of the cases.

BACKGROUND: Inherited cardiomyopathies (HCM, DCM, ACM) and cardiac ion channelopathies (long QT/Brugada syndromes, CPVT) are associated with significant morbidity and mortality; however, diagnosis of a familial pathogenic variant in a proband allows for subsequent cascade screening of their at-risk relatives.
OBJECTIVE: We investigated the diagnostic yield from cardiac gene panel testing and reviewed variants of uncertain significance from patients attending three specialist cardiogenetics services in Ireland in the years 2002 to 2020.
RESULTS: Reviewing molecular genetic diagnostic reports of 834 patients from 820 families, the initial diagnostic yield of pathogenic/likely pathogenic variants was 237/834 patients (28.4%), increasing to 276/834 patients (33.1%) following re-evaluation of cases with variant(s) of uncertain significance. Altogether, 42/85 patients with VUS reviewed (49.4%) had a re-classification that could change their clinical management. Females were more likely to carry pathogenic/likely pathogenic variants than males (139/374, 37.2% vs 137/460, 29.8%, respectively, p = 0.03), and the diagnostic yields were highest in the 0 to < 2 years age group (6/12, 50.0%) and amongst those tested for cardiomyopathy gene panels (13/35, 37.1%). Variants in the MYBPC3/MYH7 (87/109, 79.8%) and KCNQ1/KCNH2 (91/100, 91.0%) genes were the predominant genetic causes for hypertrophic cardiomyopathy and long QT syndrome, respectively.
CONCLUSIONS: Our study highlights the importance of collation and review of pre-ACMG genetic variants to increase diagnostic utility of genetic testing for inherited heart disease. Almost half of patients with pre-ACMG VUS reviewed had their variant re-classified to likely pathogenic/likely benign which resulted in a positive clinical impact for patients and their families.

Sudden unexpected death in the young (SUDY) is a traumatic occurrence for their family; however, information on the genetic variations associated with the condition is currently lacking. It is important to carry out postmortem genetic analyses in cases of sudden death to provide information for relatives and to allow appropriate genetic counselling and clinical follow-up. This study aimed to investigate the genetic variations associated with the occurrence of SUDY in Japan, using next-generation sequencing (NGS). The study included 18 cases of SUDY (16 males, 2 females; age 15-47 years) who underwent autopsy, including NGS DNA sequencing for molecular analysis. A total of 168 genes were selected from the sequencing panel and filtered, resulting in the identification of 60 variants in cardiac disease-related genes. Many of the cases had several of these genetic variants and some cases had a cardiac phenotype. The identification of genetic variants using NGS provides important information regarding the pathogenicity of sudden death.

OBJECTIVE: Sudden cardiac death (SCD) may occur in apparently healthy individuals, including athletes. The aim was to investigate the diagnostic role of post-mortem genetic testing, molecular autopsy (MA), in elucidating the cause of SCD in athletes.
RESULTS: We reviewed a database of 6860 consecutive cases of SCD referred to our specialist cardiac pathology centre. All cases underwent detailed cardiac autopsy, and 748 were deemed to be athletes. Of these, 42 (6%) were investigated with MA (28 using a targeted sequencing, 14 exome sequencing). Variants were classified as pathogenic, likely pathogenic, or variant of unknown significance using international guidelines. Clinical information was obtained from referring coroners who completed a detailed health questionnaire. Out of the 42 decedents (average age 35 years old, 98% males) who were investigated with MA, the autopsy was in keeping with a structurally normal heart [sudden arrhythmic death syndrome (SADS)] in n = 33 (78%) cases, followed by arrhythmogenic cardiomyopathy (ACM) in eight (19%) individuals and idiopathic left ventricular fibrosis in one (2%). Death occurred during exercise and at rest in 26 (62%) and 16 (38%) individuals, respectively. Variants that were adjudicated clinically actionable were present in seven cases (17%). There was concordance between the genetic and phenotypic findings in two cases of ACM (in FLNC and TMEM43 genes). None of the variants identified in SADS cases were previously linked to channelopathies. Clinically actionable variants in cardiomyopathy-associated genes were found in five cases of SADS.
CONCLUSIONS: The yield of MA in athletes who died suddenly is 17%. In SADS cases, clinically actionable variants were found in cardiomyopathy-associated genes and not in channelopathy-associated genes. Arrhythmogenic cardiomyopathy is a common cause of SCD in athletes, and one in four decedents with this condition had a clinically actionable variant in FLNC and TMEM43 genes.

Japan has various death investigation systems; however, external examinations, postmortem computed tomography, macroscopic examinations, and microscopic examinations are performed regardless of the system used. These examinations can reveal morphological abnormalities, whereas the cause of death in cases with non-morphological abnormalities can be detected through additional examinations. Molecular autopsy and postmortem genetic analyses are important additional examinations. They are capable of detecting inherited arrhythmias or inherited metabolic diseases, which are representative non-morphological disorders that cause sudden death, especially in infants and young people. In this review, we introduce molecular autopsy reports from Japan and describe our experience with representative cases. The relationships between drug-related deaths and genetic variants are also reviewed. Based on the presented information, molecular autopsy is expected to be used as routine examinations in death investigations because they can provide information to save new lives.

The diagnosis of cardiomyopathy often relies on the subjective judgment of pathologists due to the variety of morphologic changes in the condition and its low specificity. This uncertainty can contribute to unexplained sudden cardiac deaths (USCD). To enhance the accuracy of hereditary cardiomyopathy diagnosis in forensic medicine, we proposed a combination of molecular autopsy and pathologic autopsy. By analyzing 16 deceased patients suspected of cardiomyopathy, using whole exome sequencing (WES) in molecular autopsy, and applying a combined diagnostic strategy, the study found pathogenic or likely pathogenic variants in 6 cases. Out of the 16 cases, cardiomyopathy was confirmed in 3, while 3 exhibited conditions consistent with it. Data for 4 cases was inconclusive, and cardiomyopathy was ruled out in 6. Notably, a novel variant of the TTN gene was identified. This research suggests that a grading diagnostic strategy, combining molecular and pathological evidence, can improve the accuracy of forensic cardiomyopathy diagnosis. This approach provides a practical model and strategy for precise forensic cause-of-death determination, addressing the limitations of relying solely on morphologic assessments in cardiomyopathy cases, and integrating genetic information for a more comprehensive diagnosis.