Recreational and Occupational Physical Activity and Risk of Adverse Events in Truncating Founder Variant Carriers.

Background: founder variants cause hypertrophic cardiomyopathy leading to heart failure and malignant ventricular arrhythmias. Exercise is typically regarded as a risk factor for disease expression although evidence is conflicting. Stratifying by type of exercise may discriminate low- from high-risk activities in these patients.

Penetrance and Prognosis of MYH7 Variant-Associated Cardiomyopathies: Results From a Dutch Multicenter Cohort Study.

Background: MYH7 variants cause hypertrophic cardiomyopathy (HCM), noncompaction cardiomyopathy (NCCM), and dilated cardiomyopathy (DCM). Screening of relatives of patients with genetic cardiomyopathy is recommended from 10 to 12 years of age onward, irrespective of the affected gene.

Objectives: This study sought to study the penetrance and prognosis of MYH7 variant-associated cardiomyopathies.

MYH7 p.(Arg1712Gln) is pathogenic founder variant causing hypertrophic cardiomyopathy with overall relatively delayed onset.

Introduction: The MYH7 c.5135G > A p.(Arg1712Gln) variant has been identified in several patients worldwide and is classified as pathogenic in the ClinVar database.

A Systematic Analysis of the Clinical Outcome Associated with Multiple Reclassified Desmosomal Gene Variants in Arrhythmogenic Right Ventricular Cardiomyopathy Patients.

The presence of multiple pathogenic variants in desmosomal genes (DSC2, DSG2, DSP, JUP, and PKP2) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been linked to a severe phenotype. However, the pathogenicity of variants is reclassified frequently, which may result in a changed clinical risk prediction. Here, we present the collection, reclassification, and clinical outcome correlation for the largest series of ARVC patients carrying multiple desmosomal pathogenic variants to date (n = 331).

Expanding the phenotype of anauxetic dysplasia caused by biallelic NEPRO mutations: A case report.

The cartilage hair hypoplasia and anauxetic dysplasia (CHH-AD) spectrum encompasses a group of rare skeletal disorders, with anauxetic dysplasia (ANXD) at the most severe end of the spectrum. Biallelic variants in RMRP, POP1, and NEPRO (C3orf17) have previously been associated with the three currently recognized ANXD types. Generally, all types are characterized by severe short stature, brachydactyly, skin laxity, joint hypermobility and dislocations, and extensive skeletal abnormalities visible on radiological evaluation.

Untargeted Metabolomics Identifies Potential Hypertrophic Cardiomyopathy Biomarkers in Carriers of Founder Variants.

Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disease, commonly caused by pathogenic variants, and a significant cause of sudden cardiac death. Severity is highly variable, with incomplete penetrance among genotype-positive family members. Previous studies demonstrated metabolic changes in HCM.

Phenotypic and Genetic Factors Associated with Absence of Cardiomyopathy Symptoms in PLN:c.40_42delAGA Carriers.

The c.40_42delAGA variant in the phospholamban gene (PLN) has been associated with dilated and arrhythmogenic cardiomyopathy, with up to 70% of carriers experiencing a major cardiac event by age 70. However, there are carriers who remain asymptomatic at older ages.

Variant Location Is a Novel Risk Factor for Individuals With Arrhythmogenic Cardiomyopathy Due to a Desmoplakin () Truncating Variant.

Background: Truncating variants in desmoplakin (tv) are an important cause of arrhythmogenic cardiomyopathy; however the genetic architecture and genotype-specific risk factors are incompletely understood. We evaluated phenotype, risk factors for ventricular arrhythmias, and underlying genetics of tv cardiomyopathy.

Methods: Individuals with tv and any cardiac phenotype, and their gene-positive family members were included from multiple international centers.

KBTBD13 is a novel cardiomyopathy gene.

KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.

SEPT-GD: A decision tree to prioritise potential RNA splice variants in cardiomyopathy genes for functional splicing assays in diagnostics.

Background: Splice prediction algorithms currently used in routine DNA diagnostics have limited sensitivity and specificity, therefore many potential splice variants are classified as variants of uncertain significance (VUSs). However, functional assessment of VUSs to test splicing is labour-intensive and time-consuming. We developed a decision tree to prioritise potential splice variants for functional studies and functionally verified the outcome of the decision tree.

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy.

Aims: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients.

Methods And Results: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.

Functional investigation of two simultaneous or separately segregating DSP variants within a single family supports the theory of a dose-dependent disease severity.

Desmoplakin (DP) is an important component of desmosomes, essential in cell-cell connecting structures in stress-bearing tissues. Over the years, many hundreds of pathogenic variants in DSP have been associated with different cutaneous and cardiac phenotypes or a combination, known as a cardiocutaneous syndrome. Of less than 5% of the reported DSP variants, the effect on the protein has been investigated.

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

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.

Case series, chemotherapy-induced cardiomyopathy: mind the family history!

Background: Cardiotoxicity presenting as cardiomyopathy is a common side effect in cancer treatment especially with anthracyclines. The role of genetic predisposition is still being investigated.

Case Summary: Four unrelated patients with a familial burden for cardiac disease, who developed cardiomyopathy after anthracycline treatment are presented.

Dynamic loading of human engineered heart tissue enhances contractile function and drives a desmosome-linked disease phenotype.

The role that mechanical forces play in shaping the structure and function of the heart is critical to understanding heart formation and the etiology of disease but is challenging to study in patients. Engineered heart tissues (EHTs) incorporating human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes have the potential to provide insight into these adaptive and maladaptive changes. However, most EHT systems cannot model both preload (stretch during chamber filling) and afterload (pressure the heart must work against to eject blood).

The genetic architecture of Plakophilin 2 cardiomyopathy.

Purpose: The genetic architecture of Plakophilin 2 (PKP2) cardiomyopathy can inform our understanding of its variant pathogenicity and protein function.

Methods: We assess the gene-wide and regional association of truncating and missense variants in PKP2 with arrhythmogenic cardiomyopathy (ACM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) specifically. A discovery data set compares genetic testing requisitions to gnomAD.

Sudden Cardiac Death Prediction in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Collaboration.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with ventricular arrhythmias (VA) and sudden cardiac death (SCD). A model was recently developed to predict incident sustained VA in patients with ARVC. However, since this outcome may overestimate the risk for SCD, we aimed to specifically predict life-threatening VA (LTVA) as a closer surrogate for SCD.

Publisher Correction: Relevance of Titin Missense and Non-Frameshifting Insertions/Deletions Variants in Dilated Cardiomyopathy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Prevalence and Prognostic Impact of Pathogenic Variants in Patients With Dilated Cardiomyopathy Referred for Ventricular Tachycardia Ablation.

Objectives: This study aimed to assess the frequency of (likely) pathogenic variants (LP/Pv) among dilated cardiomyopathy (DCM) ventricular tachycardia (VT) patients referred for CA and their impact on procedural outcome and long-term prognosis.

Background: The prevalence of genetic variants associated with monomorphic VT among DCM is unknown.

Methods: Ninety-eight consecutive patients (age 56 ± 15 years; 84% men, left ventricular ejection fraction [LVEF] 39 ± 12%) referred for DCM-VT ablation were included.

Goldberg-Shprintzen syndrome is determined by the absence, or reduced expression levels, of KIFBP.

Goldberg-Shprintzen syndrome (GOSHS) is caused by loss of function variants in the kinesin binding protein gene (KIFBP). However, the phenotypic range of this syndrome is wide, indicating that other factors may play a role. To date, 37 patients with GOSHS have been reported.

The effect of tropomyosin variants on cardiomyocyte function and structure that underlie different clinical cardiomyopathy phenotypes.

Background - Variants within the alpha-tropomyosin gene (TPM1) cause dominantly inherited cardiomyopathies, including dilated (DCM), hypertrophic (HCM) and restrictive (RCM) cardiomyopathy. Here we investigated whether TPM1 variants observed in DCM and HCM patients affect cardiomyocyte physiology differently. Methods - We identified a large family with DCM carrying a recently identified TPM1 gene variant (T201M) and a child with RCM with compound heterozygote TPM1 variants (E62Q and M281T) whose family members carrying single variants show diastolic dysfunction and HCM.