Postmortem genetic testing should be recommended in sudden cardiac death cases due to thoracic aortic dissection

Reviewing hereditary connective tissue disorders: Proposals of harmonic medicolegal assessments

Hereditary connective tissue disorders (HCTDs) are a heterogeneous group of inherited diseases. These disorders show genetic mutations with loss of function of primary components of connective tissue, such as collagen and elastic fibers. There are more than 200 conditions that involve hereditary connective tissue disorders, while the most known are Marfan syndrome, Osteogenesis Imperfecta, and Ehlers-Danlos syndromes. These disorders need continuous updates, multidisciplinary skills, and specific methodologic evaluations sharing many medicolegal issues. Marfan syndrome and Ehlers-Danlos syndromes show a high risk of early sudden death. As a consequence of this, postmortem genetic testing can identify novel genotype-phenotype correlations which help the clinicians to assess personalized cardiovascular screening programs among the ill subjects. Genetic testing is also essential to identify children suffering from Osteogenesis Imperfecta, especially when a physical abuse is clinically suspected. However, this is a well-known clinical problem even though there are still challenges to interpret genetic data and variants of unknown significance due to the current extensive use of new genetic/genomic techniques. Additionally, the more significant applications and complexities of genomic testing raise novel responsibilities on the clinicians, geneticists, and forensic practitioners as well, increasing potential liability and medical malpractice claims. This systematic review provides a detailed overview on how multidisciplinary skills belonging to clinicians, medicolegal consultants, radiologists, and geneticists can cooperate to manage HCTDs from autopsy or clinical findings to genetic testing. Thus, technical aspects need to be addressed to the medicolegal community since there is no consensus works or guidelines which specifically discuss these issues.

Targeted genetic analysis in a cohort of sporadic death from spontaneous rupture of thoracic aortic dissection in Han Chinese population

PURPOSE

Thoracic aortic dissection (TAD) is a life-threatening cardiovascular disease that often results in sudden cardiac death (SCD). However, the genetic characteristics of individuals with TAD confirmed at autopsy have been rarely studied. Our objective was to determine the prevalence of pathogenic variants in TAD-associated genes in a cohort of sporadic deaths resulting from spontaneous rupture of TAD and identify relevant genotype-phenotype relationships in Han Chinese population.

METHODS

We included sixty-one consecutive sporadic decedents whose primary cause of death was spontaneous rupture of TAD, and performed a whole exome sequencing based strategy comprising 26 known TAD-associated genes.

RESULTS

We identified 7 pathogenic or likely pathogenic (P/LP) variants in 7 cases (11.48 %) and 22 variants of uncertain significance (VUS) in 22 cases (36.07 %). The FBN1 gene was found to be the major disease-causing gene. Notably, TAD decedents with P/LP variant exhibited significantly earlier mortality. Moreover, we reported for the first time that TAD decedents with P/LP variant had a shorter diagnosis and treatment time.

CONCLUSION

Our study investigated the genetic characteristics of TAD individuals confirmed until autopsy in Han Chinese population. The findings enhanced the understanding of the genetic underpinnings of TAD and have significant implications for clinical management and forensic investigations.

Thoracic Aortic Aneurysm and Dissection: Review and Recommendations for Evaluation

ABSTRACT

Aortic dissection and rupture (collectively termed "sudden aortic death") are commonly encountered by forensic pathologists, with an estimated incidence at autopsy between 0.6% and 7.7%. Despite this, there is no standard of practice for the evaluation of sudden aortic death at autopsy.Recent studies have shown 20% of patients with thoracic aortic aneurysm or dissection (TAAD) have an identifiable genetic syndrome, and 19% will have an affected first-degree relative. The past 2 decades have seen identification of new culprit genes and syndromes, which can have subtle or nonexistent external phenotypes. A high index of suspicion is warranted to identify possible hereditary TAAD (H-TAAD), allowing family members to obtain screening to avoid catastrophic vascular events. Forensic pathologists need broad knowledge of the spectrum of H-TAAD and awareness of the relative significance of hypertension, pregnancy, substance use, and microscopic changes of aortic architecture.This article reviews the common subtypes of H-TAAD, including Marfan syndrome, vascular Ehlers-Danlos, Loeys-Dietz, and familial thoracic aortic aneurysm and dissection. Recommendations for the evaluation of sudden aortic death at autopsy are presented, including (1) performance of a complete autopsy, (2) documentation of aortic circumference and valve morphology, (3) notifying family of the need for screening, and (4) preservation of a sample for potential genetic testing.

Applying multi-omics techniques to the discovery of biomarkers for acute aortic dissection

Acute aortic dissection (AAD) is a cardiovascular disease that manifests suddenly and fatally. Due to the lack of specific early symptoms, many patients with AAD are often overlooked or misdiagnosed, which is undoubtedly catastrophic for patients. The particular pathogenic mechanism of AAD is yet unknown, which makes clinical pharmacological therapy extremely difficult. Therefore, it is necessary and crucial to find and employ unique biomarkers for Acute aortic dissection (AAD) as soon as possible in clinical practice and research. This will aid in the early detection of AAD and give clear guidelines for the creation of focused treatment agents. This goal has been made attainable over the past 20 years by the quick advancement of omics technologies and the development of high-throughput tissue specimen biomarker screening. The primary histology data support and add to one another to create a more thorough and three-dimensional picture of the disease. Based on the introduction of the main histology technologies, in this review, we summarize the current situation and most recent developments in the application of multi-omics technologies to AAD biomarker discovery and emphasize the significance of concentrating on integration concepts for integrating multi-omics data. In this context, we seek to offer fresh concepts and recommendations for fundamental investigation, perspective innovation, and therapeutic development in AAD.

Genetic testing and clinical relevance of patients with thoracic aortic aneurysm and dissection in northwestern China

BACKGROUND

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening pathology that remains a challenge worldwide. Up to 40% of TAAD cases are hereditary with complex heterogeneous genetic backgrounds. The purposes of this study were to determine the diagnostic rate of patients with TAAD, investigate the molecular pathologic spectrum of TAAD by next-generation sequencing (NGS), and explore the future preclinical prospects of genetic diagnosis in patients at high -risk of study.

METHODS

NGS was used to screen 15 genes associated with genetic TAAD in 212 patients from northwestern China. Clinical data of patients were gathered by electrocardiography, transthoracic echocardiography, and computed tomography.

RESULTS

Of the 212 patients, 67 (31.60%) tested positive for a (likely) pathogenic variant, 42 (19.81%) had a variant of uncertain significance (VUS), and 103 (48.58%) had no variant (likely benign/benign/negative). A total of 135 reportable variants were detected in our test, among which 77 (57.04%) are first reported in this paper. A genotype-phenotype correlation of FBN1 was assessed, and the data showed that the patients with truncating and splicing mutations are more prone to developing severe aortic dissection than those with missense mutations, especially frameshift mutations (82.76% vs. 42.86%). In this study, 43 (20.28%) patients had a family history of sudden death or TAAD, whereas 132 (62.26%) did not (the remaining 37 were not available), and the positive rate of genetic testing was higher in TAAD patients with family history than in those without (76.74% vs. 18.94%).

CONCLUSION

Our study concludes that genetic variation is an important consideration in the risk stratification of individualized prediction and disease diagnosis.

Postmortem detection of COL gene family variants in two aortic dissection cases

Aortic dissection (AD) usually remains undiagnosed, but its manifestation is abrupt and is associated with high morbidity and poor prognosis, leading to sudden cardiac death. Variants in COL family genes are associated with AD. In case 1, a 32-year-old Chinese man was admitted to the hospital with complaints of abdominal pain and died on the next day. In case 2, a 36-year-old Chinese woman was admitted to the hospital because of waist pain and died the next afternoon. According to autopsy findings, the cause of death in both cases was an acute cardiac tamponade, which was attributed to AD rupture. Whole-exome sequencing was performed on the blood collected from the hearts of the two deceased patients. Positive variants in COL family genes were found in both cases, without positive variants in other AD-associated genes. In case 1, a novel, likely pathogenic, missense variant was identified in COL6A1. In case 2, we identified one novel, likely pathogenic, frameshift deletion in COL23A1 and one novel, likely pathogenic, missense mutation in COL1A2. Based on these two cases, physicians should consider the role and significance of COL family gene mutations in AD in young patients. Furthermore, molecular anatomy is clearly necessary and significant in cases of sudden cardiac death attributed to AD, particularly in younger individuals.

Exploring the genetic pathogenicity of aortic dissection from 72 Han Chinese individuals using next-generation sequencing

Aortic dissection (AD) is a heterogeneous genetic disease with high morbidity and mortality. Although many genes predispose patients to AD, the pathogenic spectrum remains incomplete. This study aims to (a) investigate whether genotype differences exist between Stanford A and B AD individuals, and (b) broaden the pathogenic genetic spectrum of AD and reported novel variants of AD-associated genes. The DNA of 72 unrelated Han Chinese individuals with AD was tested by whole-exome sequencing. Of 142 AD-associated genes, 10 pathogenic variants, and 48 likely pathogenic variants in 36 genes were identified among 39 cases. The diagnostic yield was 54.2%. Of the 58 positive variants, 27 were novel. FBN1 was the most frequently positive gene in both Stanford A and Stanford B. Twenty-seven positive variants from 18 COL family genes were distributed in 36.8% of Stanford A and 6.7% of Stanford B cases. We emphasize that positive variants of COL family genes show distribution predominance and strong pathogenicity in Stanford A, while positive variants of smooth muscle cell pathway genes present distribution advantages mainly in Stanford B cases. Our findings provide a new perspective for both the pathogenic mechanism and the treatment of AD.

Genetic testing in sudden unexpected natural death in the young: New York City Office of Chief Medical Examiner's experience and perspective

Postmortem genetic testing is a diagnostic tool that is becoming increasingly utilized. The benefits and limitations of genetic testing in cases of sudden, unexpected death in the young (≤ 40 years old) are reviewed from the perspective of the Office of Chief Medical Examiner of the City of New York, whose Molecular Genetics Laboratory, accredited by College of American Pathologists, has had 15 years of postmortem testing experience. Challenges to the interpretation and communication of testing results are highlighted, and opportunities for improving testing yield are discussed for age groups across the lifespan, from infancy to adulthood.

Sudden Death Due to Thoracic Aortic Dissection in Young People: A Multicenter Forensic Study

INTRODUCTION AND OBJECTIVES

Thoracic aortic dissection (TAD) is infrequent in young people and its characteristics differ from those in the adult population. This study aimed to analyze the clinical and pathological characteristics of sudden death due to TAD in people aged 1 to 35 years.

METHODS

Multicenter population-based study based on forensic autopsies conducted in the provinces of Biscay (1991-2016), Valencia (2000-2016), and Seville (2004-2016).

RESULTS

We identified 35 individuals with sudden death due to TAD (80% males), with a mean age of 29±5 years. The incidence was 0.09/100 000 inhabitants/y. Eighteen persons had at least 1 risk factor for TAD, and this figure increased to 29 when postmortem findings were included: congenital heart disease (n=16), suspicion of familial TAD (n=11), cocaine use (n=6), and hypertension (n=5). Twenty-four individuals, 12 with at least 1 risk factor, had prodromal symptoms, and 16 of them visited their physician, but TAD was not suspected in any of them. The most frequent symptom was chest pain (n=12). The main autopsy findings were cystic degeneration of the media (n=27), dilatation of the ascending aorta (n=21), cardiac hypertrophy (n=20), and bicuspid aortic valve (n=14).

CONCLUSIONS

The incidence of sudden death due to TAD in young people was very low. The most frequent risk factors were congenital heart disease followed by suspicion of familial TAD and cocaine use. TAD should be included in the differential diagnosis of chest pain in young people, mainly male patients with at least 1 risk factor.

Genetic diagnosis of acute aortic dissection in South China Han population using next-generation sequencing

Acute aortic dissection (AAD) is a clinically "silent," but emergent and life-threatening cardiovascular disease, and hereditary factors play an important etiologic role in the development of AAD. The purposes of this study are to definitize the diagnostic yield of 59 AAD patients, investigate the molecular pathological spectrum of AAD by NGS, and explore the future preclinical prospects of genetic diagnosis on AAD high-risk groups. We performed next-generation sequencing (NGS) based on screening of the 69 currently aortic dissections/aneurysms-associated genes on 59 sporadic AAD samples from South China. A Kaplan-Meier survival curve was constructed to compare the event-free survival depending on variant number. Overall, 67 variants were detected in 39 patients, among which 4 patients were identified with pathogenic variants and 13 patients were diagnosed with likely pathogenic variants. Seventeen genotype positive patients were identified in aggregate, and the diagnostic yield of our study is 28.8%. All genotype-positive variants were distributed in 11 genes, FBN1 variants were in the largest number among genotype-positive variants, which were detected for 4 times, ACTA2 for 3 times, ABCC6 and TGFBR1 twice, and NOS3, MYLK, XYLT1, TIMP4, TGFBR2, CNTN3, and PON1 once. Individuals with three or more variants showed shorter mean event-free survival than patients with fewer variants. Our observations broaden the genetic pathological spectrum of AAD. Furthermore, our research uncovered two susceptibility genes FBN1 and ACTA2 for Stanford type A AAD patients. Finally, our study concluded that the number of variants an individual harbored was an important consideration in risk stratification for individualized prediction and disease diagnosis.

[Molecular autopsy in sudden cardiac death]

Currently, there are a significant percentage of autopsies left without a conclusive diagnosis of death, especially when this lethal event occurs suddenly. Genetic analysis has been recently incorporated into the field of forensic medicine, especially in patients with sudden death and where no conclusive cause of death is identified after a complete medical-legal autopsy. Inherited arrhythmogenic diseases are the main cause of death in these cases. To date, more than 40 genes have been associated with arrhythmogenic disease, and causing sudden cardiac death has been described. The main arrhythmogenic diseases are Long QT Syndrome, Catecholaminergic Polymorphic Ventricular Tachycardia, Brugada Syndrome, and Short QT Syndrome. These post-mortem genetic studies, not only allow a diagnosis of the cause of death, but also allow a clinical translation in relatives, focusing on the early identification of individuals at risk of syncope, as well as adopting personalised therapeutic measures for the prevention of a lethal arrhythmic episode.