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BACKGROUND: Genetic variants in TNNI3K (troponin-I interacting kinase) have previously been associated with dilated cardiomyopathy (DCM), cardiac conduction disease, and supraventricular tachycardias. However, the link between TNNI3K variants and these cardiac phenotypes shows a lack of consensus concerning phenotype and protein function. METHODS: We describe a systematic retrospective study of a cohort of patients undergoing genetic testing for cardiac arrhythmias and cardiomyopathy including TNNI3K . We further performed burden testing of TNNI3K in the UK Biobank. For 2 novel TNNI3K variants, we tested cosegregation. TNNI3K kinase function was estimated by TNNI3K autophosphorylation assays. RESULTS: We demonstrate enrichment of rare coding TNNI3K variants in DCM patients in the Amsterdam cohort. In the UK Biobank, we observed an association between TNNI3K missense (but not loss-of-function) variants and DCM and atrial fibrillation. Furthermore, we demonstrate genetic segregation for 2 rare variants, TNNI3K-p.Ile512Thr and TNNI3K-p.His592Tyr, with phenotypes consisting of DCM, cardiac conduction disease, and supraventricular tachycardia, together with increased autophosphorylation. In contrast, TNNI3K-p.Arg556_Asn590del, a likely benign variant, demonstrated depleted autophosphorylation. CONCLUSIONS: Our findings demonstrate an increased burden of rare coding TNNI3K variants in cardiac patients with DCM. Furthermore, we present 2 novel likely pathogenic TNNI3K variants with increased autophosphorylation, suggesting that enhanced autophosphorylation is likely to drive pathogenicity.

Background: Variants in KCNH2, encoding the human ether a-go-go (hERG) channel that is responsible for the rapid component of the cardiac delayed rectifier K+ current (IKr), are causal to long QT syndrome type 2 (LQTS2). We identified eight index patients with a new variant of unknown significance (VUS), KCNH2:c.2717C > T:p.(Ser906Leu). We aimed to elucidate the biophysiological effect of this variant, to enable reclassification and consequent clinical decision-making. Methods: A genotype–phenotype overview of the patients and relatives was created. The biophysiological effects were assessed independently by manual-, and automated calibrated patch clamp. HEK293a cells expressing (i) wild-type (WT) KCNH2, (ii) KCNH2-p.S906L alone (homozygous, Hm) or (iii) KCNH2-p.S906L in combination with WT (1:1) (heterozygous, Hz) were used for manual patching. Automated patch clamp measured the variants function against known benign and pathogenic variants, using Flp-In T-rex HEK293 KCNH2-variant cell lines. Results: Incomplete penetrance of LQTS2 in KCNH2:p.(Ser906Leu) carriers was observed. In addition, some patients were heterozygous for other VUSs in CACNA1C, PKP2, RYR2 or AKAP9. The phenotype of carriers of KCNH2:p.(Ser906Leu) ranged from asymptomatic to life-threatening arrhythmic events. Manual patch clamp showed a reduced current density by 69.8 and 60.4% in KCNH2-p.S906L-Hm and KCNH2-p.S906L-Hz, respectively. The time constant of activation was significantly increased with 80.1% in KCNH2-p.S906L-Hm compared with KCNH2-WT. Assessment of KCNH2-p.S906L-Hz by calibrated automatic patch clamp assay showed a reduction in current density by 35.6%. Conclusion: The reduced current density in the KCNH2-p.S906L-Hz indicates a moderate loss-of-function. Combined with the reduced penetrance and variable phenotype, we conclude that KCNH2:p.(Ser906Leu) is a low penetrant likely pathogenic variant for LQTS2.

Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disease, commonly caused by pathogenic MYBPC3 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. We aimed to identify metabolite profiles associated with disease severity in carriers of MYBPC3 founder variants using direct-infusion high-resolution mass spectrometry in plasma of 30 carriers with a severe phenotype (maximum wall thickness ≥20 mm, septal reduction therapy, congestive heart failure, left ventricular ejection fraction

Background With advances in sequencing technologies, increasing numbers of people are being informed about a genetic disease identified in their family. In current practice, probands (the first person in a family in whom a genetic predisposition is identified) are asked to inform at-risk relatives about the diagnosis. However, previous research has shown that relatives are sometimes not informed due to barriers such as family conflicts. Research on family communication in genetic diseases aims to explore the difficulties encountered in informing relatives and to identify ways to support probands in this. Main body Research on family communication may also reveal that participants did not inform their relatives about the risk of a serious genetic condition, even when preventive and treatment options are available. Researchers may then face a dilemma: Do they need to warn at-risk relatives about the finding? Or do they keep silent due to prior confidentiality agreements with study participants? Conclusions We believe that the absolute confidence promised to research participants outweighs the interests of their relatives, even though it can be claimed that relatives at risk of a genetic disease do, in principle, have a right to know information collected about their health. Not respecting confidentiality agreements could cause distrust between researchers and research participants and possibly harm the relationship between probands and relatives. Relatives' health interests can still be taken into account without jeopardizing participant trust, by considering alternative scenarios, including sharing general study findings on the barriers participants experience with their healthcare professionals and by offering participants psychosocial support for family communication.

Cantu Syndrome (CS), [OMIM #239850] is characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. CS is caused by gain-of-function (GOF) variants in the KCNJ8 or ABCC9 genes that encode pore-forming Kir6.1 and regulatory SUR2 subunits of ATP-sensitive potassium (KATP) channels. Many subjects with CS also present with the complication of lymphedema. A previously uncharacterized, heterozygous ABCC9 variant, p.(Leu1055_Glu1058delinsPro), termed indel1055, was identified in an individual diagnosed with idiopathic lymphedema. The variant was introduced into the equivalent position of rat SUR2A, and inside-out patches were used to characterize the KATP channels formed by Kir6.2 and WT or mutant SUR2A subunits coexpressed in Cosm6 cells. The indel1055 variant causes gain-of-function of the channel, with an increase of the IC50 for ATP inhibition compared to WT. Retrospective consideration of this individual reveals clear features of Cantu Syndrome. An additional heterozygous ABCC9 variant, p.(Ile419Thr), was identified in a second individual diagnosed with lymphedema. In this case, there were no additional features consistent with CS, and the properties of p.(Ile416Thr) (the corresponding mutation in rat SUR2A)--containing channels were not different from WT. This proof-of-principle study shows that idiopathic lymphedema may actually be a first presentation of otherwise unrecognized Cantu Syndrome, but molecular phenotyping of identified variants is necessary to confirm relevance.

Background: This study aimed to describe the current practice and results of genetic evaluation in Dutch children with dilated cardiomyopathy and to evaluate genotype-phenotype correlations that may guide prognosis. Methods: We performed a multicenter observational study in children diagnosed with dilated cardiomyopathy, from 2010 to 2017. Results: One hundred forty-four children were included. Initial diagnostic categories were idiopathic dilated cardiomyopathy in 67 children (47%), myocarditis in 23 (16%), neuromuscular in 7 (5%), familial in 18 (13%), inborn error of metabolism in 4 (3%), malformation syndrome in 2 (1%), and “other” in 23 (16%). Median follow-up time was 2.1 years [IQR 1.0–4.3]. Hundred-seven patients (74%) underwent genetic testing. We found a likely pathogenic or pathogenic variant in 38 children (36%), most often in MYH7 (n = 8). In 1 patient initially diagnosed with myocarditis, a pathogenic LMNA variant was found. During the study, 39 patients (27%) reached study endpoint (SE: all-cause death or heart transplantation). Patients with a likely pathogenic or pathogenic variant were more likely to reach SE compared with those without (hazard ratio 2.8; 95% CI 1.3–5.8, P = 0.007), while transplant-free survival was significantly lower ( P = 0.006). Clinical characteristics at diagnosis did not differ between the 2 groups. Conclusions: Genetic testing is a valuable tool for predicting prognosis in children with dilated cardiomyopathy, with carriers of a likely pathogenic or pathogenic variant having a worse prognosis overall. Genetic testing should be incorporated in clinical work-up of all children with dilated cardiomyopathy regardless of presumed disease pathogenesis.

The uptake of predictive DNA testing in families with a hereditary disease is

Supplemental Digital Content is available in the text., Background: Inherited cardiac conditions present with a wide range of symptoms and may even result in sudden cardiac death. Relatives of probands with a confirmed pathogenic genetic variant are advised predictive DNA testing to enable prevention and treatment. In 2 previous cohort studies of 115 probands with a pathogenic variant, family uptake of genetic counseling was assessed in the first year(s) after test result disclosure to the proband. This study assesses uptake in these cohorts in the 14 to 23 years following disclosure. Methods: Uptake was determined retrospectively using patient records. First-degree relatives, and second-degree relatives of a deceased first-degree relative suspected of having an inherited cardiac condition, were considered eligible. Results: Of 717 eligible relatives (598 first-degree and 119 second-degree relatives), 60% attended genetic counseling. Most of them (68.6%) attended genetic counseling in the first year. A total of 98.4% of counseled relatives pursued predictive DNA testing. A total of 49.2% was identified as carrier. Median time between disclosure to the proband and counseling of relatives was 6 months (range: 0–187 months). Attending genetic counseling was observed more frequently in first-degree relatives, female relatives, primary arrhythmia syndromes, relatives with manifest inherited cardiac condition, relatives without children and families with sudden cardiac death in first-degree relatives

Background: Next-generation sequencing gene panels are increasingly used for genetic diagnosis in inherited cardiac diseases. Besides pathogenic variants, multiple variants, variants of uncertain significance (VUS) and incidental findings can be detected. Such test results can be challenging for counselling and clinical decision making. Methods: We present patient cases to illustrate the challenges that can arise when unclear genetic test results are detected in cardiogenetic gene panels. Results: We identified three types of challenging gene panel results: 1) one or more VUS in combination with a pathogenic variant, 2) variants associated with another genetic heart disease, and 3) variants associated with a syndrome involving cardiac features. Conclusion: Large gene panels not only increase the detection rates of pathogenic variants but also of variants with uncertain pathogenicity, multiple variants and incidental findings. Gene panel results can be challenging for genetic counselling and require proper pre-test and post-test counselling. We advise evaluation of challenging cases by a multidisciplinary team.

Background Genetic heterogeneity is common in inherited cardiac diseases. Next-generation sequencing gene panels are therefore suitable for genetic diagnosis. We describe the results of implementation of cardiomyopathy and arrhythmia gene panels in clinical care. Methods We present detection rates for variants with unknown (class 3), likely (class 4), and certain (class 5) pathogenicity in cardiogenetic gene panels since their introduction into diagnostics. Results In 936 patients tested on the arrhythmia panel, likely pathogenic and pathogenic variants were detected in 8.8% (4.6% class 5; 4.2% class 4), and one or multiple class 3 variants in 34.8%. In 1970 patients tested on the cardiomyopathy panel, likely pathogenic and pathogenic variants were detected in 19.8% (12.0% class 5; 7.9% class 4), and one or multiple class 3 variants in 40.8%. Detection rates of all different classes of variants increased with the increasing number of genes on the cardiomyopathy gene panel. Multiple variants were detected in 11.7% and 28.5% of patients on the arrhythmia and cardiomyopathy panels respectively. In more recent larger versions of the cardiomyopathy gene panel the detection rate of likely pathogenic and pathogenic variants only slightly increased, but was associated with a large increase of class 3 variants. Conclusion Overall detection rates (class 3, 4, and 5 variants) in a diagnostic setting are 44% and 61% for the arrhythmia and cardiomyopathy gene panel respectively, with only a small minority of likely pathogenic and pathogenic variants (8.8% and 19.8% respectively). Larger gene panels can increase the detection rate of likely pathogenic and pathogenic variants, but mainly increase the frequency of variants of unknown pathogenicity. Electronic supplementary material The online version of this article (10.1007/s12471-019-1250-5) contains supplementary material, which is available to authorized users.

The heart muscle diseases hypertrophic (HCM) and dilated (DCM) cardiomyopathies are leading causes of sudden death and heart failure in young, otherwise healthy, individuals. We conducted genome-wide association studies and multi-trait analyses in HCM (1,733 cases), DCM (5,521 cases) and nine left ventricular (LV) traits (19,260 UK Biobank participants with structurally normal hearts). We identified 16 loci associated with HCM, 13 with DCM and 23 with LV traits. We show strong genetic correlations between LV traits and cardiomyopathies, with opposing effects in HCM and DCM. Two-sample Mendelian randomization supports a causal association linking increased LV contractility with HCM risk. A polygenic risk score explains a significant portion of phenotypic variability in carriers of HCM-causing rare variants. Our findings thus provide evidence that polygenic risk score may account for variability in Mendelian diseases. More broadly, we provide insights into how genetic pathways may lead to distinct disorders through opposing genetic effects.

In relatives of index patients with dilated cardiomyopathy and arrhythmogenic cardiomyopathy, early detection of disease onset is essential to prevent sudden cardiac death and facilitate early treatment of heart failure. However, the optimal screening interval and combination of diagnostic techniques are unknown. The clinical course of disease in index patients and their relatives is variable due to incomplete and age-dependent penetrance. Several biomarkers, electrocardiographic and imaging (echocardiographic deformation imaging and cardiac magnetic resonance imaging) techniques are promising non-invasive methods for detection of subclinical cardiomyopathy. However, these techniques need optimisation and integration into clinical practice. Furthermore, determining the optimal interval and intensity of cascade screening may require a personalised approach. To address this, the CVON-eDETECT (early detection of disease in cardiomyopathy mutation carriers) consortium aims to integrate electronic health record data from long-term follow-up, diagnostic data sets, tissue and plasma samples in a multidisciplinary biobank environment to provide personalised risk stratification for heart failure and sudden cardiac death. Adequate risk stratification may lead to personalised screening, treatment and optimal timing of implantable cardioverter defibrillator implantation. In this article, we describe non-invasive diagnostic techniques used for detection of subclinical disease in relatives of index patients with dilated cardiomyopathy and arrhythmogenic cardiomyopathy.

If undetected, inherited cardiac conditions can lead to sudden cardiac death, while treatment options are available. Predictive DNA testing is therefore advised for at-risk relatives, and probands are currently asked to inform relatives about this. However, fewer than half of relatives attend genetic counselling. In this trial, we compared a tailored approach to informing relatives, in which probands were asked whether they preferred relatives to be informed by themselves or by the genetic counsellor, with current practice. Our primary outcome was uptake of genetic counselling in relatives in the first year after test result disclosure. Secondary outcomes were evaluation of the approach and impact on psychological/family functioning measured 3 (T1) and 9 (T2) months post-disclosure via telephone interviews and questionnaires. We included 96 probands; 482 relatives were eligible for counselling and genetic testing. We observed no significant difference in uptake of genetic counselling between the control (38%) and the intervention (37%) group (p = 0.973). Nor were there significant differences between groups in impact on family/psychological functioning. Significantly more probands in the tailored group were satisfied (p = 0.001) and felt supported (p = 0.003) by the approach, although they also felt somewhat coerced to inform relatives (p < 0.001) and perceived room for improvement (p < 0.001). To conclude, we observed no differences in uptake and impact on family/psychological functioning between the current and tailored approach, but probands in the tailored group more often felt satisfied. Further research on barriers to relatives attending genetic counselling and on how to optimize the provision of a tailored approach is needed.

Introduction: Hypertrophic (HCM) and dilated (DCM) cardiomyopathies are leading causes of sudden death and heart failure requiring transplantation in young individuals. While some cases have a monogenic underlying cause, the majority remain unexplained. Objective: To better understand the contribution of common genetic variants in susceptibility and severity of cardiomyopathy. Methods: We conducted three genome-wide association studies (GWAS) and multi-trait analyses in European-ancestry individuals, including a HCM (1,733 cases) and DCM meta-analyses (5,521 cases), and a GWAS of 9 left ventricular (LV) traits in 19,260 healthy participants from the UK Biobank that underwent cardiac magnetic resonance imaging. We investigated genetic correlations between LV traits, HCM and DCM using LD score regression. We used two-sample mendelian randomization (MR) to assess the causal relationship of increased LV contractility with HCM risk. Lastly, we derived a polygenic risk score and assessed whether it modulates maximal LV wall thickness (maxLVWT) and clinical events in 368 sarcomeric mutation carriers, using linear and Cox mixed effects models, respectively. Results: We identified 16 genetic loci (15 novel) associated with HCM, 13 loci (7 novel) associated with DCM, and 23 loci associated with LV traits. We showed strong genetic correlations between LV volumes and contractility traits in the general population and cardiomyopathies, with opposing effects in HCM and DCM. Using MR, we demonstrated a causal association linking increased LV contractility with HCM risk and estimated that each unit (1%) increase in LV ejection fraction increases the risk of HCM by 37% (95% CI 10%-69%, P=0.004). Lastly, a polygenic risk score (PRS HCM ) derived from the HCM GWAS was associated with maxLVWT (P=0.0001) and clinical events (P=0.009) in carriers of HCM-causing rare variants. Conclusion: Our findings highlight the contribution of common genetic variants in susceptibility for HCM and DCM, and in severity in sarcomeric mutation carriers. Our data also point to increased LV contractility as an important mechanism of HCM independently of sarcomere activating rare variants, and highlight the potential clinical relevance of PRS for risk stratification in HCM.

Background In the past decade, we and others have reported three families with rare genetic variants in TNNI3K, encoding the cardiac-specific troponin-I interacting kinase (TNNI3K), co-segregating with a mixed, but highly penetrant, cardiac phenotype that features predominant atrial/junctional tachycardia occurring in combination with cardiac conduction disease and dilated cardiomyopathy. We demonstrated that while the p.Thr539Ala and p.Gly526Asp TNNI3K variants had decreased auto-phosphorylation activity the p.Glu768Lys variant, present in 3 independent families, leads to increased auto-phosphorylation levels, in line with the finding that increased levels of Tnni3k expression are associated with slower atrial-ventricular conduction in mice. Objective Identifying new genetic variants in the TNNI3K gene associated with cardiac disease and assessing their impact on TNNI3K auto-phosphorylation levels. Methods Through next generation sequencing of a panel of genes associated with cardiac disease we assessed TNNI3K in patients with cardiac arrhythmias and cardiomyopathies. All variants identified were assessed in vitro for effects on auto-phosphorylation. Briefly, wild-type and mutant TNNI3K constructs were transfected into HEK293 cells, protein was extracted after 48 hours and analyzed with anti-flag and anti-phospho-tyrosine antibodies on Western blot. Results We identified 7 novel and rare variants in TNNI3K in 11 additional probands, with predominantly cardiac conduction disease, with or without dilated cardiomyopathy, and atrial-ventricular-re-entry-tachycardia (AVNRT). Of these, multiple variants were found to have aberrant auto-phosphorylation including almost absent auto-phosphorylation capacity for one (TNNI3K-p.Val510Leu). All three-independent wild type TNNI3K transfected HEK293 cell lysates showed similar phosphorylated TNNI3K levels and the kinase-dead negative control demonstrated no phosphorylation activity. Conclusion We here present 7 novel genetic variants in TNNI3K in patients with a remarkable overlap in cardiac phenotype consisting mainly of AVNRT and cardiac conduction disease. We further show that some of these variants alter the auto-phosphorylation of TNNI3K. These results indicate a more prevalent role of variants in TNNI3K in human cardiac disease and a possible in vitro functional assay to assess the pathogenicity of such variants. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Dutch Research Council (NWO Talent Scheme VIDI-91718361)

Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high‐throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC‐associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrimental for muscle function, as found in HCM and MFM. Variants associated with HCM are predominantly missense variants, which cluster in the ROD2 domain. This domain is important for binding to the sarcomere and to ensure appropriate cell signaling. We here review FLNC genotype–phenotype correlations based on available evidence., The location of causative variants leading to the filaminopathies A are mapped onto FLNA protein monomers. Variants leading to ‘loss‐of‐function’ disorders (left monomer) and ‘gain‐of‐function’ disorders (right monomer) can clearly be seen to cluster. ‘Hotspot’ regions are marked with larger symbols. PH: periventricular heterotopia, CIPX: congenital intestinal pseudo‐obstruction, IMT: isolated macrothrombocytopenia, FCMPD: familial cardiac myxomatous polyvalvular dystrophy, OPD: otopalatodigital syndrome, FMD: frontometaphyseal dysplasia, CKCO: condition comprising contractures, keloid, cardiac defects and optic anomalies, MNS: Melnick‐Needles syndrome, DCD: digitocutaneous dysplasia, ABD: actin‐binding domain, CHD: calponin homology domain, H: hinge.

AimsIdiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac arrest. Implantable cardioverter-defibrillator (ICD) implantation is currently the only treatment option. Limited data are available on the prevalence and complications of ICD therapy in these patients. We sought to investigate ICD therapy and its complications in patients with IVF.Methods and resultsPatients were selected from a national registry of IVF patients. Patients in whom no underlying diagnosis was found during follow-up were eligible for inclusion. Recurrence of ventricular arrhythmia (VA) was derived from medical and ICD records, electrogram records of ICD therapies were used to differentiate between appropriate or inappropriate interventions. Independent predictors for appropriate ICD shock were calculated using cox regression. In 217 IVF patients, recurrence of sustained VAs occurred in 66 patients (30%) during a median follow-up period of 6.1 years. Ten patients died (4.6%). Thirty-eight patients (17.5%) experienced inappropriate ICD therapy, and 32 patients (14.7%) had device-related complications. Symptoms before cardiac arrest [hazard ratio (HR): 2.51, 95% confidence interval (CI): 1.48–4.24], signs of conduction disease (HR: 2.27, 95% CI: 1.15–4.47), and carrier of the DPP6 risk haplotype (HR: 3.24, 1.70–6.17) were identified as independent predictors of appropriate shock occurrence.ConclusionImplantable cardioverter-defibrillator therapy is an effective treatment in IVF, treating recurrences of potentially lethal VAs in approximately one-third of patients during long-term follow-up. However, device-related complications and inappropriate shocks were also frequent. We found significant predictors for appropriate ICD therapy. This may imply that these patients require additional management to prevent recurrent events.

BackgroundMutations in genes encoding ion channels or sarcomeric proteins are an important cause of hereditary cardiac disease. However, the severity of the resultant disease varies considerably even among those with an identical mutation. Such clinical variation is often thought to be explained largely by differences in genetic background or ‘modifier genes’. We aimed to test the prediction that identical genetic backgrounds result in largely similar clinical expression of a cardiac disease causing mutation, by studying the clinical expression of mutations causing cardiac disease in monozygotic twins.MethodsWe compared first available clinical information on 46 monozygotic twin pairs and 59 control pairs that had either a hereditary cardiomyopathy or channelopathy.ResultsDespite limited power of this study, we found significant heritability for corrected QT interval (QTc) in long QT syndrome (LQTS). We could not detect significant heritability for structural traits, but found a significant environmental effect on thickness of the interventricular septum in hypertrophic cardiomyopathy.ConclusionsOur study confirms previously found robust heritability for electrical traits like QTc in LQTS, and adds information on low or lacking heritability for structural traits in heritable cardiomyopathies. This may steer the search for genetic modifiers in heritable cardiac disease.

IntroductionIn current practice, probands are asked to inform relatives about the possibility of predictive DNA testing when a pathogenic variant causing an inherited cardiac condition (ICC) is identified. Previous research on the uptake of genetic counselling and predictive DNA testing in relatives suggests that not all relatives are sufficiently informed. We developed a randomised controlled trial to evaluate the effectiveness of a tailored approach in which probands decide together with the genetic counsellor which relatives they inform themselves and which relatives they prefer to have informed by the genetic counsellor. Here, we present the study protocol of this randomised controlled trial.MethodsA multicentre randomised controlled trial with parallel-group design will be conducted in which an intervention group receiving the tailored approach will be compared with a control group receiving usual care. Adult probands diagnosed with an ICC in whom a likely pathogenic or pathogenic variant is identified will be randomly assigned to the intervention or control group (total sample: n=85 probands). Primary outcomes are uptake of genetic counselling and predictive DNA testing by relatives (total sample: n=340 relatives). Secondary outcomes are appreciation of the approach used and impact on familial and psychological functioning, which will be assessed using questionnaires. Relatives who attend genetic counselling will be asked to fill out a questionnaire as well.Ethics and disseminationEthical approval was obtained from the Medical Ethical Committee of the Amsterdam University Medical Centres (MEC 2017-145), the Netherlands. All participants will provide informed consent prior to participation in the study. Results of the study on primary and secondary outcome measures will be published in peer-reviewed journals.Trial registration numberNTR6657; Pre-results.

BACKGROUND Familial idiopathic ventricular fibrillation (IVF) is a severe disease entity and is notoriously difficult to manage because there are no clinical risk indicators for premature cardiac arrest. Previously, we identified a link between familial IVF and a risk haplotype on chromosome 7q36 (involving the arrhythmia gene DPP6). OBJECTIVE The purpose of this study was to expand our knowledge of familial IVF and to discuss its (extended) clinical characteristics. METHODS We studied 601 family members and probands: 286 DPP6 risk-haplotype positive (haplotype-positive) and 315 DPP6 risk-haplotype negative (haplotype-negative) individuals. Clinical parameters, a combination of all-cause mortality and (aborted) cardiac arrest and differences between haplotype-positives and haplotype-negatives, were evaluated. RESULTS There were no differences in electrocardiographic indices between haplotype-positives and haplotype-negatives, or between haplotype-positives with or without events. Cardiac magnetic resonance documented slightly larger ventricular volumes in haplotype-positives compared to controls (P

Contains fulltext : 167854.pdf (Publisher’s version ) (Open Access) AIMS: Phenotypic heterogeneity and incomplete penetrance are common in patients with hypertrophic cardiomyopathy (HCM). We aim to improve the understanding in genotype-phenotype correlations in HCM, particularly the contribution of an MYL2 founder mutation and risk factors to left ventricular hypertrophic remodelling. METHODS AND RESULTS: We analysed 14 HCM families of whom 38 family members share the MYL2 c.64G > A [p.(Glu22Lys)] mutation and a common founder haplotype. In this unique cohort, we investigated factors influencing phenotypic outcome in addition to the primary mutation. The mutation alone showed benign disease manifestation with low penetrance. The co-presence of additional risk factors for hypertrophy such as hypertension, obesity, or other sarcomeric gene mutation increased disease penetrance substantially and caused HCM in 89% of MYL2 mutation carriers (P = 0.0005). The most prominent risk factor was hypertension, observed in 71% of mutation carriers with HCM and an additional risk factor. CONCLUSION: The MYL2 mutation c.64G > A on its own is incapable of triggering clinical HCM in most carriers. However, the presence of an additional risk factor for hypertrophy, particularly hypertension, adds to the development of HCM. Early diagnosis of risk factors is important for early treatment of MYL2 mutation carriers and close monitoring should be guaranteed in this case. Our findings also suggest that the presence of hypertension or another risk factor for hypertrophy should not be an exclusion criterion for genetic studies.

The pathogenicity of previously published disease-associated genes and variants is sometimes questionable. Large-scale, population-based sequencing studies have uncovered numerous false assignments of pathogenicity. Misinterpretation of sequence variants may have serious implications for the patients and families involved, as genetic test results are increasingly being used in medical decision making In this study, we assessed the role of the calreticulin-3 gene (CALR3) in cardiomyopathy. CALR3 has been included in several cardiomyopathy gene panels worldwide. Its inclusion is based on a single publication describing two missense variants in patients with hypertrophic cardiomyopathy. In our national cardiomyopathy cohort (n = 6154), we identified 17 unique, rare heterozygous CALR3 variants in 48 probands. Overall, our patient cohort contained a significantly higher number of rare CALR3 variants compared to the ExAC population (p = 0.0036). However, after removing a potential Dutch founder variant, no statistically significant difference was found (p = 0.89). In nine probands, the CALR3 variant was accompanied by a disease-causing variant in another, well-known cardiomyopathy gene. In three families, the CALR3 variant did not segregate with the disease. Furthermore, we could not demonstrate calreticulin-3 protein expression in myocardial tissues at various ages. On the basis of these findings, it seems highly questionable that variants in CALR3 are a monogenic cause of cardiomyopathy.

With interest, we read the article by Servatius et al1 presenting a 36-year-old man with sick sinus syndrome, left ventricular noncompaction, mood and anxiety disorders, and ventricular fibrillation because of …

Background: Identification of people with hypertrophic cardiomyopathy (HCM) who are at risk of sudden cardiac death (SCD) and require a prophylactic implantable cardioverter defibrillator is challenging. In 2014, the European Society of Cardiology proposed a new risk stratification method based on a risk prediction model (HCM Risk-SCD) that estimates the 5-year risk of SCD. The aim was to externally validate the 2014 European Society of Cardiology recommendations in a geographically diverse cohort of patients recruited from the United States, Europe, the Middle East, and Asia. Methods: This was an observational, retrospective, longitudinal cohort study. Results: The cohort consisted of 3703 patients. Seventy three (2%) patients reached the SCD end point within 5 years of follow-up (5-year incidence, 2.4% [95% confidence interval {CI}, 1.9–3.0]). The validation study revealed a calibration slope of 1.02 (95% CI, 0.93–1.12), C-index of 0.70 (95% CI, 0.68–0.72), and D-statistic of 1.17 (95% CI, 1.05–1.29). In a complete case analysis (n= 2147; 44 SCD end points at 5 years), patients with a predicted 5-year risk of Conclusions: This study confirms that the HCM Risk-SCD model provides accurate prognostic information that can be used to target implantable cardioverter defibrillator therapy in patients at the highest risk of SCD.

Background: Accurate estimates of survival are indispensable for cardiologists, clinical geneticists, and genetic counselors dealing with families with an inherited cardiac disease. However, a bias towards a more severe disease with a worse outcome in the first publications may not accurately represent the actual survival forecast. We, therefore, evaluated the effect of ascertainment bias on survival in 3 different inherited cardiac diseases (idiopathic ventricular fibrillation, SCN5A overlap syndrome, and arrhythmogenic cardiomyopathy) caused by a founder mutation. Methods: We collected mortality data from mutation-positive subjects with either DPP6 -associated idiopathic ventricular fibrillation, SCN5A overlap syndrome, and PLN -R14del-mediated arrhythmogenic cardiomyopathy >2 to 10 years of ongoing clinical/cascade genetic screening. Results: The median age of survival in DPP6 mutation-positive subjects increased from 44.6 years in the original cohort from 2008 (n=60; 95% CI, 36.8–52.4 years) to 68.2 years in the extended cohort from 2012 (n=235; 95% CI, 64.6–71.7 years; P SCN5A overlap syndrome, survival increased from 56.1 years in 1999 (n=86; 95% CI, 48.0–64.2 years) to 69.7 years in 2009 (n=197; 95% CI, 61.3–78.2 years; P =0.049). In PLN -R14del positive patients, the median age of survival increased from 63.5 years in 2010 (n=89; 95% CI, 59.1–68.0 years) to 65.2 years in 2012 (n=370; 95% CI, 62.0–68.3 years; P =0.046). Conclusions: The median age of survival in 3 different inherited cardiac diseases with an established pathogenic substrate significantly increased once genetic testing and cascade screening extended, after the first publication that elucidated the discovery of the disease-susceptibility gene/mutation. This underscores the direct and negative influence of ascertainment bias on survival forecasts and the importance of ongoing clinical/genetic follow-up to establish the most accurate disease prognosis for genetically mediated heart diseases.

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder that affects over one in 500 persons worldwide. The autosomal dominant transmission of HCM implies that many relatives are at risk for HCM associated morbidity and mortality, therefore genetic testing and counselling is of great importance. However, in only 50-60% of the patients a mutation is found, which hampers predictive genetic testing in relatives. In HCM patients in whom the causal mutation has not been identified (yet), phenocopies of HCM - i.e. diseases that mimic HCM - could be responsible for the HCM phenotype. One of the HCM phenocopies is transthyretin amyloidosis (ATTR), caused by mutations in the transthyretin (TTR) gene. From 697 HCM index patients referred to our cardiogenetics outpatient clinic and tested for HCM associated genes between January 1997 and December 2012, we selected the ones without a detected causal mutation (n = 345). In these patients, additional DNA analysis of the TTR gene was performed. In four patients (1.2%), a TTR mutation was detected (E7G, V30M, T119M, V122I). The E7G mutation is probably a non-pathogenic mutation. The T119M mutation is a known TTR mutation, but does not cause a cardiac phenotype. So in two (0.6%) patients, TTR analysis identified the cause of their HCM. ATTR should always be considered in patients with unexplained HCM, especially because of the great benefit of an early diagnosis regarding treatment and prognosis

Aims Mutations in the lamin A/C gene (LMNA) cause a variety of clinical phenotypes, including dilated cardiomyopathy. LMNA is one of the most prevalent mutated genes in dilated cardiomyopathy, and is associated with a high risk of arrhythmias, sudden cardiac death, and heart failure. There are few data on the impact of age and gender on cardiac disease penetrance and mortality. Methods and results In a multicentre cohort of 269 LMNA mutation carriers, we evaluated gender-specific penetrance of cardiac involvement and major cardiac events. All-cause mortality of mutation carriers [standardized mortality ratio (SMR)] was determined. Cardiac disease penetrance was age dependent and almost complete at the age of 70 years. The presence of an LVEF ≤45% was significantly higher in men (P < 0.001). However, there was no difference between genders in the prevalence of atrioventricular block, atrial tachyarrhythmias, and non-sustained ventricular tachycardia. Malignant ventricular arrhythmias (26% vs. 8%) and end-stage heart failure (28% vs. 14%) were more common in men than in women (P < 0.001 and P = 0.006, respectively). All-cause mortality of mutation carriers was significantly increased [SMR 4.0, 95% confidence interval (CI) 2.8–5.2] between the ages of 15 and 75 years. Mortality in men was higher than in women (hazard ratio 2.2, 95% CI 1.2–4.3). Conclusions This large cohort of LMNA mutation carriers demonstrates a high cardiac disease penetrance and a high mortality in mutation carriers. Male mutation carriers have a worse prognosis due to a higher prevalence of malignant ventricular arrhythmias and end-stage heart failure.

BackgroundLamin A/C (LMNA) mutation carriers suffer from a variety of clinical phenotypes, including dilated cardiomyopathy (DCM). Although it has been suggested that carriers are at risk for thromboembolic complications, it is unknown whether this risk is higher than can be expected from the underlying cardiac abnormalities. The purpose of this study was to determine whether a LMNA mutation is associated with an increased risk of thromboembolic complications.MethodsWe compared a cohort of 76 LMNA mutation carriers with a cohort of 224 idiopathic DCM patients without a LMNA mutation, with respect to the prevalence of arterial and venous thromboembolic complications. Furthermore, we carried out a case–control study to explore whether a prothrombotic phenotype was present in LMNA mutation carriers without DCM or atrial tachyarrhythmias (n=14) and compared this with mutation negative relatives (n=13).ResultsThe prevalence of thromboembolic complications was higher in the cohort of LMNA mutation carriers than in DCM patients (22 vs 11%; p

Left ventricular noncompaction (LVNC) is a relatively common genetic cardiomyopathy, characterized by prominent trabeculations with deep intertrabecular recesses in mainly the left ventricle. Although LVNC often occurs in an isolated entity, it may also be present in various types of congenital heart disease (CHD). The most prevalent CHD in LVNC is Ebstein anomaly, which is a rare form of CHD characterized by apical displacement and partial fusion of the septal and posterior leaflet of the tricuspid valve with the ventricular septum. Several reports of sporadic as well as familial cases of Ebstein anomaly associated with LVNC have been reported. Recent studies identified mutations in the MYH7 gene, encoding the sarcomeric β-myosin heavy chain protein, in patients harboring this specific phenotype. Here, we will review the association between Ebstein anomaly, LVNC and mutations in MYH7, which seems to represent a subtype of Ebstein anomaly with autosomal dominant inheritance and variable penetrance.

Background Genetic evaluation of cardiomyopathies poses a challenge. Multiple genes are involved but no clear genotype–phenotype correlations have been found so far. In the past, genetic evaluation for hypertrophic (HCM) and dilated (DCM) cardiomyopathies was performed by sequential screening of a very limited number of genes. Recent developments in sequencing have increased the throughput, enabling simultaneous screening of multiple genes for multiple patients in a single sequencing run. Objective Development and implementation of a next generation sequencing (NGS) based genetic test as replacement for Sanger sequencing. Methods and Results In order to increase the number of genes that can be screened in a shorter time period, we enriched all exons of 23 of the most relevant HCM and DCM related genes using on-array multiplexed sequence capture followed by massively parallel pyrosequencing on the GS-FLX Titanium. After optimisation of array based sequence capture it was feasible to reliably detect a large panel of known and unknown variants in HCM and DCM patients, whereby the unknown variants could be confirmed by Sanger sequencing. Conclusions The rate of detection of (pathogenic) variants in both HCM and DCM patients was increased due to a larger number of genes studied. Array based target enrichment followed by NGS showed the same accuracy as Sanger sequencing. Therefore, NGS is ready for implementation in a diagnostic setting.

With more than 40 dilated cardiomyopathy (DCM)-related genes known, genetic analysis of patients with idiopathic DCM is costly and time-consuming. We describe the yield from genetic analysis in DCM patients in a large Dutch cohort. We collected cardiological and neurological evaluations, family screenings, and genetic analyses for 418 index patients with idiopathic DCM. We identified 35 (putative) pathogenic mutations in 82 index patients (20%). The type of DCM influenced the yield, with mutations found in 25% of familial DCM cases, compared with 8% of sporadic DCM cases and 62% of cases where DCM was accompanied by neuromuscular disease. A PLN founder mutation (43 cases) and LMNA mutations (19 cases, 16 different mutations) were most prevalent and often demonstrated a specific phenotype. Other mutations were found in: MYH7, DES, TNNT2, DMD, TPM1, DMPK, SCN5A, SGCB (homozygous), and TNNI3. After a median follow-up of 40 months, the combined outcome of death from any cause, heart transplantation, or malignant ventricular arrhythmias in patients with a mutation was worse than in those without an identified mutation (hazard ratio 2.0, 95% confidence interval 1.4-3.0). This seems to be mainly attributable to a high prevalence of malignant ventricular arrhythmias and end-stage heart failure in LMNA and PLN mutation carriers. The yield of identified mutations in DCM index patients with clinical clues, such as associated neuromuscular disease or familial occurrence, is higher compared with those without these clues. For sporadic DCM, specific clinical characteristics may be used to select cases for DNA analysis

Schwannomatosis is a rare hereditary cancer syndrome in which patients develop multiple non-vestibular schwannomas. The chromatin remodelling gene SMARCB1 (also known as INI1, hSNF5, and BAF47) has been identified as a schwannomatosis predisposing gene, being involved in a subset of sporadic and familial cases. Recent studies have shown that SMARCB1 may also be involved in the development of multiple meningiomas. Previously, we demonstrated that the SMARCB1 exon 2 missense mutation c.143 C > T segregates with the presence of meningiomas in five members of a large family with multiple meningiomas and schwannomas. We extended our genetic analyses by screening 44 additional at-risk family members and identified 13 new carriers. Eleven of these were subjected to magnetic resonance imaging (MRI) of brain and spine. In addition, we analyzed four meningiomas and two schwannomas from family members for the presence of schwannomatosis-specific changes. We found in each tumor retention of the SMARCB1 exon 2 mutation, acquisition of an independent neurofibromatosis type 2 (NF2) gene mutation, and loss of heterozygosity at SMARCB1 and NF2 by loss of the wild-type copy of both genes. The MRI scans revealed one or more falx meningiomas in seven of 11 (64%) newly identified SMARCB1 mutation carriers. We conclude that the SMARCB1 exon 2 missense mutation in this family predisposes to the development of meningiomas as well as schwannomas, occurring via the same genetic pathways, and that this mutation preferentially induces cranial meningiomas located at the falx cerebri.

Aims: Crypts can be found with cardiovascular magnetic resonance imaging (CMR) in hypertrophic cardiomyopathy (HCM) mutation carriers without hypertrophy (carriers) using a modified two-chamber view through the inferoseptum, but also in other patients and healthy individuals with standard long-axis views. Since it is currently unknown if carriers display a specific crypt morphology, we compared crypts in carriers with other cardiac pathologies (controls). Besides, we aimed to determine the optimal imaging plane for the detection of crypts by comparing modified two-chamber views with standard long-axis views. Finally, we evaluated the accuracy of crypts to identify carriers in HCM family screening. Methods and results: Standard CMR long-axis views with additional modified two-chamber views were prospectively performed in carriers (n = 43), consecutive CMR control patients (n = 252), and mutation-negative family members (n = 15). Crypts were found in 70% (30/43) of carriers and in 12% (31/252) of controls (P < 0.001). Crypts in carriers showed deeper penetrance into the myocardium compared with controls (74 ± 21% vs. 59 ± 22%, P < 0.01). Detection of two or more crypts had a sensitivity of 51% and specificity of 94% for carriership. Modified two-chamber views doubled the sensitivity to detect crypts compared with standard long-axis views. In family screening, ≥2 crypts had a 100% positive predictive value to identify carriers. Conclusions: Multiple crypts in the absence of left ventricular hypertrophy are highly specific for HCM mutation carriership and warrant clinical follow-up. A modified two-chamber view has a superior sensitivity compared with standard long-axis views for crypt detection. CMR may be of additional value to identify carriers in family screening. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2012.

Aims Next to left ventricular (LV) hypertrophy, hypertrophic cardiomyopathy (HCM) is characterized by microvascular dysfunction and reduced myocardial external efficiency (MEE). Insights into the presence of these abnormalities as early markers of disease are of clinical importance in risk stratification, and development of therapeutic approaches. Therefore, the aim was to investigate myocardial perfusion and energetics in genotype-positive, phenotype-negative HCM subjects (carriers). Methods and results Fifteen carriers of an MYBPC3 mutation underwent [15O]water positron emission tomography (PET) to assess myocardial blood flow (MBF). [11C]acetate PET was performed to obtain myocardial oxygen consumption (MVO2). By use of cardiovascular magnetic resonance imaging, LV volumes and mass were defined to calculate MEE, i.e. the ratio between external work and MVO2. Eleven healthy, genotype-negative, family relatives underwent similar scanning protocols to serve as a control group. Left ventricular mass was comparable between carriers and controls (93 ± 25 vs. 99 ± 21 g, P= 0.85), as was MBF at rest (1.19 ± 0.34 vs. 1.18 ± 0.32 mL min−1 g−1, P= 0.92), and during hyperaemia (3.87 ± 0.75 vs. 3.96 ± 0.86 mL min−1 g−1, P= 0.77). Myocardial oxygen consumption averaged 0.137 ± 0.057 mL min−1 g−1 in carriers and was not significantly different from controls (0.125 ± 0.043 mL min−1 g−1, P= 0.29). Cardiac work, however, was slightly reduced in carriers (7398 ± 1384 vs. 9139 ± 2484 mmHg mL in controls, P= 0.08). As a consequence, MEE was significantly decreased in carriers (27 ± 10 vs. 36 ± 8% in controls, P= 0.02). Conclusion Carriers display reduced myocardial work generation in relation to oxygen consumption, in the absence of hypertrophy and flow abnormalities. Hence, impaired myocardial energetics may constitute a primary component of HCM pathogenesis.

In this part of a series on cardiogenetic founder mutations in the Netherlands, we review the Dutch founder mutations in hypertrophic cardiomyopathy (HCM) patients. HCM is a common autosomal dominant genetic disease affecting at least one in 500 persons in the general population. Worldwide, most mutations in HCM patients are identified in genes encoding sarcomeric proteins, mainly in the myosin-binding protein C gene (MYBPC3, OMIM #600958) and the beta myosin heavy chain gene (MYH7, OMIM #160760). In the Netherlands, the great majority of mutations occur in the MYBPC3, involving mainly three Dutch founder mutations in the MYBPC3 gene, the c.2373_2374insG, the c.2864_2865delCT and the c.2827C>T mutation. In this review, we describe the genetics of HCM, the genotype-phenotype relation of Dutch founder MYBPC3 gene mutations, the prevalence and the geographic distribution of the Dutch founder mutations, and the consequences for genetic counselling and testing. (Neth Heart J 2010;18:248-54.)

Hypertrophic cardiomyopathy (HCM) is a common hereditary heart disease associated with sudden cardiac death. predictive genetic counseling and testing are performed using adapted Huntington guidelines, that is, psychosocial care and time for reflection are not obligatory and the test result can be disclosed by telephone or mail. Proven mutation carriers detected by predictive DNA testing are advised to undergo regular cardiac follow-up according to international guidelines. We evaluated the opinion of 143 predictively tested HCM mutation carriers on received cardiogenetic care using questionnaires (response rate 86%). Predictive genetic counseling and DNA testing were evaluated on four domains: information provision, satisfaction with counseling, social pressure in DNA testing and regret of DNA testing. Opinions on cardiac follow-up were assessed pertaining to communication, nervous anticipation, reassurance, and general disadvantages. Genetic counseling was valued positively and only four carriers would rather not have known that they were a mutation carrier. A majority received their DNA test result by mail or telephone, and almost all were satisfied. Only 76% of carriers received regular cardiac follow-up. Those who did, had a positive attitude regarding the cardiac visits. General disadvantages of the visits were valued as low, especially by older carriers, men and carriers with manifest HCM. We conclude that our adapted Huntington guidelines are well accepted and that cardiogenetic care is generally appreciated by predictively tested HCM mutation carriers. To better understand the cause of the substantial portion of mutation carriers not receiving regular cardiac follow-up, although recommended in international guidelines, further research is needed. (C) 2009 Wiley-Liss, Inc

Idiopathic Ventricular Fibrillation (IVF) is defined as spontaneous VF without any known structural or electrical heart disease. A family history is present in up to 20% of probands with the disorder, suggesting that at least a subset of IVF is hereditary. A genome-wide haplotype-sharing analysis was performed for identification of the responsible gene in three distantly related families in which multiple individuals died suddenly or were successfully resuscitated at young age. We identified a haplotype, on chromosome 7q36, that was conserved in these three families and was also shared by 7 of 42 independent IVF patients. The shared chromosomal segment harbors part of the DPP6 gene, which encodes a putative component of the transient outward current in the heart. We demonstrated a 20-fold increase in DPP6 mRNA levels in the myocardium of carriers as compared to controls. Clinical evaluation of 84 risk-haplotype carriers and 71 noncarriers revealed no ECG or structural parameters indicative of cardiac disease. Penetrance of IVF was high; 50% of risk-haplotype carriers experienced (aborted) sudden cardiac death before the age of 58 years. We propose DPP6 as a gene for IVF and increased DPP6 expression as the likely pathogenetic mechanism.

Hypertrophic cardiomyopathy (HCM) is a common hereditary heart disease associated with heart failure and sudden death. Quality of life and psychological distress were found to be impaired in HCM patients but have never been assessed in mutation carriers, with or without manifest HCM. We aimed to assess quality of life and psychological distress, using standardized questionnaires, and to identify sociodemographic, clinical, risk and illness perception related predictors thereof in 228 HCM mutation carriers. HCM carriers' overall quality of life and distress scores did not differ from the Dutch population. Quality of life and distress were worst in carriers with manifest HCM before DNA testing and best in predictively tested carriers without HCM. The latter group had even significantly better quality of life than the general population. Substantial determinants of impaired physical quality of life were symptoms (beta = 5.2, P = 0.001) and stronger belief in serious consequences of carriership, (beta = 3.5, P

Background. Patients with hypertrophic cardiomyopathy (HCM) and HCM mutation carriers are at risk of sudden cardiac death (SCD). Both groups should therefore be subject to regular cardiological testing - including risk stratification for SCD - according to international guidelines. We evaluated Dutch cardiologists' knowledge of and adherence to international guidelines on risk stratification and prevention of SCD in mutation carriers with and without manifest HCM.Methods. A questionnaire was sent to 1109 Dutch cardiologists (in training) containing case-based questions.Results. The response rate was 21%. Own general knowledge on HCM care was rated as insufficient by 63% of cardiologists. The percentage of correct answers (i.e. in agreement with international guidelines), on the case-based questions ranged from 37 to 96%, being lowest in cases with an unknown number of risk factors for SCD. A substantial portion of correct answers was based on the correct answer 'ask an expert opinion'. Significantly more correct answers were provided in cases with manifest HCM. There was little difference between the answers of cardiologists with different self-reported levels of knowledge, with different numbers of HCM patients in their practice or with different numbers of carriers without manifest HCM.Conclusion. Knowledge on risk stratification and preventive therapy was mediocre, and knowledge gaps exist, especially on HCM mutation carriers without manifest disease. Fortunately, experts are frequently asked for their opinion which might bring patient care to an adequate level. Hopefully, our results will stimulate cardiologists to follow developments in this field, thereby increasing quality of care for HCM patients and mutation carriers. (Neth Heart J 2009;17:464-9.).

Hypertrophic cardiomyopathy is a common autosomal dominant disease, associated with heart failure and arrhythmias predisposing to sudden cardiac death. After the detection of the causal mutation in the proband predictive DNA testing of relatives is possible (cascade screening). Prevention of sudden cardiac death in patients with a high risk by means of an implantable cardioverter defibrillator is effective. In 97 hypertrophic cardiomyopathy families with a sarcomere gene mutation we retrospectively determined uptake of genetic counselling and predictive DNA testing in relatives within 1 year after the detection of the causal mutation in the proband. Uptake of genetic counselling was 39% and did not differ significantly by proband's or relative's gender, nor by young age of the relative (

The ESCAPE-HCM study is a prospective followup study of asymptomatic mutation-carrying relatives of HCM patients aiming at optimising anamnestic and cardiological evaluation and surveillance for this group. All relatives undergo regular cardiological evaluation and risk status is prospectively estimated, according to known HCM-related risk factors for sudden cardiac death. (Neth Heart J 2007;15:216-20.)

Prophylactic implantable cardioverter defibrillator (ICD) therapy prevents sudden cardiac death (SCD) among young adults with cardiogenetic conditions, but might reduce quality of life (QoL) due to potential device complications, ongoing medical appointments, and lifestyle restrictions. We investigated QoL in the first year after ICD implantation for the primary prevention of SCD and compared QoL scores with population norms.Consecutive patients with cardiogenetic conditions (aged 18-50 years) referred to the Academic Medical Center in Amsterdam to receive ICD therapy for the primary prevention of SCD between 2007 and 2009 were eligible. Patients completed questions about QoL (Short-Form 36 Health Survey; SF-36), depressive symptoms (Center for Epidemiologic Studies Depression scale; CES-D), anxiety (State-Trait Anxiety Inventory; STAI), and the impact of receiving ICD therapy on lifestyle and work, shortly before ICD implantation and after 2 months, 6 months, and 12 months.Thirty-five of 47 eligible patients participated. QoL was significantly reduced shortly before and 2 months after ICD implantation but improved over time and was comparable with population norms at 6 months and 12 months after ICD implantation. Yet, only about half of the patients believed they had a normal life like everyone else, and 28% had lost or changed their job due to their cardiogenetic condition and ICD therapy.Receiving a diagnosis of a cardiogenetic condition and subsequent ICD implantation was accompanied with a temporarily reduced QoL and a significant negative impact on professional life. Clinicians should inform their patients of the possible QoL consequences when deciding about ICD implantation in primary prevention of SCD in cardiogenetic conditions.

We present a family from a founder population referred for cardiogenetic evaluation for atrioventricular block in 3 siblings. Genetic testing, including whole-exome sequencing, did not identify a disease-causing mutation. After reconsidering the differential diagnosis, a nongenetic cause was identified. This case highlights the importance of a thorough clinical evaluation even when a genetic cause is seemingly obvious.