Determining pathogenicity of genetic variants in hypertrophic cardiomyopathy: importance of periodic reassessment

Systematic reanalysis of copy number losses of uncertain clinical significance

BACKGROUND

Reanalysis of exome/genome data improves diagnostic yield. However, the value of reanalysis of clinical array comparative genomic hybridisation (aCGH) data has never been investigated. Case-by-case reanalysis can be challenging in busy diagnostic laboratories.

METHODS AND RESULTS

We harmonised historical postnatal clinical aCGH results from ~16 000 patients tested via our diagnostic laboratory over ~7 years with current clinical guidance. This led to identification of 37 009 copy number losses (CNLs) including 33 857 benign, 2173 of uncertain significance and 979 pathogenic. We found benign CNLs to be significantly less likely to encompass haploinsufficient genes compared with the pathogenic or CNLs of uncertain significance in our database. Based on this observation, we developed a reanalysis pipeline using up-to-date disease association data and haploinsufficiency scores and shortlisted 207 CNLs of uncertain significance encompassing at least one autosomal dominant disease-gene associated with haploinsufficiency or loss-of-function mechanism. Clinical scientist reviews led to reclassification of 15 CNLs of uncertain significance as pathogenic or likely pathogenic. This was ~0.7% of the starting cohort of 2173 CNLs of uncertain significance and 7.2% of 207 shortlisted CNLs. The reclassified CNLs included first cases of CNV-mediated disease for some genes where all previously described cases involved only point variants. Interestingly, some CNLs could not be reclassified because the phenotypes of patients with CNLs seemed distinct from the known clinical features resulting from point variants, thus raising questions about accepted underlying disease mechanisms.

CONCLUSIONS

Reanalysis of clinical aCGH data increases diagnostic yield.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Relationship Between Genotype Status and Clinical Outcome in Hypertrophic Cardiomyopathy

BACKGROUND

The genetic basis of hypertrophic cardiomyopathy (HCM) is complex, and the relationship between genotype status and clinical outcome is incompletely resolved.

METHODS AND RESULTS

We assessed a large international HCM cohort to define in contemporary terms natural history and clinical consequences of genotype. Consecutive patients (n=1468) with established HCM diagnosis underwent genetic testing. Patients with pathogenic (or likely pathogenic) variants were considered genotype positive (G+; n=312; 21%); those without definite disease-causing mutations (n=651; 44%) or variants of uncertain significance (n=505; 35%) were considered genotype negative (G-). Patients were followed up for a median of 7.8 years (interquartile range, 3.5-13.4 years); HCM end points were examined by cumulative event incidence. Over follow-up, 135 (9%) patients died, 33 from a variety of HCM-related causes. After adjusting for age, all-cause and HCM-related mortality did not differ between G- versus G+ patients (hazard ratio [HR], 0.78 [95% CI, 0.46-1.31]; P=0.37; HR, 0.93 [95% CI, 0.38-2.30]; P=0.87, respectively). Adverse event rates, including heart failure progression to class III/IV, heart transplant, or heart failure death, did not differ (G- versus G+) when adjusted for age (HR, 1.20 [95% CI, 0.63-2.26]; P=0.58), nor was genotype independently associated with sudden death event risk (HR, 1.39 [95% CI, 0.88-2.21]; P=0.16). In multivariable analysis, age was the only independent predictor of all-cause and HCM-related mortality, heart failure progression, and sudden death events.

CONCLUSIONS

In this large consecutive cohort of patients with HCM, genotype (G+ or G-) was not a predictor of clinical course, including all-cause and HCM-related mortality and risk for heart failure progression or sudden death. G+ status should not be used to dictate clinical management or predict outcome in HCM.

Identification of novel genetic variations in ABCB6 and GRN genes associated with HIV-associated lipodystrophy

Protease inhibitors (PIs) are associated with an incidence of lipodystrophy among people living with HIV(PLHIV). Lipodystrophiesare characterised by the loss of adipose tissue. Evidence suggests that a patient's lipodystrophy phenotype is influenced by genetic mutation, age, gender, and environmental and genetic factors, such as single-nucleotide variants (SNVs). Pathogenic variants are considered to cause a more significant loss of adipose tissue compared to non-pathogenic. Lipid metabolising enzymes and transporter genes have a role in regulating lipoprotein metabolism and have been associated with lipodystrophy in HIV-infected patients (LDHIV). The long-term effect of the lipodystrophy syndrome is related to cardiovascular diseases (CVDs). Hence, we determined the SNVs of lipid metabolising enzymes and transporter genes in a total of 48 patient samples, of which 24 were with and 24 were without HIV-associated lipodystrophy (HIVLD) using next-generation sequencing. A panel of lipid metabolism, transport and elimination genes were sequenced. Three novel heterozygous non-synonymous variants at exon 8 (c.C1400A:p.S467Y, c.G1385A:p.G462E, and c.T1339C:p.S447P) in the ABCB6 gene were identified in patients with lipodystrophy. One homozygous non-synonymous SNV (exon5:c.T358C:p.S120P) in the GRN gene was identified in patients with lipodystrophy. One novelstop-gain SNV (exon5:c.C373T:p.Q125X) was found in the GRN gene among patients without lipodystrophy. Patients without lipodystrophy had one homozygous non-synonymous SNV (exon9:c.G1462T:p.G488C) in the ABCB6 gene. Our findings suggest that novel heterozygous non-synonymous variants in the ABCB6 gene may contribute to defective protein production, potentially intensifying the severity of lipodystrophy. Additionally, identifying a stop-gain SNV in the GRN gene among patients without lipodystrophy implies a potential role in the development of HIVLD.

Underrepresentation of Diverse Ancestries Drives Uncertainty in Genetic Variants Found in Cardiomyopathy-Associated Genes

BACKGROUND

Thousands of genetic variants have been identified in cardiomyopathy-associated genes. Diagnostic genetic testing is key for evaluation of individuals with suspected cardiomyopathy. While accurate variant pathogenicity assignment is important for diagnosis, the frequency of and factors associated with clinically relevant assessment changes are unclear.

OBJECTIVES

The authors aimed to characterize pathogenicity assignment change in cardiomyopathy-associated genes and to identify factors associated with this change.

METHODS

We identified 10 sarcomeric and 6 desmosomal genetic cardiomyopathy-associated genes along with comparison gene sets. We analyzed clinically meaningful changes in pathogenicity assignment between any of the following: pathogenic/likely pathogenic (P/LP), conflicting interpretations of pathogenicity or variant of unknown significance (C/VUS), and benign/likely benign. We explored association of minor allele frequency (MAF) differences between well, and traditionally poorly, represented ancestries in genetic studies with assessment stability. Analyses were performed using ClinVar and GnomAD data.

RESULTS

Of the 30,975 cardiomyopathy-associated gene variants in ClinVar, 2,276 of them (7.3%) had a clinically meaningful change in pathogenicity assignment over the study period, 2011 to 2021. Sixty-seven percent of variants that underwent a clinically significant change moved from P/LP or benign/likely benign to C/VUS. Among cardiomyopathy variants downgraded from P/LP, 35% had a MAF above 1 × 10 -4 in non-Europeans and below 1 × 10 -4 in Europeans.

CONCLUSIONS

Over the past 10 years, 7.3% of cardiomyopathy gene variants underwent a clinically meaningful change in pathogenicity assignment. Over 30% of downgrades from P/LP may be attributable to higher MAF in Non-Europeans than Europeans. This finding suggests that low ancestral diversity in genetic studies has increased diagnostic uncertainty in cardiomyopathy gene variants.

Principles of Genetic Counseling in Inherited Heart Conditions

Cardiac genetic counseling is the process of helping individuals adapt to a personal diagnosis or family history of an inherited heart condition. The process is shown to benefit patients and includes specialized skills, such as counseling children and interpreting complex genetic results. Emerging areas include: evolving service delivery models for caring for patients and communicating risk to relatives, new areas of need including postmortem molecular autopsy, and new populations of individuals found to carry a likely pathogenic/pathogenic cardiac variant identified through genomic screening. This article provides an overview of the cardiac genetic counseling process and evolving areas in the field.

Evolution of genetic testing and gene therapy in hypertrophic cardiomyopathy

Studies over the last 30 years have identified hypertrophic cardiomyopathy (HCM) as predominantly an autosomal dominant disorder caused by disease-causing variants in genes encoding the sarcomere proteins critical for contractile function. The two most common disease genes implicated are the MYBPC3 and MYH7 genes, with disease-causing variants in these two genes accounting for 70-80% of all genotype-positive HCM patients. This increased knowledge of the genetic basis of HCM has heralded the era of precision medicine, with genetic testing leading to more improved and precise diagnosis, effective cascade genetic testing in at-risk family members, assistance with reproductive decisions, targeted therapeutics guided by both phenotype and genotype, and providing important insights into risk stratification and prognosis. Most recently, novel insights into genetic mechanisms have been elucidated, spanning non-Mendelian aetiologies, non-familial forms of HCM, and development of polygenic risk scores. These advances have laid the platform for exciting future endeavours such as newer gene therapy approaches in HCM, including gene replacement studies and genome editing approaches to ultimately cure disease. This brief review summarises the current role of genetic testing in HCM patients and families, and introduces some new mechanistic insights leading to the consideration of gene therapy approaches for HCM.

From diagnostic testing to precision medicine: the evolving role of genomics in cardiac channelopathies and cardiomyopathies in children

Pediatric sudden cardiac death (SCD) is the sudden unexpected death of a child or adolescent due to a presumed cardiac etiology. Heritable causes of pediatric SCD are predominantly cardiomyopathies and cardiac ion channelopathies. This review illustrates recent advances in determining the genetic cause of established and emerging channelopathies and cardiomyopathies, and how broader genomic sequencing is uncovering complex interactions between genetic architecture and disease manifestation. We discuss innovative models and experimental platforms for resolving the variant of uncertain significance as both the variants and genes associated with disease continue to evolve. Finally, we highlight the growing problem of incidentally identified variants in cardiovascular disease-causing genes and review innovative methods to determining whether these variants may ultimately result in penetrant disease. Overall, we seek to illustrate both the promise and inherent challenges in bridging the traditional role for genetics in diagnosing cardiomyopathies and channelopathies to one of true risk-predictive precision medicine.

Pathogenicity Assignment of Variants in Genes Associated With Cardiac Channelopathies Evolve Toward Diagnostic Uncertainty

BACKGROUND

Accurately determining variant pathogenicity is critical in the diagnosis of cardiac channelopathies; however, it remains unknown how variant pathogenicity status changes over time. Our aim is to use a comprehensive analysis of ClinVar to understand the mutability of variant evaluation in channelopathy-associated genes to inform clinical decision-making around variant calling.

METHODS

We identified 10 genes (RYR2, CASQ2, KCNQ1, KCNH2, SCN5A, CACNA1C, CALM1, CALM2, CALM3, TRDN) strongly associated with cardiac channelopathies, as well as 3 comparison gene sets (disputed long QT syndrome, sudden unexpected death in epilepsy, and all ClinVar). We comprehensively analyzed variant pathogenicity calls over time using the ClinVar database with Rstudio. Analyses focused on the frequency and directionality of clinically meaningful changes in disease association, defined as a change from one of the following three categories to another: likely benign/benign, conflicting evidence of pathogenicity/variant of uncertain significance, and likely pathogenic/pathogenic.

RESULTS

In total, among channelopathy-associated genes, there were 9975 variants in ClinVar and 8.4% had a clinically meaningful change in disease association at least once over the past 10 years, as opposed to 4.9% of all ClinVar variants. The 3 channelopathy-associated genes with the most variants undergoing a clinically significant change were KCNQ1 (20.9%), SCN5A (11.2%), and KCNH2 (10.1%). Ten of the 12 included genes had variant evaluations that trended toward diagnostic uncertainty over time. Specifically, channelopathy-associated gene variants with either pathogenic/likely pathogenic or benign/likely benign assignments were 5.6× and 2×, respectively, as likely to be reevaluated to conflicting/variant of uncertain significance compared to the converse.

CONCLUSIONS

Over the past 10 years, 8.4% of variants in channelopathy-associated genes have changed pathogenicity status with a decline in overall diagnostic certainty. Ongoing clinical and genetic variant follow-up is needed to account for presence of clinically meaningful change in variant pathogenicity assignment over time.

Validation of New Gene Variant Classification Methods: a Field-Test in Diagnostic Cardiogenetics

Background: In the molecular genetic diagnostics of Mendelian disorders, solutions are needed for the major challenge of dealing with the large number of variants of uncertain significance (VUSs) identified using next-generation sequencing (NGS). Recently, promising approaches using constraint metrics to calculate case excess scores (CE), etiological fractions (EF), and gnomAD-derived constraint scores have been reported that estimate the likelihood of rare variants in specific genes or regions that are pathogenic. Our objective is to study the usability of these constraint data into variant interpretation in a diagnostic setting, using our cardiomyopathy cohort.

Methods and Results: Patients (N = 2002) referred for clinical genetic diagnostics underwent NGS testing of 55–61 genes associated with cardiomyopathies. Previously classified likely pathogenic (LP) and pathogenic (P) variants were used to validate the use of data from CE, EF, and gnomAD constraint analyses for (re)classification of associated variant types in specific cardiomyopathy subtype-related genes. The classifications corroborated in 94% (354/378) of cases. Next, we reclassified 23 unique VUSs to LP, increasing the diagnostic yield by 1.2%. In addition, 106 unique VUSs (5.3% of patients) were prioritized for co-segregation or functional analyses.

Conclusions: Our analysis confirms that the use of constraint metrics data can improve variant interpretation, and we, therefore, recommend using constraint scores on other cohorts and disorders and its inclusion in variant interpretation protocols.

It Is Not Carved in Stone—The Need for a Genetic Reevaluation of Variants in Pediatric Cardiomyopathies

(1) Background: In cardiomyopathies, identification of genetic variants is important for the correct diagnosis and impacts family cascade screening. A classification system was published by the American College of Medical Genetics and Genomics (ACMG) in 2015 to standardize variants’ classification. The aim of the study was to determine the rate of reclassification of previously identified variants in patients with childhood-onset cardiomyopathies. (2) Methods: Medical records of patients and their relatives were screened for clinical and genetic information at the Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich. Patients without an identified genetic variant were excluded from further analyses. Previously reported variants were reevaluated by the ACMG criteria in November 2021. (3) Results: Data from 167 patients or relatives of patients with childhood-onset cardiomyopathy from 137 families were analyzed. In total, 45 different genetic variants were identified in 71 individuals. Classification changed in 29% (13/45) with the greatest shift in “variants of unknown significance” to “(likely) benign” (9/13). (4) Conclusions: In patients with childhood-onset cardiomyopathies, nearly a third of reported genetic variants change mostly to more benign classes upon reclassification. Given the impact on patient management and cascade screening, this finding underlines the importance of continuous genetic counseling and variant.

Novel Mutations in β-MYH7 Gene in Indian Patients With Dilated Cardiomyopathy

Background

Methods

Results

Conclusions

Whole-exome sequencing reveals MYH7 p.R671C mutation in three different phenotypes of familial hypertrophic cardiomyopathy

Familial hypertrophic cardiomyopathy (HCM) is one of the most common types of genetic heart disorder and features high genetic heterogeneity. HCM is a major cause of sudden cardiac death and also an important cause of heart failure-related disability. A pedigree with suspected familial HCM was recruited for the present study to identify genetic abnormalities. HCM was confirmed by echocardiography and clinical data of the family members were collected. Genomic DNA was extracted from the peripheral blood and sequenced based on standard whole-exome sequencing (WES) protocols. Sanger sequencing was further performed to verify mutation sites and their association with HCM. WES and Sanger sequencing revealed a heterozygous missense mutation (c.2011C>T p.R671C) in myosin heavy chain 7 (MYH7) that was identified in three family members. The Arg671Cys mutation was located in exon 18 and, to the best of our knowledge, has not been previously reported in familial HCM. Furthermore, family members carrying the same mutated gene were of different sexes and clinical phenotypes. They included the proband, a 17-year-old survivor of sudden cardiac arrest with ventricular systolic dysfunction, the proband's maternal uncle, who presented with ventricular diastolic dysfunction and the proband's mother, who had no obvious clinical symptoms and did not present with cardiac dysfunction. However, echocardiology indicated that the proband's mother had an enlarged left atrium, slightly thicker right anterior wall and anterior septum and an expanded atrial septum. Therefore, HCM exhibited obvious genetic and phenotypic heterogeneity. To the best of our knowledge, the present study was the first to report such a mutation in the MYH7 gene in familial HCM. In addition, the present study demonstrated that WES is a powerful tool for identifying genetic variants in HCM.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

Clinical and laboratory reporting impact of ACMG-AMP and modified ClinGen variant classification frameworks in MYH7-related cardiomyopathy

PURPOSE

ClinGen provides gene-specific guidance for interpretation of sequence variants in MYH7. We assessed laboratory and clinical impact of reclassification by the American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) and ClinGen recommendations in 43 MYH7 variants reported by a diagnostic laboratory between 2013 and 2017.

METHODS

Fifty-two proband reports containing MYH7 variants were reinterpreted by original ACMG-AMP and ClinGen guidelines. Evidence items were compared across schemes and reasons for classification differences recorded. Laboratory impact was assessed by number of recommended report reissues, and reclassifications coded as clinically "actionable" or "equivalent." Available pedigrees were reviewed to describe projected cascade impact.

RESULTS

ClinGen produced a higher proportion of diagnostic classifications (65% of variants) compared with ACMG-AMP (54%) and fewer variants of uncertain significance (30% versus 42%). ClinGen classification resulted in actionable changes in 18% of variants with equal upgrades and downgrades from original report. ClinGen's revisions to PM1 and PS4 contributed to classification differences in 21% and 19% of variants respectively. Each classification change per proband report impacted, on average, 3.1 cascade reports with a further 6.3 first- and second-degree relatives potentially available for genotyping per family.

CONCLUSION

ClinGen's gene-specific criteria provide expert-informed guidance for interpretation of MYH7 sequence variants. Periodic re-evaluation improves diagnostic confidence and should be considered by clinical and laboratory teams.

Rare Variants Associated with Arrhythmogenic Cardiomyopathy: Reclassification Five Years Later

Genetic interpretation of rare variants associated with arrhythmogenic cardiomyopathy (ACM) is essential due to their diagnostic implications. New data may relabel previous variant classifications, but how often reanalysis is necessary remains undefined. Five years ago, 39 rare ACM-related variants were identified in patients with features of cardiomyopathy. These variants were classified following the American College of Medical Genetics and Genomics’ guidelines. In the present study, we reevaluated these rare variants including novel available data. All cases carried one rare variant classified as being of ambiguous significance (82.05%) or likely pathogenic (17.95%) in 2016. In our comprehensive reanalysis, the classification of 30.77% of these variants changed, mainly due to updated global frequencies. As in 2016, nowadays most variants were classified as having an uncertain role (64.1%), but the proportion of variants with an uncertain role was significantly decreased (17.95%). The percentage of rare variants classified as potentially deleterious increased from 17.95% to 23.07%. Moreover, 83.33% of reclassified variants gained certainty. We propose that periodic genetic reanalysis of all rare variants associated with arrhythmogenic cardiomyopathy should be undertaken at least once every five years. Defining the roles of rare variants may help clinicians obtain a definite diagnosis.

Investigation of current models of care for genetic heart disease in Australia: A national clinical audit

BACKGROUND

This sub-study of the Australian Genomics Cardiovascular Genetic Disorders Flagship sought to conduct the first nation-wide audit in Australia to establish the current practices across cardiac genetics clinics.

METHOD

An audit of records of patients with a suspected genetic heart disease (cardiomyopathy, primary arrhythmia, autosomal dominant congenital heart disease) who had a cardiac genetics consultation between 1st January 2016 and 31 July 2018 and were offered a diagnostic genetic test.

RESULTS

This audit included 536 records at multidisciplinary cardiac genetics clinics from 11 public tertiary hospitals across five Australian states. Most genetic consultations occurred in a clinic setting (90%), followed by inpatient (6%) and Telehealth (4%). Queensland had the highest proportion of Telehealth consultations (9% of state total). Sixty-six percent of patients had a clinical diagnosis of a cardiomyopathy, 28% a primary arrhythmia, and 0.7% congenital heart disease. The reason for diagnosis was most commonly as a result of investigations of symptoms (73%). Most patients were referred by a cardiologist (85%), followed by a general practitioner (9%) and most genetic tests were funded by the state Genetic Health Service (73%). Nationally, 29% of genetic tests identified a pathogenic or likely pathogenic gene variant; 32% of cardiomyopathies, 26% of primary arrhythmia syndromes, and 25% of congenital heart disease.

CONCLUSION

We provide important information describing the current models of care for genetic heart diseases throughout Australia. These baseline data will inform the implementation and impact of whole genome sequencing in the Australian healthcare landscape.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases.

STRUCTURE

Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Hereditary Hypertrophic Cardiomyopathy in Children and Young Adults-The Value of Reevaluating and Expanding Gene Panel Analyses

Introduction: Sudden cardiac death (SCD) and early onset cardiomyopathy (CM) in the young will always lead to suspicion of an underlying genetic disorder. Incited by the rapid advances in genetic testing for disease we have revisited families, which previously tested “gene-negative” for familial predominantly pediatric CM, in hopes of finding a causative gene variant. Methods: 10 different families with non-syndromic pediatric CM or hypertrophic cardiomyopathy (HCM) with severe disease progression and/or heredity for HCM/CM related SCD with “gene-negative” results were included. The index patient underwent genetic testing with a recently updated gene panel for CM and SCD. In case of failure to detect a pathogenic variant in a relevant gene, the index patient and both parents underwent clinical (i.e., partial) exome sequencing (trio-exome) in order to catch pathogenic variants linked to the disease in genes that were not included in the CM panel. Results: The mean age at clinical presentation of the 10 index cases was 12.5 years (boys 13.4 years, n = 8; girls 9 years, n = 2) and the family history burden was 33 HCM/CM cases including 9 HCM-related SCD and one heart transplantation. In 5 (50%) families we identified a genetic variant classified as pathogenic or likely pathogenic, in accordance with the American College of Medical Genetics and Genomics (ACMG) criteria, in MYH7 (n = 2), RBM20, ALPK3, and PGM1, respectively, and genetic variants of unknown significance (VUS) segregating with the disease in an additional 3 (30%) families, in MYBPC3, ABCC9, and FLNC, respectively. Conclusion: Our results show the importance of renewed thorough clinical assessment and the necessity to challenge previous genetic test results with more comprehensive updated gene panels or exome sequencing if the initial test failed to identify a causative gene for early onset CM or SCD in children. In pediatric cardiomyopathy cases when the gene panel still fails to detect a causative variant, a trio exome sequencing strategy might resolve some unexplained cases, especially if a multisystemic condition is clinically missed.

Panorama of the distal myopathies

Distal myopathies are genetic primary muscle disorders with a prominent weakness at onset in hands and/or feet. The age of onset (from early childhood to adulthood), the distribution of muscle weakness (upper versus lower limbs) and the histological findings (ranging from nonspecific myopathic changes to myofibrillar disarrays and rimmed vacuoles) are extremely variable. However, despite being characterized by a wide clinical and genetic heterogeneity, the distal myopathies are a category of muscular dystrophies: genetic diseases with progressive loss of muscle fibers. Myopathic congenital arthrogryposis is also a form of distal myopathy usually caused by focal amyoplasia. Massive parallel sequencing has further expanded the long list of genes associated with a distal myopathy, and contributed identifying as distal myopathy-causative rare variants in genes more often related with other skeletal or cardiac muscle diseases. Currently, almost 20 genes (ACTN2, CAV3, CRYAB, DNAJB6, DNM2, FLNC, HNRNPA1, HSPB8, KHLH9, LDB3, MATR3, MB, MYOT, PLIN4, TIA1, VCP, NOTCH2NLC, LRP12, GIPS1) have been associated with an autosomal dominant form of distal myopathy. Pathogenic changes in four genes (ADSSL, ANO5, DYSF, GNE) cause an autosomal recessive form; and disease-causing variants in five genes (DES, MYH7, NEB, RYR1 and TTN) result either in a dominant or in a recessive distal myopathy. Finally, a digenic mechanism, underlying a Welander-like form of distal myopathy, has been recently elucidated. Rare pathogenic mutations in SQSTM1, previously identified with a bone disease (Paget disease), unexpectedly cause a distal myopathy when combined with a common polymorphism in TIA1. The present review aims at describing the genetic basis of distal myopathy and at summarizing the clinical features of the different forms described so far.

Impact of Genetic Variant Reassessment on the Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy Based on the 2010 Task Force Criteria

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy, which is associated with life-threatening ventricular arrhythmias. Approximately 60% of patients carry a putative disease-causing genetic variant, but interpretation of genetic test results can be challenging. The aims of this study were to systematically reclassify genetic variants in patients with ARVC and to assess the impact on ARVC diagnosis.

METHODS

This study included patients from the Multicenter Zurich ARVC Registry who hosted a genetic variant deemed to be associated with the disease. Reclassification of pathogenicity was performed according to the modified 2015 American College of Medical Genetics criteria. ARVC diagnosis (categories: definite, borderline, possible) based on the 2010 Task Force Criteria was reclassified after genetic readjudication.

RESULTS

In 79 patients bearing 80 unique genetic variants, n=47 (58.8%) genetic variants were reclassified, and reclassification was judged to be clinically relevant in n=33 (41.3%). Variants in plakophilin-2 (PKP2) were shown to reclassify less frequently as compared with other genes (PKP2, n=1, 8.3%; desmosomal non-PKP2, n=20, 66.7%; nondesmosomal, n=26, 68.4%; P=0.001for overall comparison; PKP2 versus desmosomal non-PKP2, P=0.001; PKP2 versus nondesmosomal, P<0.001). Genetic reclassification impacted ARVC diagnosis. Eight patients (10.1%) were downgraded from definite to borderline/possible disease at the time of initial genetic testing as well as last follow-up, respectively. Separate genetic reclassification in family members led to downgrading of n=5 (38.5%) variants.

CONCLUSIONS

Given that approximately half of genetic variants were reclassified, with 10.1% of patients losing their definite disease status, accurate determination of variant pathogenicity is of utmost importance in the diagnosis of ARVC.

The p.(Cys150Tyr) variant in CSRP3 is associated with late-onset hypertrophic cardiomyopathy in heterozygous individuals

INTRODUCTION AND OBJECTIVES

Up to 50% of patients with hypertrophic cardiomyopathy (HCM) show no disease-causing variants in genetic studies. Mutations in CSRP3 have been associated with HCM, but evidence supporting pathogenicity is inconclusive. In this study, we describe an HCM cohort with a missense variant in CSRP3 (p.Cys150Tyr) with supporting evidence for pathogenicity and a description of the associated phenotype.

METHODS

CSRP3 was sequenced in 6456 index cases with a diagnosis of HCM and in 5012 probands with other cardiomyopathies. In addition, 3372 index cases with hereditary cardiovascular disorders other than cardiomyopathies (mainly channelopathies and aortopathies) were used as controls.

RESULTS

The p.(Cys150Tyr) variant was identified in 11 unrelated individuals of the 6456 HCM probands, and it was not identified in patients with other cardiomyopathies (p < 0.0001) or in our control population (p < 0.0001). Ten of the index cases were heterozygous and one was homozygous. Homozygous had a more severe phenotype. Family screening identified 17 other carriers. Wild-type individuals showed no signs of disease. The mean age at diagnosis of affected individuals was 55 ± 13 years, and the mean left ventricular wall thickness was 18 ± 3 mm. The variant showed highly age-dependent penetrance. After a mean follow-up of 11 (±8) years, no adverse events were reported in any of the HCM patients.

CONCLUSIONS

The p.(Cys150Tyr) variant in CSRP3 causes late-onset and low risk form of hypertrophic cardiomyopathy in heterozygous carriers.

Genetic Testing for Inherited Cardiovascular Diseases: A Scientific Statement From the American Heart Association

Advances in human genetics are improving the understanding of a variety of inherited cardiovascular diseases, including cardiomyopathies, arrhythmic disorders, vascular disorders, and lipid disorders such as familial hypercholesterolemia. However, not all cardiovascular practitioners are fully aware of the utility and potential pitfalls of incorporating genetic test results into the care of patients and their families. This statement summarizes current best practices with respect to genetic testing and its implications for the management of inherited cardiovascular diseases.

Mind the gap: Knowledge deficits in evaluating young sudden cardiac death

Sudden cardiac arrest affects around half a million people aged under 50 years old annually, with a 90% mortality rate. Despite high patient numbers and clear clinical need to improve outcomes, many gaps exist in the evidence underpinning patients' management. Domains identifying the greatest barriers to conducting trials are the prehospital and forensic settings, which also provide care to the majority of patients. Addressing gaps in evidence along each point of the cardiac arrest trajectory is a key clinical priority.

A Person-Centered Approach to Cardiovascular Genetic Testing

Cardiovascular genetic counselors provide guidance to people facing the reality or prospect of inherited cardiovascular conditions. Key activities in this role include discussing clinical cardiac screening for at-risk family members and offering genetic testing. Psychological factors often influence whether patients choose to have genetic testing and how they understand and communicate the results to at-risk relatives, so psychological counseling increases the impact of genetic education and medical recommendations. This work reviews the literature on the factors that influence patient decisions about cardiovascular genetic testing and the psychological impact of results on people who opt to test. It also models use of a psychological framework to apply themes from the literature to routine cardiovascular genetic counseling practice. Modifications of the framework are provided to show how it can be adapted to serve the needs of both new and experienced genetic counselors.

Protein Thermodynamic Destabilization in the Assessment of Pathogenicity of a Variant of Uncertain Significance in Cardiac Myosin Binding Protein C

In the era of next generation sequencing (NGS), genetic testing for inherited disorders identifies an ever-increasing number of variants whose pathogenicity remains unclear. These variants of uncertain significance (VUS) limit the reach of genetic testing in clinical practice. The VUS for hypertrophic cardiomyopathy (HCM), the most common familial heart disease, constitute over 60% of entries for missense variants shown in ClinVar database. We have studied a novel VUS (c.1809T>G-p.I603M) in the most frequently mutated gene in HCM, MYBPC3, which codes for cardiac myosin-binding protein C (cMyBPC). Our determinations of pathogenicity integrate bioinformatics evaluation and functional studies of RNA splicing and protein thermodynamic stability. In silico prediction and mRNA analysis indicated no alteration of RNA splicing induced by the variant. At the protein level, the p.I603M mutation maps to the C4 domain of cMyBPC. Although the mutation does not perturb much the overall structure of the C4 domain, the stability of C4 I603M is severely compromised as detected by circular dichroism and differential scanning calorimetry experiments. Taking into account the highly destabilizing effect of the mutation in the structure of C4, we propose reclassification of variant p.I603M as likely pathogenic. Looking into the future, the workflow described here can be used to refine the assignment of pathogenicity of variants of uncertain significance in MYBPC3.

Potential digenic inheritance of familial hypertrophic cardiomyopathy identified by whole-exome sequencing

BACKGROUND

The aim of this study was to identify the genetic causes of patients with hypertrophic cardiomyopathy (HCM) within a family. Most of the previous studies found point mutations as the genetic causes for HCM, whole-gene deletion was rarely reported.

METHODS

Although, clinical genetic testing has been widely used for identifying variants in HCM patients, structural variations are understudied, partly owing to the inadequacy of the available methodology. In the present study, whole-exome sequencing (WES) and Sanger sequencing validation was used to identify the genetic causes in patients with familial HCM.

RESULTS

A genomic deletion in Chromosome 19 containing the whole of troponin I3 gene (TNNI3), and the p.Ile736Thr variant in the myosin heavy chain 7 gene (MYH7) were identified in two patients with familial HCM by WES. The p.Ile736Thr variant is further validated by Sanger sequencing and is predicted as a pathogenic variant by in silico analysis.

CONCLUSION

We added the notion that not only p.Ile736Thr variant of MYH7, but also TNNI3 deletion might potentially contribute to HCM pathogenesis. Our study also suggested WES was a powerful tool to identify the genetic variants causing HCM.

Genetic susceptibility in pharmacodynamic and pharmacokinetic pathways underlying drug-induced arrhythmia and sudden unexplained deaths

Drug-induced arrhythmia is an adverse drug reaction that can be potentially fatal since it is mostly related to drug-induced QT prolongation, a known risk factor for Torsade de Pointes and sudden cardiac death (SCD). Several risk factors have been described in association to these drug-induced events, such as preexistent cardiac disease and genetic variation. Our objective was to study the genetic susceptibility in pharmacodynamic and pharmacokinetic pathways underlying suspected drug-induced arrhythmias and sudden unexplained deaths in 32 patients. The genetic component in the pharmacodynamic pathway was studied by analysing 96 genes associated with higher risk of SCD through massive parallel sequencing. Pharmacokinetic-mediated genetic susceptibility was investigated by studying the genes encoding cytochrome P450 enzymes using medium-throughput genotyping. Pharmacodynamic analysis showed three probably pathogenic variants and 45 variants of uncertain significance in 28 patients, several of them previously described in relation to mild or late onset cardiomyopathies. These results suggest that genetic variants in cardiomyopathy genes, in addition to those related with channelopathies, could be relevant to drug-induced cardiotoxicity and contribute to the arrhythmogenic phenotype. Pharmacokinetic analysis showed three patients that could have an altered metabolism of the drugs they received involving CYP2C19 and/or CYP2D6, probably contributing to the arrhythmogenic phenotype. The study of genetic variants in both pharmacodynamic and pharmacokinetic pathways may be a useful strategy to understand the multifactorial mechanism of drug-induced events in both clinical practice and forensic field. However, it is necessary to comprehensively study and evaluate the contribution of the genetic susceptibility to drug-induced cardiotoxicity.

Perceptions of genetic variant reclassification in patients with inherited cardiac disease

Interpretation of sequence variants is an ongoing challenge and new approaches aim to increase stringency. The reclassification of variants has the potential to alter medical management and elicit psychosocial consequences for patients. The perspective of patients with an inherited cardiac disease and a clinically significant variant reclassification was explored through semi-structured phone interviews. Participants were recruited from two specialized multidisciplinary centers in Canada and Australia. Qualitative analysis was performed through a thematic analysis approach. Fifteen participants were interviewed, including 9 (60%) with an inherited cardiomyopathy and 6 (40%) with an inherited arrhythmia syndrome. Six (40%) patients had a classification upgrade, while 9 (60%) had a downgrade. Four major themes emerged: (1) reactions towards the reclassified variant; (2) impact on decision-making; (3) perception of the reclassification process; and (4) improvement of the reclassification process. Many patients adjusted to the reclassification, however some misunderstood the implications, impacting their responses and decision-making. In conclusion, careful discussion with patients about uncertainty and the potential for reclassification are crucial to ensure a deeper understanding of the outcome of genetic testing and impact on families.

Biallelic mutation in MYH7 and MYBPC3 leads to severe cardiomyopathy with left ventricular noncompaction phenotype

Dominant mutations in the MYH7 and MYBPC3 genes are common causes of inherited cardiomyopathies, which often demonstrate variable phenotypic expression and incomplete penetrance across family members. Biallelic inheritance is rare but allows gaining insights into the genetic mode of action of single variants. Here, we present three cases carrying a loss-of-function (LoF) variant in a compound heterozygous state with a missense variant in either MYH7 or MYBPC3 leading to severe cardiomyopathy with left ventricular noncompaction. Most likely, MYH7 haploinsufficiency due to one LoF allele results in a clinical phenotype only in compound heterozygous form with a missense variant. In contrast, haploinsufficiency in MYBPC3 results in a severe early-onset ventricular noncompaction phenotype requiring heart transplantation when combined with a de novo missense variant on the second allele. In addition, the missense variant may lead to an unstable protein, as overall only 20% of the MYBPC3 protein remain detectable in affected cardiac tissue compared to control tissue. In conclusion, in patients with early disease onset and atypical clinical course, biallelic inheritance or more complex variants including copy number variations and de novo mutations should be considered. In addition, the pathogenic consequence of variants may differ in heterozygous versus compound heterozygous state.

Evaluating the Clinical Validity of Hypertrophic Cardiomyopathy Genes

BACKGROUND

Genetic testing for families with hypertrophic cardiomyopathy (HCM) provides a significant opportunity to improve care. Recent trends to increase gene panel sizes often mean variants in genes with questionable association are reported to patients. Classification of HCM genes and variants is critical, as misclassification can lead to genetic misdiagnosis. We show the validity of previously reported HCM genes using an established method for evaluating gene-disease associations.

METHODS

A systematic approach was used to assess the validity of reported gene-disease associations, including associations with isolated HCM and syndromes including left ventricular hypertrophy. Genes were categorized as having definitive, strong, moderate, limited, or no evidence of disease causation. We also reviewed current variant classifications for HCM in ClinVar, a publicly available variant resource.

RESULTS

Fifty-seven genes were selected for curation based on their frequent inclusion in HCM testing and prior association reports. Of 33 HCM genes, only 8 (24%) were categorized as definitive ( MYBPC3, MYH7, TNNT2, TNNI3, TPM1, ACTC1, MYL2, and MYL3); 3 had moderate evidence ( CSRP3, TNNC1, and JPH2; 33%); and 22 (66%) had limited (n=16) or no evidence (n=6). There were 12 of 24 syndromic genes definitively associated with isolated left ventricular hypertrophy. Of 4191 HCM variants in ClinVar, 31% were in genes with limited or no evidence of disease association.

CONCLUSIONS

The majority of genes previously reported as causative of HCM and commonly included in diagnostic tests have limited or no evidence of disease association. Systematically curated HCM genes are essential to guide appropriate reporting of variants and ensure the best possible outcomes for HCM families.

Genetic Testing and Counseling for Hypertrophic Cardiomyopathy

Genetic testing has become more accessible and is increasingly being incorporated into the care of patients with hypertrophic cardiomyopathy. Genetic test results can help to refine diagnosis and distinguish at-risk relatives from those who are not at risk.

Application of Single-Nucleotide Polymorphism-Related Risk Estimates in Identification of Increased Genetic Susceptibility to Cardiovascular Diseases: A Literature Review

Background

Although largely preventable, cardiovascular diseases (CVDs) are the biggest cause of death worldwide. Common complex cardiovascular disorders (e.g., coronary heart disease, hypertonia, or thrombophilia) result from a combination of genetic alterations and environmental factors. Recent advances in the genomics of CVDs have fostered huge expectations about future use of susceptibility variants for prevention, diagnosis, and treatment. Our aim was to summarize the latest developments in the field from a public health perspective focusing on the applicability of data on single-nucleotide polymorphisms (SNPs), through a systematic review of studies from the last decade on genetic risk estimating for common CVDs.

Methods

Several keywords were used for searching the PubMed, Embase, CINAHL, and Web of Science databases. Recent advances were summarized and structured according to the main public health domains (prevention, early detection, and treatment) using a framework suggested recently for translational research. This framework includes four recommended phases: “T1. From gene discovery to candidate health applications; T2. From health application to evidence-based practice guidelines; T3. From evidence-based practice guidelines to health practice; and T4. From practice to population health impacts.”

Results

The majority of translation research belongs to the T1 phase “translation of basic genetic/genomic research into health application”; there are only a few population-based impacts estimated. The studies suggest that an SNP is a poor estimator of individual risk, whereas an individual’s genetic profile combined with non-genetic risk factors may better predict CVD risk among certain patient subgroups. Further research is needed to validate whether these genomic profiles can prospectively identify individuals at risk to develop CVDs. Several research gaps were identified: little information is available on studies suggesting “Health application to evidence-based practice guidelines”; no study is available on “Guidelines to health practice.” It was not possible to identify studies that incorporate environmental or lifestyle factors in the risk estimation.

Conclusion

Currently, identifying populations having a larger risk of developing common CVDs may result in personalized prevention programs by reducing people’s risk of onset or disease progression. However, limited evidence is available on the application of genomic results in health and public health practice.

Clinically impactful differences in variant interpretation between clinicians and testing laboratories: a single-center experience

PurposeTo describe the frequency and nature of differences in variant classifications between clinicians and genetic testing laboratories.MethodsRetrospective review of variants identified through genetic testing ordered in routine clinical care by clinicians in the Stanford Center for Inherited Cardiovascular Disease. We compared classifications made by clinicians, the testing laboratory, and other laboratories in ClinVar.ResultsOf 688 laboratory classifications, 124 (18%) differed from the clinicians' classifications. Most differences in classification would probably affect clinical care of the patient and/or family (83%, 103/124). The frequency of discordant classifications differed depending on the testing laboratory (P < 0.0001) and the testing laboratory's classification (P < 0.00001). For the majority (82/124, 66%) of discordant classifications, clinicians were more conservative (less likely to classify a variant pathogenic or likely pathogenic). The clinicians' classification was discordant with one or more submitter in ClinVar in 49.1% (28/57) of cases, while the testing laboratory's classification was discordant with a ClinVar submitter in 82.5% of cases (47/57, P = 0.0002).ConclusionThe clinical team disagreed with the laboratory's classification at a rate similar to that of reported disagreements between laboratories. Most of this discordance was clinically significant, with clinicians tending to be more conservative than laboratories in their classifications.

Communication of genetic information to families with inherited rhythm disorders

Given the dynamic nature of the electrical activity of the heart and ongoing challenges in the diagnostics of inherited heart rhythm disorders, genetic information can be a vital aspect of family management. Communication of genetic information is complex, and the responsibility to convey this information to the family lies with the proband. Current practice falls short, requiring additional support from the clinician and multidisciplinary team. Communication is a 2-part iterative process, reliant on both the understanding of the probands and their ability to effectively communicate with relatives. With the surge of high-throughput genetic testing, results generated are increasingly complex, making the task of communication more challenging. Here we discuss 3 key issues. First, the probabilistic nature of genetic test results means uncertainty is inherent to the practice. Second, secondary findings may arise. Third, personal preferences, values, and family dynamics also come into play and must be acknowledged when considering how best to support effective communication. Here we provide insight into the challenges and provide practical advice for clinicians to support effective family communication. These strategies include acknowledging and managing genetic uncertainty, genetic counseling and informed consent, and consideration of personal and familial barriers to effective communication. We will explore the potential for developing resources to assist clinicians in providing patients with sufficient knowledge and support to communicate complex information to their at-risk relatives. Specialized multidisciplinary clinics remain the best equipped to manage patients and families with inherited heart rhythm disorders given the need for a high level of information and support.