The clinical outcomes of noncompaction cardiomyopathy (NCCM) range from asymptomatic to heart failure, arrhythmias, and sudden cardiac death. Genetics play an important role in NCCM.
This study ...investigated the correlations among genetics, clinical features, and outcomes in adults and children diagnosed with NCCM.
A retrospective multicenter study from 4 cardiogenetic centers in the Netherlands classified 327 unrelated NCCM patients into 3 categories: 1) genetic, with a mutation in 32% (81 adults; 23 children) of patients; 2) probably genetic, familial cardiomyopathy without a mutation in 16% (45 adults; 8 children) of patients; or 3) sporadic, no family history, without mutation in 52% (149 adults; 21 children) of patients. Clinical features and major adverse cardiac events (MACE) during follow-up were compared across the children and adults.
MYH7, MYBPC3, and TTN mutations were the most common mutations (71%) found in genetic NCCM. The risk of having reduced left ventricular (LV) systolic dysfunction was higher for genetic patients compared with the probably genetic and sporadic cases (p = 0.024), with the highest risk in patients with multiple mutations and TTN mutations. Mutations were more frequent in children (p = 0.04) and were associated with MACE (p = 0.025). Adults were more likely to have sporadic NCCM. High risk for cardiac events in children and adults was related to LV systolic dysfunction in mutation carriers, but not in sporadic cases. Patients with MYH7 mutations had low risk for MACE (p = 0.03).
NCCM is a heterogeneous condition, and genetic stratification has a role in clinical care. Distinguishing genetic from nongenetic NCCM complements prediction of outcome and may lead to management and follow-up tailored to genetic status.
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ABSTRACT
Mutation detection through exome sequencing allows simultaneous analysis of all coding sequences of genes. However, it cannot yet replace Sanger sequencing (SS) in diagnostics because of ...incomplete representation and coverage of exons leading to missing clinically relevant mutations. Targeted next‐generation sequencing (NGS), in which a selected fraction of genes is sequenced, may circumvent these shortcomings. We aimed to determine whether the sensitivity and specificity of targeted NGS is equal to those of SS. We constructed a targeted enrichment kit that includes 48 genes associated with hereditary cardiomyopathies. In total, 84 individuals with cardiomyopathies were sequenced using 151 bp paired‐end reads on an Illumina MiSeq sequencer. The reproducibility was tested by repeating the entire procedure for five patients. The coverage of ≥30 reads per nucleotide, our major quality criterion, was 99% and in total ∼21,000 variants were identified. Confirmation with SS was performed for 168 variants (155 substitutions, 13 indels). All were confirmed, including a deletion of 18 bp and an insertion of 6 bp. The reproducibility was nearly 100%. We demonstrate that targeted NGS of a disease‐specific subset of genes is equal to the quality of SS and it can therefore be reliably implemented as a stand‐alone diagnostic test.
A NGS stand‐alone diagnostic test for hereditary cardio‐myopathies. Parallel analyses of 48 genes on a MiSeq identified ∼21,000 variants in 84 patients. The sensitivity and specificity of this test equals Sanger Sequencing. In total 168 variants were confirmed, no false‐positives or false‐negatives were detected.
We sought to determine the influence of genotype on clinical course and arrhythmic outcome among arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C)-associated mutation carriers.
...Pathogenic mutations in desmosomal and non-desmosomal genes were identified in 577 patients (241 families) from USA and Dutch ARVD/C cohorts. Patients with sudden cardiac death (SCD)/ventricular fibrillation (VF) at presentation (n = 36) were younger (median 23 vs. 36 years; P < 0.001) than those presenting with sustained monomorphic ventricular tachycardia (VT). Among 541 subjects presenting alive, over a mean follow-up of 6 ± 7 years, 12 (2%) patients died, 162 (30%) had sustained VT/VF, 78 (14%) manifested left ventricular dysfunction (EF < 55%), 28 (5%) experienced heart failure (HF), and 10 (2%) required cardiac transplantation. Patients (n = 22; 4%) with >1 mutation had significantly earlier occurrence of sustained VT/VF (mean age 28 ± 12 years), lower VT-/VF-free survival (P = 0.037), more frequent left ventricular dysfunction (29%), HF (19%) and cardiac transplantation (9%) when compared with those with only one mutation. Desmoplakin mutation carriers experienced more than four-fold occurrence of left ventricular dysfunction (40%) and HF (13%) than PKP2 carriers. Missense mutation carriers had similar death-/transplant-free survival and VT/VF penetrance (P = 0.137) when compared with those with truncating or splice site mutations. Men are more likely to be probands (P < 0.001), symptomatic (P < 0.001) and have earlier and more severe arrhythmic expression.
Presentation with SCD/VF occurs at a significantly younger age when compared with sustained monomorphic VT. The genotype of ARVD/C mutation carriers impacts clinical course and disease expression. Male sex negatively modifies phenotypic expression.
Abstract
Aims
This study aims to improve risk stratification for primary prevention implantable cardioverter defibrillator (ICD) implantation by developing a new mutation-specific prediction model ...for malignant ventricular arrhythmia (VA) in phospholamban (PLN) p.Arg14del mutation carriers. The proposed model is compared to an existing PLN risk model.
Methods and results
Data were collected from PLN p.Arg14del mutation carriers with no history of malignant VA at baseline, identified between 2009 and 2020. Malignant VA was defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. A prediction model was developed using Cox regression. The study cohort consisted of 679 PLN p.Arg14del mutation carriers, with a minority of index patients (17%) and male sex (43%), and a median age of 42 years interquartile range (IQR) 27–55. During a median follow-up of 4.3 years (IQR 1.7–7.4), 72 (10.6%) carriers experienced malignant VA. Significant predictors were left ventricular ejection fraction, premature ventricular contraction count/24 h, amount of negative T waves, and presence of low-voltage electrocardiogram. The multivariable model had an excellent discriminative ability {C-statistic 0.83 95% confidence interval (CI) 0.78–0.88}. Applying the existing PLN risk model to the complete cohort yielded a C-statistic of 0.68 (95% CI 0.61–0.75).
Conclusion
This new mutation-specific prediction model for individual VA risk in PLN p.Arg14del mutation carriers is superior to the existing PLN risk model, suggesting that risk prediction using mutation-specific phenotypic features can improve accuracy compared to a more generic approach.
Graphical Abstract
Malignant VA risk prediction in PLN p.Arg14del carriers. With the mutation specific risk factors low and high risk groups can be identified. PLN, Phospholamban; VA, Ventricular arrhythmia.
The Risk for Type B Aortic Dissection in Marfan Syndrome den Hartog, Alexander W., MD; Franken, Romy, MD; Zwinderman, Aeilko H., PhD ...
Journal of the American College of Cardiology,
01/2015, Letnik:
65, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Abstract Background Aortic dissections involving the descending aorta are a major clinical problem in patients with Marfan syndrome. Objectives The purpose of this study was to identify clinical ...parameters associated with type B aortic dissection and to develop a risk model to predict type B aortic dissection in patients with Marfan syndrome. Methods Patients with the diagnosis of Marfan syndrome and magnetic resonance imaging or computed tomographic imaging of the aorta were followed for a median of 6 years for the occurrence of type B dissection or the combined end point of type B aortic dissection, distal aortic surgery, and death. A model using various clinical parameters as well as genotyping was developed to predict the risk for type B dissection in patients with Marfan syndrome. Results Between 1998 and 2013, 54 type B aortic dissections occurred in 600 patients with Marfan syndrome (mean age 36 ± 14 years, 52% male). Independent variables associated with type B aortic dissection were prior prophylactic aortic surgery (hazard ratio: 2.1; 95% confidence interval: 1.2 to 3.8; p = 0.010) and a proximal descending aorta diameter ≥27 mm (hazard ratio: 2.2; 95% confidence interval: 1.1 to 4.3; p = 0.020). In the risk model, the 10-year occurrence of type B aortic dissection in low-, moderate-, and high-risk patients was 6%, 19%, and 34%, respectively. Angiotensin II receptor blocker therapy was associated with fewer type B aortic dissections (hazard ratio: 0.3; 95% confidence interval: 0.1 to 0.9; p = 0.030). Conclusions Patients with Marfan syndrome with prior prophylactic aortic surgery are at substantial risk for type B aortic dissection, even when the descending aorta is only slightly dilated. Angiotensin II receptor blocker therapy may be protective in the prevention of type B aortic dissections.
Aims
To investigate whether phospholamban gene (PLN) mutations underlie patients diagnosed with either arrhythmogenic right ventricular cardiomyopathy (ARVC) or idiopathic dilated cardiomyopathy ...(DCM).
Methods and results
We screened a cohort of 97 ARVC and 257 DCM unrelated index patients for PLN mutations and evaluated their clinical characteristics. PLN mutation R14del was identified in 12 (12 %) ARVC patients and in 39 (15 %) DCM patients. Haplotype analysis revealed a common founder, estimated to be between 575 and 825 years old. A low voltage electrocardiogram was present in 46 % of R14del carriers. Compared with R14del– DCM patients, R14del+ DCM patients more often demonstrated appropriate implantable cardioverter defibrillator discharge (47 % vs. 10 %, P < 0.001), cardiac transplantation (18 % vs. 2 %, P < 0.001), and a family history for sudden cardiac death (SCD) at < 50 years (36 % vs. 16 %, P = 0.007). We observed a similar pattern in the ARVC patients although this was not statistically significant. The average age of 26 family members who died of SCD was 37.7 years. Immunohistochemistry in available myocardial samples revealed absent/depressed plakoglobin levels at intercalated disks in five of seven (71 %) R14del+ ARVC samples, but in only one of nine (11 %) R14del+ DCM samples (P = 0.03).
Conclusions
The PLN R14del founder mutation is present in a substantial number of patients clinically diagnosed with DCM or ARVC. R14del+ patients diagnosed with DCM showed an arrhythmogenic phenotype, and SCD at young age can be the presenting symptom. These findings support the concept of ‘arrhythmogenic cardiomyopathy’.
Patients with Marfan syndrome have an increased risk of life-threatening aortic complications, mostly preceded by aortic dilatation. Treatment with losartan, an angiotensin-II receptor-1 blocker, may ...reduce aortic dilatation rate in Marfan patients.
In this multicentre, open-label, randomized controlled trial with blinded assessments, we compared losartan treatment with no additional treatment in operated and unoperated adults with Marfan syndrome. The primary endpoint was aortic dilatation rate at any predefined aortic level after 3 years of follow-up, as determined by magnetic resonance imaging. A total of 233 participants (47% female) underwent randomization to either losartan (n = 116) or no additional treatment (n = 117). Aortic root dilatation rate after 3.1 ± 0.4 years of follow-up was significantly lower in the losartan group than in controls (0.77 ± 1.36 vs. 1.35 ± 1.55 mm, P = 0.014). Aortic dilatation rate in the trajectory beyond the aortic root was not significantly reduced by losartan. In patients with prior aortic root replacement, aortic arch dilatation rate was significantly lower in the losartan group when compared with the control group (0.50 ± 1.26 vs. 1.01 ± 1.31 mm, P = 0.033). No significant differences in separate clinical endpoints or the composite endpoint (aortic dissection, elective aortic surgery, cardiovascular death) between the groups could be demonstrated.
In adult Marfan patients, losartan treatment reduces aortic root dilatation rate. After aortic root replacement, losartan treatment reduces dilatation rate of the aortic arch.
Recent advancements in next generation sequencing (NGS) technology have led to the identification of the giant sarcomere gene, titin (TTN), as a major human disease gene. Truncating variants of TTN ...(TTNtv) especially in the A-band region account for 20% of dilated cardiomyopathy (DCM) cases. Much attention has been focused on assessment and interpretation of TTNtv in human disease; however, missense and non-frameshifting insertions/deletions (NFS-INDELs) are difficult to assess and interpret in clinical diagnostic workflow. Targeted sequencing covering all exons of TTN was performed on a cohort of 530 primary DCM patients from three cardiogenetic centres across Europe. Using stringent bioinformatic filtering, twenty-nine and two rare TTN missense and NFS-INDELs variants predicted deleterious were identified in 6.98% and 0.38% of DCM patients, respectively. However, when compared with those identified in the largest available reference population database, no significant enrichment of such variants was identified in DCM patients. Moreover, DCM patients and reference individuals had comparable frequencies of splice-region missense variants with predicted splicing alteration. DCM patients and reference populations had comparable frequencies of rare predicted deleterious TTN missense variants including splice-region missense variants suggesting that these variants are not independently causative for DCM. Hence, these variants should be classified as likely benign in the clinical diagnostic workflow, although a modifier effect cannot be excluded at this stage.
KBTBD13 is a novel cardiomyopathy gene Winter, Josine M.; Bouman, Karlijn; Strom, Joshua ...
Human mutation,
December 2022, Letnik:
43, Številka:
12
Journal Article
Recenzirano
Odprti dostop
KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.Arg408Cys (KBTBD13 p.R408C). Although KBTBD13 is expressed in ...cardiac muscle, cardiac involvement in NEM6 is unknown. Here, we constructed pedigrees of three families with the KBTBD13 p.R408C variant. In 65 evaluated patients, 12% presented with left ventricle dilatation, 29% with left ventricular ejection fraction< 50%, 8% with atrial fibrillation, 9% with ventricular tachycardia, and 20% with repolarization abnormalities. Five patients received an implantable cardioverter defibrillator, three cases of sudden cardiac death were reported. Linkage analysis confirmed cosegregation of the KBTBD13 p.R408C variant with the cardiac phenotype. Mouse studies revealed that (1) mice harboring the Kbtbd13 p.R408C variant display mild diastolic dysfunction; (2) Kbtbd13‐deficient mice have systolic dysfunction. Hence, (1) KBTBD13 is associated with cardiac dysfunction and cardiomyopathy; (2) KBTBD13 should be added to the cardiomyopathy gene panel; (3) NEM6 patients should be referred to the cardiologist.
Genetic variants in gene-encoding proteins involved in cell−cell connecting structures, such as desmosomes and gap junctions, may cause a skin and/or cardiac phenotype, of which the combination is ...called cardiocutaneous syndrome. The cardiac phenotype is characterized by cardiomyopathy and/or arrhythmias, while the skin particularly displays phenotypes such as keratoderma, hair abnormalities and skin fragility. The reported variants associated with cardiocutaneous syndrome, in genes DSP, JUP, DSC2, KLHL24, GJA1, are classified by interpretation guidelines from the American College of Medical Genetics and Genomics. The genotype−phenotype correlation, however, remains poorly understood. By providing an overview of variants that are assessed for a functional protein pathology, we show that this number (n = 115) is low compared to the number of variants that are assessed by in silico algorithms (>5000). As expected, there is a mismatch between the prediction of variant pathogenicity and the prediction of the functional effect compared to the real functional evidence. Aiding to improve genotype−phenotype correlations, we separate variants into ‘protein reducing’ or ‘altered protein’ variants and provide general conclusions about the skin and heart phenotype involved. We conclude by stipulating that adequate prognoses can only be given, and targeted therapies can only be designed, upon full knowledge of the protein pathology through functional investigation.
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