Publications (152)865.82 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: The genetic evaluation of dilated cardiomyopathy (DCM) has been challenging, owing in large part to marked genetic heterogeneity. However, lower costs from next-generation sequencing have enabled gene discovery and the expansion of genetic testing panels. These advances have improved molecular diagnostics and predictive testing in DCM. We provide a rationale and recommendation for clinical genetic testing in all DCM cases.
- [Show abstract] [Hide abstract] ABSTRACT: The presentation, natural history, clinical outcomes, and response to therapy in patients with heart failure differ in some ways across populations. Women, older adults, and non-Caucasian racial or ethnic groups comprise a substantial proportion of the overall heart failure population, but they have typically been underrepresented in clinical trials. As a result, uncertainty exists about the efficacy of some guideline-directed medical therapies and devices in specific populations, which may result in the under or over treatment of these patients. Even when guideline-based treatments are prescribed, socioeconomic, physical, or psychological factors may impact non-Caucasian and older adult patient groups to a different extent and impact the application, effectiveness, and tolerability of these therapies. Individualized therapy based on tailored biology (genetics, proteomics, metabolomics), socioeconomic and cultural considerations, and individual goals and preferences may be the optimal approach for managing diverse patients. This comprehensive approach to personalized medicine is evolving, but in the interim, the scientific community should continue focused efforts on intensifying research in special populations, prescribing guideline directed medical therapy unless contraindicated, and implementing evidence-based strategies including patient education and multidisciplinary teams in the management of patients. Copyright © 2015 Elsevier Inc. All rights reserved.
- [Show abstract] [Hide abstract] ABSTRACT: We propose that Stage D advanced heart failure be defined as the presence of progressive and/or persistent severe signs and symptoms of heart failure despite optimized medical, surgical, and device therapy. Importantly, the progressive decline should be primarily driven by the heart failure syndrome. Formally defining advanced heart failure and specifying when medical and device therapies have failed is challenging, but signs and symptoms, hemodynamics, exercise testing, biomarkers, and risk prediction models are useful in this process. Identification of patients in Stage D is a clinically important task since treatments are inherently limited, morbidity is typically progressive, and survival is often short. Age, frailty, and psychosocial issues impact both outcomes and selection of therapy for Stage D patients. Heart transplant and mechanical circulatory support devices are potential treatment options in select patients. In addition to considering indications, contraindications, clinical status, and comorbidities, treatment selection for Stage D patients involves incorporating the patient's wishes for survival versus quality of life and palliative and hospice care should be integrated into care plans. More research is needed to determine optimal strategies for patient selection and medical decision making, with the ultimate goal of improving clinical and patient centered outcomes in patients with Stage D heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.
- [Show abstract] [Hide abstract] ABSTRACT: Depressed sarcoplasmic reticulum (SR) Ca(2+) cycling, a universal characteristic of human and experimental heart failure, may be associated with genetic alterations in key Ca(2+)-handling proteins. In this study, we identified a novel PLN mutation (R25C) in dilated cardiomyopathy (DCM) and investigated its functional significance in cardiomyocyte Ca(2+)-handling and contractility. Exome sequencing identified a C73T substitution in the coding region of PLN in a family with DCM. The 4 heterozygous family members had implantable cardiac defibrillators, and 3 developed prominent ventricular arrhythmias. Overexpression of R25C-PLN in adult rat cardiomyocytes significantly suppressed the Ca(2+) affinity of SR Ca(2+)-ATPase (SERCA2a), resulting in decreased SR Ca(2+) content, Ca(2+) transients and impaired contractile function, compared to WT-PLN. These inhibitory effects were associated with enhanced interaction of R25C-PLN with SERCA2, which was prevented by PKA phosphorylation. Accordingly, isoproterenol stimulation relieved the depressive effects of R25C-PLN in cardiomyocytes. However, R25C-PLN also elicited increases in the frequency of Ca(2+) sparks and waves as well as stress-induced aftercontractions. This was accompanied by increased Ca(2+)/calmodulin-dependent protein kinase II activity and hyper-phosphorylation of RyR2 at serine 2814. The findings demonstrate that human R25C-PLN is associated with super-inhibition of SERCA2a and Ca(2+) transport as well as increased SR Ca(2+) leak, promoting arrhythmogenesis under stress conditions. This is the first mechanistic evidence that increased PLN inhibition may impact both SR Ca(2+) uptake and Ca(2+) release activities and suggests that the human R25C-PLN may be a prognostic factor for increased ventricular arrhythmia risk in DCM carriers. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: email@example.com.
- [Show abstract] [Hide abstract] ABSTRACT: Dilated Cardiomyopathy (DCM) is a disease of the myocardium characterized by left ventricular dilatation and diminished contractile function. In this report we describe a novel DCM mutation identified for the first time in the myosin regulatory light chain (RLC), replacing Aspartic Acid at position 94 with Alanine (D94A). The mutation was identified by exome sequencing of three adult first-degree relatives who met formal criteria for idiopathic DCM. To gain insight into the functional significance of this pathogenic MYL2 variant, we have cloned and purified the human ventricular RLC wild-type (WT) and D94A-mutant proteins and performed in vitro experiments using RLC-exchanged porcine cardiac preparations. The mutation was observed to induce a reduction in the α-helical content of the RLC and imposed intra-molecular rearrangements. The Ca(2+) -calmodulin-activated myosin light chain kinase phosphorylation of RLC was not affected by D94A. The mutation was seen to impair the binding of RLC to the MHC (myosin heavy chain), and its incorporation into the RLC-depleted porcine myosin. The actin-activated ATPase activity of mutant-reconstituted porcine cardiac myosin was significantly higher compared to ATPase of WT. No changes in myofibrillar ATPase-pCa relationship were observed in WT- or D94A-reconstituted preparations. Measurements of contractile force showed a slightly reduced maximal tension per cross-section of muscle with no change in calcium sensitivity of force in D94A-reconstituted skinned porcine papillary muscle strips compared with WT. Our data indicate that subtle structural rearrangements in the RLC molecule followed by its impaired interaction with the MHC may trigger functional abnormalities contributing to the DCM phenotype. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
- [Show abstract] [Hide abstract] ABSTRACT: We describe the development and implementation of a randomized controlled trial to investigate the impact of genomic counseling on a cohort of patients with heart failure (HF) or hypertension (HTN), managed at a large academic medical center, the Ohio State University Wexner Medical Center (OSUWMC). Our study is built upon the existing Coriell Personalized Medicine Collaborative (CPMC®). OSUWMC patient participants with chronic disease (CD) receive eight actionable complex disease and one pharmacogenomic test report through the CPMC® web portal. Participants are randomized to either the in-person post-test genomic counseling—active arm, versus web-based only return of results—control arm. Study-specific surveys measure: (1) change in risk perception; (2) knowledge retention; (3) perceived personal control; (4) health behavior change; and, for the active arm (5), overall satisfaction with genomic counseling. This ongoing partnership has spurred creation of both infrastructure and procedures necessary for the implementation of genomics and genomic counseling in clinical care and clinical research. This included creation of a comprehensive informed consent document and processes for prospective return of actionable results for multiple complex diseases and pharmacogenomics (PGx) through a web portal, and integration of genomic data files and clinical decision support into an EPIC-based electronic medical record. We present this partnership, the infrastructure, genomic counseling approach, and the challenges that arose in the design and conduct of this ongoing trial to inform subsequent collaborative efforts and best genomic counseling practices.
- [Show abstract] [Hide abstract] ABSTRACT: Remarkable progress has been made in understanding the genetic basis of dilated cardiomyopathy (DCM). Rare variants in >30 genes, some also involved in other cardiomyopathies, muscular dystrophy, or syndromic disease, perturb a diverse set of important myocardial proteins to produce a final DCM phenotype. Large, publicly available datasets have provided the opportunity to evaluate previously identified DCM-causing mutations, and to examine the population frequency of sequence variants similar to those that have been observed to cause DCM. The frequency of these variants, whether associated with dilated or hypertrophic cardiomyopathy, is greater than estimates of disease prevalence. This mismatch might be explained by one or more of the following possibilities: that the penetrance of DCM-causing mutations is lower than previously thought, that some variants are noncausal, that DCM prevalence is higher than previously estimated, or that other more-complex genomics underlie DCM. Reassessment of our assumptions about the complexity of the genomic and phenomic architecture of DCM is warranted. Much about the genomic basis of DCM remains to be investigated, which will require comprehensive genomic studies in much larger cohorts of rigorously phenotyped probands and family members than previously examined.
- [Show abstract] [Hide abstract] ABSTRACT: Recent advances have expanded our ability to conduct a comprehensive genetic evaluation for dilated cardiomyopathy (DCM). By evaluating recent literature, this review aims to bring the reader up-to-date on the genetic evaluation of DCM. Updated guidelines have been published. Mutations in BAG3, including a large deletion, were identified in 2 % of DCM. Truncating mutations in TTN were reported in 25 % of DCM. Two new genes have been reported with autosomal recessive DCM. These studies illustrate the role of improved technologies while raising the possibility of a complex genetic model for DCM. The inclusion of TTN has led to an increased genetic testing detection rate of 40 %. While our ability to identify disease-causing variants has increased, so has the identification of variants of unknown significance. A genetic evaluation for DCM must therefore address this complexity.
- [Show abstract] [Hide abstract] ABSTRACT: The value of family history (FH) is well established, but its sensitivity to detect familial dilated cardiomyopathy (FDC) has been infrequently examined. A genetic ancillary study was created as a component of the HF-ACTION trial, a multicenter, prospective, randomized clinical trial of exercise in patients with heart failure and an ejection fraction <35%. A FH-based study using a structured questionnaire mailed to all consenting individuals was incorporated into the genetic ancillary. FH responses were analyzed for dilated cardiomyopathy (DCM) in family members. Of the 741 individuals with data available, 358 (48.3%) had nonischemic and 383 (51.6%) had ischemic etiology, and of these 164 (45.8%) and 201 (52.4%), respectively, returned evaluable questionnaires. Of those with nonischemic etiology, 14/164 (8.5%) reported at least one first-degree family member with DCM or an enlarged heart; another 21/164 (12.8%) reported a FH of "cardiomyopathy," a less specific term to indicate DCM. At least 8.5% of patients with nonischemic etiology in the HF-ACTION genetic ancillary study provided FH indicating familial DCM, information important to inform further genetic analyses of this cohort and to plan other studies.
- [Show abstract] [Hide abstract] ABSTRACT: Acute decompensated heart failure (ADHF) is a complex clinical event associated with excess morbidity and mortality. Managing ADHF patients is challenging because of the lack of effective treatments that both reduce symptoms and improve clinical outcomes. Existing guideline recommendations are largely based on expert opinion, but several recently published trials have yielded important data to inform both current clinical practice and future research directions. New insight has been gained regarding volume management, including dosing strategies for intravenous loop diuretics and the role of ultrafiltration in patients with heart failure and renal dysfunction. Although the largest ADHF trial to date (ASCEND-HF, using nesiritide) was neutral, promising results with other investigational agents have been reported. If these findings are confirmed in phase III trials, novel compounds, such as relaxin, omecamtiv mecarbil, and ularitide, among others, may become therapeutic options. Translation of research findings into quality clinical care can not be overemphasized. Although many gaps in knowledge exist, ongoing studies will address issues around delivery of evidence-based care to achieve the goal of improving the health status and clinical outcomes of patients with ADHF.
- [Show abstract] [Hide abstract] ABSTRACT: The number of clinically available genetic tests for heritable cardiovascular diseases has recently increased because of novel gene discoveries and advancements in DNA sequencing technologies. The purpose of this review is to provide up-to-date genetic testing information and guidance on how to incorporate genetic testing into cardiovascular medicine. Heritable cardiovascular conditions display vast genetic heterogeneity, genetic overlap between phenotypes, incomplete penetrance and variable expressivity, and are associated with risk for sudden cardiac death, making the practice of cardiovascular genetic medicine a great responsibility. Multigene testing panels now exist for many cardiovascular conditions, and test utility has recently been augmented by population-based genomic sequence datasets. Large amounts of DNA sequence data necessitate rigorous interpretation of this probabilistic information. Timely practice guidelines and expert statements have been published. To fully realize the benefits of clinical genetic testing in cardiovascular medicine, clinicians must implement several components including judicious genetic testing, pretest and posttest genetic counseling, interpretation and application of genetic test results, and cascade family genetic testing and clinical screening. Components important to the proper integration of cardiovascular genetic medicine are offered.
- [Show abstract] [Hide abstract] ABSTRACT: LMNA cardiomyopathy presents with electrocardiogram (ECG) abnormalities, conduction system disease (CSD), and/or arrhythmias before the onset of dilated cardiomyopathy (DCM). Knowing the time interval between the onset of CSD and its progression to DCM would help to guide clinical care. We evaluated family members from 16 pedigrees previously identified to carry LMNA mutations for the ages of onset of ECG abnormalities, CSD, or arrhythmia and of left ventricular enlargement (LVE) and/or systolic dysfunction. Of 103 subjects, 64 carried their family LMNA mutation, and 51 (79%) had ECG abnormalities with a mean age of onset of 41.2 years (range 18-76). Ventricular dysfunction was observed in 26 with a mean age of onset of 47.6 years (range 28-82); at diagnosis 9 had systolic dysfunction but no LVE, 5 had LVE but no systolic dysfunction, and 11 had DCM. Of 16 subjects identified with ECG abnormalities who later developed ventricular dysfunction, the median ages of onset by log-rank analyses were 41 and 48 years, respectively. ECG abnormalities preceded DCM with a median difference of 7 years. Clinical surveillance should occur at least annually in those at risk for LMNA cardiomyopathy with any ECG findings.
- [Show abstract] [Hide abstract] ABSTRACT: BACKGROUND: -Familial dilated cardiomyopathy is a genetically heterogeneous disease with >30 known genes. TTN truncating variants were recently implicated in a candidate gene study to cause 25% of familial and 18% of sporadic dilated cardiomyopathy (DCM) cases. METHODS AND RESULTS: -We used an unbiased genome-wide approach employing both linkage analysis and variant filtering across the exome sequences of 48 individuals affected with DCM from 17 families to identify genetic cause. Linkage analysis ranked the TTN region as falling under the second highest genome-wide multipoint linkage peak, MLOD 1.59. We identified six TTN truncating variants carried by affected with DCM in 7 of 17 DCM families (LOD 2.99); 2 of these 7 families also had novel missense variants segregated with disease. Two additional novel truncating TTN variants did not segregate with DCM. Nucleotide diversity at the TTN locus, including missense variants, was comparable to five other known DCM genes. The average number of missense variants in the exome sequences from the DCM cases or the ~5,400 cases from the Exome Sequencing Project was ~23 per individual. The average number of TTN truncating variants in the Exome Sequencing Project was 0.014 per individual. We also identified a region (chr9q21.11-q22.31) with no known DCM genes with a maximum heterogeneity LOD score of 1.74. CONCLUSIONS: -These data suggest that TTN truncating variants contribute to DCM cause. However, the lack of segregation of all identified TTN truncating variants illustrates the challenge of determining variant pathogenicity even with full exome sequencing.
- [Show abstract] [Hide abstract] ABSTRACT: The goal of the Familial Dilated Cardiomyopathy (FDC) Research Project, initiated in 1993, has been to identify and characterize FDC genetic cause. All participating individuals have been consented for the return of genetic results, an important but challenging undertaking. Since the inception of the Project we have enrolled 606 probands, and 269 of these had 1670 family members also enrolled. Each subject was evaluated for idiopathic dilated cardiomyopathy (IDC) and pedigrees were categorized as familial or sporadic. The coding regions of 14 genes were resequenced in 311 to 324 probands in five studies. Ninety-two probands were found to carry nonsynonymous rare variants absent in controls, and with Clinical Laboratory Improvement Amendment of 1988 (CLIA) compliant protocols, relevant genetic results were returned to these probands and their consented relatives by study genetic counselors and physicians in 353 letters. In 10 of the 51 families that received results >1 year ago, at least 23 individuals underwent CLIA confirmation testing for their family's rare variant. Return of genetic results has been successfully undertaken in the FDC Research Project. This report describes the methods utilized in the process of returning research results. We use this information as a springboard for providing guidance to other genetic research groups and proposing future directions in this arena.
- [Show abstract] [Hide abstract] ABSTRACT: This review provides the rationale for integrating genomic and protein biomarkers in the evolving diagnosis and management of dilated cardiomyopathy (DCM) and its causal pathway to heart failure (HF), with a larger objective to serve as a template for genomic and phenomic profiling of other cardiovascular disease. DCM is a major cause of HF and accounts for more than half of heart transplantation in adults and children worldwide. DCM may remain asymptomatic for years, but HF and/or arrhythmias, both late manifestations of the disease, ultimately cause significant morbidity and mortality. A significant proportion of DCM has a genetic etiology. DCM can also result from environmental injury such as infection, toxins, or catecholamine excess. While molecular genetic testing can identify those at risk for genetic DCM, epigenetic and sentinel phenomic staging can help to identify those at highest risk in need for intervention. Phenomic staging includes integrating clinical and imaging features, transcriptomics, higher order proteomics and metabolomics interactions, and epidemiological data. This principle can be applied in family members of patients with DCM, where genetic testing and clinical phenotyping are indicated. This will allow the design of specific interventions tailored to individuals sharing similar risks, to alter the natural history of DCM and obviate complications such as HF/arrhythmias.
- [Show abstract] [Hide abstract] ABSTRACT: Aldosterone antagonists (or mineralocorticoid receptor antagonists [MRAs]) are guideline-recommended therapy for patients with moderate to severe heart failure (HF) symptoms and reduced left ventricular ejection fraction (LVEF), and in postmyocardial infarction patients with HF. The Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF) trial evaluated the MRA eplerenone in patients with mild HF symptoms. Eplerenone reduced the risk of the primary endpoint of cardiovascular death or HF hospitalization (hazard ratio [HR] 0.63, 95% confidence interval [CI] 0.54-0.74, P < .001) and all-cause mortality (adjusted HR 0.76, 95% CI 0.62-0.93, P < .008) after a median of 21 months. Based on EMPHASIS-HF, an MRA is recommended for patients with New York Heart Association (NYHA) Class II-IV symptoms and reduced LVEF (<35%) on standard therapy (Strength of Evidence A). Patients with NYHA Class II symptoms should have another high-risk feature to be consistent with the EMPHASIS-HF population (age >55 years, QRS duration >130 msec [if LVEF between 31% and 35%], HF hospitalization within 6 months or elevated B-type natriuretic peptide level). Renal function and serum potassium should be closely monitored. Dose selection should consider renal function, baseline potassium, and concomitant drug interactions. The efficacy of eplerenone in patients with mild HF symptoms translates into a unique opportunity to reduce morbidity and mortality earlier in the course of the disease.
- [Show abstract] [Hide abstract] ABSTRACT: This review examines the application of next-generation sequencing (NGS) technologies in the identification of the causation of nonsyndromic genetic cardiomyopathies. NGS sequencing of the entire genetic coding sequence (the exome) has successfully identified five novel genes and causative variants for cardiomyopathies without previously known cause within the last 12 months. Continual rapidly decreasing costs of NGS will shortly allow cost-effective sequencing of the entire genomes of affected individuals and their relatives to include noncoding and regulatory variant discovery and epigenetic profiling. Despite this rapid technological progress with sequencing, analysis of these large data sets remains challenging, particularly for assigning causality to novel rare variants identified in DNA samples from patients with cardiomyopathy. NGS technologies are rapidly moving to identify novel rare variants in patients with cardiomyopathy, but assigning pathogenicity to these novel variants remains challenging.
- [Show abstract] [Hide abstract] ABSTRACT: Association tests that pool minor alleles into a measure of burden at a locus have been proposed for case-control studies using sequence data containing rare variants. However, such pooling tests are not robust to the inclusion of neutral and protective variants, which can mask the association signal from risk variants. Early studies proposing pooling tests dismissed methods for locus-wide inference using nonnegative single-variant test statistics based on unrealistic comparisons. However, such methods are robust to the inclusion of neutral and protective variants and therefore may be more useful than previously appreciated. In fact, some recently proposed methods derived within different frameworks are equivalent to performing inference on weighted sums of squared single-variant score statistics. In this study, we compared two existing methods for locus-wide inference using nonnegative single-variant test statistics to two widely cited pooling tests under more realistic conditions. We established analytic results for a simple model with one rare risk and one rare neutral variant, which demonstrated that pooling tests were less powerful than even Bonferroni-corrected single-variant tests in most realistic situations. We also performed simulations using variants with realistic minor allele frequency and linkage disequilibrium spectra, disease models with multiple rare risk variants and extensive neutral variation, and varying rates of missing genotypes. In all scenarios considered, existing methods using nonnegative single-variant test statistics had power comparable to or greater than two widely cited pooling tests. Moreover, in disease models with only rare risk variants, an existing method based on the maximum single-variant Cochran-Armitage trend chi-square statistic in the locus had power comparable to or greater than another existing method closely related to some recently proposed methods. We conclude that efficient locus-wide inference using single-variant test statistics should be reconsidered as a useful framework for devising powerful association tests in sequence data with rare variants.
University of PittsburghPittsburgh, Pennsylvania, United States
Oregon Health and Science University
Portland, OR, United States
- Department of Medicine
University of Utah
Salt Lake City, Utah, United States
- Division of Cardiology