Interpretation of Incidental Genetic Findings Localizing to Genes Associated With Cardiac Channelopathies and Cardiomyopathies

Recent advances in next-genetic sequencing technology have facilitated an expansion in the use of exome and genome sequencing in the research and clinical settings. While this has aided in the genetic diagnosis of individuals with atypical clinical presentations, there has been a marked increase in the number of incidentally identified variants of uncertain diagnostic significance in genes identified as clinically actionable by the American College of Medical Genetics guidelines. Approximately 20 of these genes are associated with cardiac diseases, which carry a significant risk of sudden cardiac death. While identification of at-risk individuals is paramount, increased discovery of incidental variants of uncertain diagnostic significance has placed a burden on the clinician tasked with determining the diagnostic significance of these findings. Herein, we describe the scope of this emerging problem using cardiovascular genetics to illustrate the challenges associated with variants of uncertain diagnostic significance interpretation. We review the evidence for diagnostic weight of these variants, discuss the role of clinical genetics providers in patient care, and put forward general recommendations about the interpretation of incidentally identified variants found with clinical genetic testing.

Clinical Insights Into Heritable Cardiomyopathies

Cardiomyopathies (CMs) encompass a heterogeneous group of structural and functional abnormalities of the myocardium. The phenotypic characteristics of these myocardial diseases range from silent to symptomatic heart failure, to sudden cardiac death due to malignant tachycardias. These diseases represent a leading cause of cardiovascular morbidity, cardiac transplantation, and death. Since the discovery of the first locus associated with hypertrophic cardiomyopathy 30 years ago, multiple loci and molecular mechanisms have been associated with these cardiomyopathy phenotypes. Conversely, the disparity between the ever-growing landscape of cardiovascular genetics and the lack of awareness in this field noticeably demonstrates the necessity to update training curricula and educational pathways. This review summarizes the current understanding of heritable CMs, including the most common pathogenic gene variants associated with the morpho-functional types of cardiomyopathies: dilated, hypertrophic, arrhythmogenic, non-compaction, and restrictive. Increased understanding of the genetic/phenotypic associations of these heritable diseases would facilitate risk stratification to leveraging appropriate surveillance and management, and it would additionally provide identification of family members at risk of avoidable cardiovascular morbidity and mortality.

Special Issue “Cardiovascular Genetics”

Since the beginnings of cardiovascular genetics, it became evident in thousands of clinical cases that many cardiomyopathies, channelopathies, aortopathies as well as complex multifactorial diseases such as coronary artery disease, atherosclerosis or atrial fibrillation (AF) have a genetic etiology [...]

“The ultimate risk:” How clinicians assess the value and meaning of genetic data in cardiology

In modern medicine, health risks are often managed through the collection of health data and subsequent intervention. One of the goals of clinical genetics, for example, is to identify genetic predisposition to disease so that individuals can intervene to prevent potential harms. But recently, some clinicians have suggested that patients should undergo less testing and monitoring in an effort to reduce overdiagnosis and overtreatment. In this paper, I explore how clinicians navigate the tension between identifying real disease risks for their patients with concerns about overdiagnosis and overtreatment. I focus on clinicians ordering genetic testing for inherited cardiovascular diseases. Of the genes determined to be “clinically actionable” by the American College of Medical Genetics and Genomics (ACMG), half are related to cardiovascular diseases. But, due in part to high levels of uncertainty surrounding cardiovascular genetics, there is still disagreement within the field about how to order and interpret these tests. Based on semi-structured, in-depth interviews with 20 clinicians who order genetic testing for cardiovascular diseases, I find that there is considerable variability in the ways that clinicians determine which types of genetic tests are appropriate for their patients and how they interpret test results. Most importantly, I find that many providers do not presume that more genetic data will lead to better care. Instead, increased genetic data can lead to confusion and inappropriate treatment. This re-valuation of the utility of medical data is crucial for bioethicists to explore, especially as medical fields are sorting through increasing amounts of data.

Establishment of Specialized Clinical Cardiovascular Genetics Programs: Recognizing the Need and Meeting Standards: A Scientific Statement From the American Heart Association

Cardiovascular genetics is a rapidly evolving subspecialty within cardiovascular medicine, and its growth is attributed to advances in genome sequencing and genetic testing and the expanding understanding of the genetic basis of multiple cardiac conditions, including arrhythmias (channelopathies), heart failure (cardiomyopathies), lipid disorders, cardiac complications of neuromuscular conditions, and vascular disease, including aortopathies. There have also been great advances in clinical diagnostic methods, as well as in therapies to ameliorate symptoms, slow progression of disease, and mitigate the risk of adverse outcomes. Emerging challenges include interpretation of genetic test results and the evaluation, counseling, and management of genetically at-risk family members who have inherited pathogenic variants but do not yet manifest disease. With these advances and challenges, there is a need for specialized programs combining both cardiovascular medicine and genetics expertise. The integration of clinical cardiovascular findings, including those obtained from physical examination, imaging, and functional assessment, with genetic information allows for improved diagnosis, prognostication, and cascade family testing to identify and to manage risk, and in some cases to provide genotype-specific therapy. This emerging subspecialty may ultimately require a new cardiovascular subspecialist, the genetic cardiologist, equipped with these combined skills, to permit interpretation of genetic variation within the context of phenotype and to extend the utility of genetic testing. This scientific statement outlines current best practices for delivering cardiovascular genetic evaluation and care in both the pediatric and the adult settings, with a focus on team member expertise and conditions that most benefit from genetic evaluation.