Common- and rare-variant genetic architecture of heart failure across the allele frequency spectrum.

Heart failure (HF) is a complex trait, influenced by environmental and genetic factors, that affects over 30 million individuals worldwide. Historically, the genetics of HF have been studied in Mendelian forms of disease, where rare genetic variants have been linked to familial cardiomyopathies. More recently, genome-wide association studies (GWAS) have successfully identified common genetic variants associated with risk of HF. However, the relative importance of genetic variants across the allele-frequency spectrum remains incompletely characterized. Here, we report the results of common- and rare-variant association studies of all-cause heart failure, applying recently developed methods to quantify the heritability of HF attributable to different classes of genetic variation. We combine GWAS data across multiple populations including 207,346 individuals with HF and 2,151,210 without, identifying 176 risk loci at genome-wide significance (p < 5×10-8). Signals at newly identified common-variant loci include coding variants in Mendelian cardiomyopathy genes (MYBPC3, BAG3), as well as regulators of lipoprotein (LPL) and glucose metabolism (GIPR, GLP1R), and are enriched in cardiac, muscle, nerve, and vascular tissues, as well as myocyte and adipocyte cell types. Gene burden studies across three biobanks (PMBB, UKB, AOU) including 27,208 individuals with HF and 349,126 without uncover exome-wide significant (p < 3.15×10-6) associations for HF and rare predicted loss-of-function (pLoF) variants in TTN, MYBPC3, FLNC, and BAG3. Total burden heritability of rare coding variants (2.2%, 95% CI 0.99-3.5%) is highly concentrated in a small set of Mendelian cardiomyopathy genes, and is lower than heritability attributable to common variants (4.3%, 95% CI 3.9-4.7%) which is more diffusely spread throughout the genome. Finally, we demonstrate that common-variant background, in the form of a polygenic risk score (PRS), significantly modifies the risk of HF among carriers of pathogenic truncating variants in the Mendelian cardiomyopathy gene TTN. These findings suggest a significant polygenic component to HF exists that is not captured by current clinical genetic testing.

Cardiovascular Genetics: The Role of Genetics in Predicting Risk.

Many cardiovascular disorders have underlying genetic causes. Clinical genetic testing for cardiovascular disease has become widely available and can be useful for diagnosis, management, and cascade screening in selected conditions and circumstances. This article gives an overview of the current state of genetic testing in inherited cardiovascular conditions, who can benefit from it, and the associated challenges.

Cardiovascular Characteristics of Patients with Genetic Variation in Desmoplakin (DSP).

BACKGROUND: Variants in the desmoplakin (DSP) gene have been recognized in association with the pathogenesis of arrhythmogenic right ventricular cardiomyopathy (ARVC) for nearly 20 years. More recently, genetic variation in DSP has also been associated with left-dominant arrhythmogenic cardiomyopathy. Data regarding the cardiac phenotypes associated with genetic variation in DSP have been largely accumulated from phenotype-first studies of ARVC. METHODS: We aimed to evaluate the clinical manifestations of cardiac disease associated with variants in DSP through a genotype-first approach employed in the University of Pennsylvania Center for Inherited Cardiovascular Disease registry. We performed a retrospective study of 19 individuals with "pathogenic" or "likely pathogenic" variants in DSP identified by clinical genetic testing. Demographics and clinical characteristics were collected. RESULTS: Among individuals with disease-causing variants in DSP, nearly 40% had left ventricular enlargement at initial assessment. Malignant arrhythmias were prevalent in this cohort (42%) with a high proportion of individuals undergoing primary and secondary prevention implantable cardioverter defibrillator implantation (68%) and ablation of ventricular arrhythmias (16%). Probands also experienced end-stage heart failure requiring heart transplantation (11%). CONCLUSIONS: Our data suggest DSP cardiomyopathy may manifest with a high burden of heart failure and arrhythmic events, highlighting its importance in the pathogenesis of dilated and arrhythmogenic cardiomyopathies. Targeted strategies for diagnosis and risk stratification for DSP cardiomyopathy should be investigated.

Left Ventricular Hypertrophy and Hypertrophic Cardiomyopathy in Adult Solid Organ Transplant Recipients.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) in pediatric solid organ transplant recipients has been reported in association with use of calcineurin inhibitors. However, data on the incidence and prevalence of HCM in adult posttransplant patients are limited. We sought to describe the clinical characteristics of solid organ transplant recipients who were diagnosed with HCM from 2011 to 2021 at a single center. METHODS: Patients who had undergone solid organ transplant and exhibited left ventricular hypertrophy with left ventricular wall thickness ≥13 mm on transthoracic echocardiography were included. Clinical history, pedigree analysis, clinical genetic testing, transthoracic echocardiography, cardiac magnetic resonance imaging, treatment, and follow-up testing results were collected. Categorical variables were described as n (%). Continuous variables were described with medians and interquartile ranges and compared using the Wilcoxon rank-sum and Kruskal-Wallis tests. A 2-sided P < 0.05 was considered statistically significant. RESULTS: Three lung, 5 kidney, and 4 liver transplant recipients from 12 different families were included. Seven patients (58%) did not carry a preexisting diagnosis of hypertension, and none had a history of aortic or subaortic stenosis. A majority of patients exhibited asymmetric septal hypertrophy (67%; medial septal thickness versus left ventricular posterior wall thickness 17 versus 13 mm; P < 0.001) and dynamic left ventricular outflow tract (LVOT) obstruction (58%). All patients were managed long term with calcineurin inhibitors. Clinical genetic testing in 6 patients identified 2 with disease-causing variants in 2 sarcomere genes, myosin binding protein-C and myosin heavy chain 7. Four patients (33%) underwent successful septal reduction therapy for treatment of symptomatic LVOT obstruction. CONCLUSIONS: Symptomatic HCM with dynamic LVOT obstruction can develop in solid organ transplant recipients, and genetic testing can identify individuals with sarcomeric HCM. Medical management and septal reduction therapies are treatment options for severe symptomatic disease.

Characteristics of Orofacial Clefting in Hawai'i.

Orofacial clefts are birth defects that require a multi-disciplinary approach for repair and ongoing management as there are often concomitant chronic health issues. Orofacial clefts can occur as an isolated finding, in combination with other anomalies, or as part of a genetic syndrome. When occurring as part of a genetic syndrome, the complexity of management increases and has lifelong implications for these individuals, their families, and their health care providers. Understanding factors related to the occurrence of syndromic orofacial clefting is important for birth defect research and for health care needs assessment and planning. Many research groups have addressed these issues by studying different populations and focusing on different questions. This study was a retrospective chart review of children with orofacial clefts cared for at a pediatric tertiary care center in Hawai'i to evaluate the proportion of isolated and syndromic clefts in the unique population of Hawai'i. The prevalence of syndromic and isolated clefts were then correlated with ethnicity and compared to the prevalence in other studies. Our goal was to increase knowledge about orofacial clefting in the population of Hawai'i. The proportion of isolated orofacial clefting in a population of patients with orofacial clefting cared for at a craniofacial clinic is similar to birth defect registry data for the Hawaiian Islands (59% vs 58%). Pacific Islanders in our study and prior study have a lower proportion of isolated clefts, suggesting that there are more craniofacial patients with syndromic and complex needs in this population. Further study is needed to clarify the etiologic factors.

The clinical application of gene editing: ethical and social issues.

Gene-editing techniques have progressed rapidly in the past 5 years. There are already ongoing human somatic gene-editing clinical trials for multiple diseases. And there has been one purported scenario of human germline gene editing in late 2018. In this paper, we will review the current state of the technology, discuss the ethical and social issues that surround the various forms of gene editing, as well as review emerging stakeholder data from professionals, the 'general public' and individuals and families dealing with genetic diseases potentially treatable by gene editing.

Attitudes of people with inherited retinal conditions toward gene editing technology.

BACKGROUND: The views of people with genetic conditions are crucial to include in public dialogue around developing gene editing technologies. This qualitative study sought to characterize the attitudes of people with inherited retinal conditions (retinitis pigmentosa [RP] and Leber congenital amaurosis [LCA]) toward gene editing. METHODS: Individuals with RP (N = 9) and LCA (N = 8) participated in semi-structured qualitative interviews about their experience with and attitudes toward blindness, and their views about gene editing technology for somatic, germline, and enhancement applications. RESULTS: Participants saw potential benefits from gene editing in general, but views about its use for retinal conditions varied and were influenced by personal perspectives on blindness. Those who felt more negatively toward blindness, particularly those with later onset blindness, were more supportive of gene editing for retinal conditions. Concerns about both germline and somatic editing included: the importance of informed consent; impacts of gene editing on social attitudes and barriers affecting blind people; and worries about "eliminating" blindness or other traits. CONCLUSION: People with RP and LCA have diverse attitudes toward gene editing technology informed by their own lived experience with disability, and many have concerns about how the ways in which it is discussed and implemented might affect them.

Participants and Study Decliners' Perspectives About the Risks of Participating in a Clinical Trial of Whole Genome Sequencing.

An increasing number of individuals are being recruited to whole genome sequencing (WGS) research. When asked hypothetically, the majority of the public express willingness to participate in this type of research, yet little is known about how many individuals will actually consent to research participation or what they perceive the risks to be. The MedSeq Project is a clinical trial exploring WGS in clinical care. We documented primary reason(s) for declining participation and reviewed audio-recorded informed consent sessions to identify participants' concerns. Of 514 individuals recruited, 173 (34%) actively declined, 205 (40%) enrolled, and the remaining 136 (26%) were ineligible, unresponsive or waitlisted. Although the majority of active decliners cited logistical barriers, 40% cited risks related to the ethical, legal, and social implications (ELSI) of WGS research. Participants similarly discussed ELSI-related concerns but felt the potential benefits of participation outweighed the risks. Findings provide insight into the perspectives of potential WGS research participants and identify potential barriers to participation.