Asta Literature Retrieval: Pathophysiology and clinical mechanisms of arrhythmogenic right ventricular cardiomyopathy. Core disease mechanisms,...

This report is retrieval-only and is generated directly from Asta results.

• Papers retrieved: 20
• Snippets retrieved: 20

Relevant Papers

[1] Special issue Heidelberg Heart II: Abstracts of oral and poster presentations

• Authors: W. Franke
• Year: 2012
• Venue: Cell and Tissue Research
• URL: https://www.semanticscholar.org/paper/969e98278c5ef7588af320ca0f980b09522c21e7
• DOI: 10.1007/s00441-012-1412-x
• PMCID: 3349853
• Citations: 1
• Summary: Interference with the architectural roles of desmosome molecules has been assumed to make an important contribution to tissue responses that lead to disease pathogenesis, functions that transcend their well-established roles in adhesion and IF-anchorage are emerging.
• Evidence snippets:
• Snippet 1 (score: 0.691) > A 16 -Disease mechanisms in arrhythmogenic cardiomyopathy: immunohistochemistry and beyond Jeffrey E. Saffitz Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA jsaffitz@bidmc.harvard.edu Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary myocardial disorder characterized by an especially high incidence of ventricular arrhythmias and sudden death. The identification of desmosomal gene mutations in ∼50 % of patients has led to the idea that ARVC is a disease of abnormal cell-cell adhesion. However, recent insights gained largely from studies of the human disease suggest a greater degree of complexity. These insights include observations that: (1) plakoglobin (γ-catenin) is consistently redistributed from desmosomes to intracellular/nuclear sites in all forms of ARVC regardless of the underlying mutation, (2) ARVC patients have elevated circulating cytokine levels and myocardial production of cytokines, and (3) disease flares often follow strenuous exercise in ARVC patients. Objective: to define the genetic and mechanistic basis of arrhythmogenic cardiomyopathy. Background: arrhythmogenic cardiomyopathy, previously known as arrhythmogenic right ventricular dysplasia (ARVD) or arrhythmogenic right ventricular cardiomyopathy (ARVC), is characterized by myocardial fibrofatty replacement, ventricular dysfunction, and arrhythmias associated with sudden death. Autosomal dominant inheritance is most common, and reduced penetrance is the rule of thumb, but the underlying basis of low penetrance is poorly understood. The causative genes identified to date are generally associated with desmosome function, the "final common pathway" of this disease. We previously described compound and digenic heterozygosity as a feature of this disorder which plays a role in the development of the clinical phenotype and the severity of disease.

[2] Prediction of Ventricular Arrhythmias in Patients at Risk of Sudden Cardiac Death

• Authors: K. Haugaa, J. Amlie, T. Edvardsen
• Year: 2011
• Venue: Unknown venue
• URL: https://www.semanticscholar.org/paper/366318c37e6eff3d2740558b56fc30d650950fd1
• DOI: 10.5772/20670
• Summary: In this report, a novel echocardiographic method will be presented in order to evaluate the cardiac contractility pattern in patients at increased risk of life-threatening arrhythmias.
• Evidence snippets:
• Snippet 1 (score: 0.652) > Arrhythmogenic right ventricular cardiomyopathy is an inheritable, chronic and progressive cardiomyopathy and is one of the leading causes of sudden unexpected cardiac death in previously healthy young individuals (Sen-Chowdhry, 2010a; Thiene, 1988). Prevalence has been estimated to be at least 1 in 1000 (Sen-Chowdhry, 2010a). Recent molecular genetic reports have revealed arrhythmogenic right ventricular cardiomyopathy as mainly a desmosomal disease (Xu, 2010). Mutations in one of the 5 desmosomal or 3 extra desmosomal genes so far identified, lead to progressive loss of myocytes, followed by fibro-fatty replacement. Penetrance is age and gender dependent and the progressive clinical picture is highly variable (Dalal, 2006). Four clinical stages have been documented: An early concealed phase, overt electrical disorder, isolated right heart failure (Fig 4a), and biventricular pump failure (Fig 4b) (Basso, 1996;Sen-Chowdhry, 2007;Sen-Chowdhry, 2010a). Importantly, life-threatening arrhythmias can occur with only discrete or even absent myocardial structural changes (Senwww.intechopen.com Chowdhry, 2010b). Risk stratification of ventricular arrhythmias and sudden cardiac death is therefore challenging. Mechanisms of arrhythmias in early stages of arrhythmogenic right ventricular cardiomyopathy are probably due to dysfunction of desmosomal proteins and disturbed cell to cell coupling (Saffitz, 2009). In later stages of arrhythmogenic right ventricular cardiomyopathy when structural abnormalities in the myocardium have developed, reentrant ventricular arrhythmias can occur in tissue with fibro fatty replacement. Therefore, electrical conduction delay with consequent electrical dispersion has been suggested as an important mechanism of ventricular arrhythmias (Amlie, 1997;Turrini, 2001). In a recent study we investigated if arrhythmogenic right ventricular cardiomyopathy patients had cardiac contraction heterogeneity assessed as mechanical dispersion and

[3] Update on Genes Associated with Arrhythmogenic Cardiomyopathy

• Authors: M. Vallverdú-Prats, M. Alcalde, G. Sarquella-Brugada, S. César, E. Arbelo et al.
• Year: 2020
• Venue: Cardiomyopathy - Disease of the Heart Muscle [Working Title]
• URL: https://www.semanticscholar.org/paper/1ffe68704d6dcbf0977f3587844705d96df69259
• DOI: 10.5772/INTECHOPEN.95332
• Citations: 1
• Summary: Recent advances in the knowledge regarding the genetic basis of arrhythmogenic cardiomyopathy are focused on, suggesting the existence of unknown genes as well as other genome alterations not yet discovered.
• Evidence snippets:
• Snippet 1 (score: 0.623) > Arrhythmogenic cardiomyopathy is an inherited rare cardiac disease characterized by progressive replacement of myocardium by fibrofatty tissue, leading to ventricular arrhythmias and sudden cardiac death. Structural abnormalities mainly occur in the right ventricle, but it is well recognized that also sole left ventricular involvement and even biventricular substitution is common, particularly in advanced stages of the disease. Several molecular mechanisms are involved in the phenotype of ACM such as myocardial inflammation and signaling pathways that cause fibrosis and adipogenesis. Today, most of these mechanisms are not completely understood. Task Force Criteria for the diagnosis of arrhythmogenic cardiomyopathy include several clinical tests and also genetic data. Despite progressive improvement in diagnosis, it is difficult to obtain conclusive risk stratification in families suffering from arrhythmogenic cardiomyopathy. Hundreds of rare alterations are reported in mainly genes encoding desmosomal proteins, but there are also other causal genes with several functions within the cardiac tissue. A comprehensive genetic analysis may identify the potential genetic cause of the disease in nearly 60% of cases. Genetic testing is especially useful in families with at least one affected member that carries a potential deleterious alteration because it allows early identification and adoption of therapeutic measures among relatives at risk of malignant arrhythmias. Currently, one of main challenges is the genetic interpretation and clinical translation of amount of genetic data generated by new genetic technologies. > Update on Genes Associated with Arrhythmogenic Cardiomyopathy DOI: http://dx.doi.org/10.5772/intechopen.95332

[4] Focus on arrhythmogenic right ventricular cardiomyopathy

• Authors: G. Sinagra, C. Cappelletto, A. de Luca, S. Romani, A. Paldino et al.
• Year: 2020
• Venue: European Heart Journal Supplements : Journal of the European Society of Cardiology
• URL: https://www.semanticscholar.org/paper/e4392c990ad29851d1c76e19a03845d6db0c611a
• DOI: 10.1093/eurheartj/suaa152
• PMID: 33239987
• PMCID: 7673615
• Citations: 7
• Summary: The main goal in the management of patients is the prevention of sudden cardiac death, where implantable cardioverter-defibrillator is the only effective therapeutic strategy.
• Evidence snippets:
• Snippet 1 (score: 0.615) > Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a primary heart muscle disease, characterized by progressive epi-endocardial replacement of cardiomyocytes with fibro-adipose tissue. Clinically, ARVC is characterized by ventricular arrhythmias, heart failure (HF), and sudden cardiac death (SCD). 1 The first descriptions of the disease were reported in the '70 s of the last century but only in 1995 ARVC become part of the WHO/IFSC (World Health Organization/International Society and Federation of Cardiology) Classification of Cardiomyopathies. > Originally the disease was known as 'Arrhythmogenic Dysplasia of the Right Ventricle' and was considered as a developmental defect of the right ventricle (RV) myocardium. > Since then, significant progress has been made in knowledge of pathogenetic mechanisms, natural history and clinical management of the disease. > Arrhythmogenic right ventricular cardiomyopathy is caused by a genetic defects, mainly affecting cell junction proteins (desmosomes). Structural alterations may be absent or mild in the initial stages of the disease, confined to a limited regions of the RV, the so called 'triangle of dysplasia'. With the progression of the disease also the left ventricle (LV) may be involved. > ][3][4][5][6] Growing evidences of genotypic overlap between ARVC and 'arrhythmic' Dilated Cardiomyopathy (caused by mutations of desmosomal genes, filamin or lamin) led to the definition of 'Arrhythmogenic Cardiomyopathy' (AC). 3,5,6 rrhythmogenic cardiomyopathy includes a heterogeneous spectrum of phenotypes, ranging from isolated involvement of the RV to exclusive involvement of the LV, sharing a common genetic basis and clinically characterized by electrical instability, that could lead to atrial or ventricular tachyarrhythmias and bradyarrhythmias.

[5] Arrhythmogenic Cardiomyopathy: Genetic Pathology, Inflammatory Syndrome, or both?

• Authors: Héctor O. Rodríguez
• Year: 2017
• Venue: EMJ Cardiology
• URL: https://www.semanticscholar.org/paper/a13b5f1adff7a0f90200a5d30040b7263a5f2f9b
• DOI: 10.33590/emjcardiol/10314768
• Summary: Findings taken from other sudden death-causing cardiomyopathies allow us to propose proinflammatory cytokines, such as tumour necrosis factor and interleukins 17 and 2, as possible serological markers of sudden death and/or ventricular dysfunction in order to conduct further research and identify diagnosis/prognosis markers for ACM.
• Evidence snippets:
• Snippet 1 (score: 0.596) > Arrhythmogenic cardiomyopathy (ACM), previously called arrhythmogenic right ventricular cardiomyopathy or arrhythmogenic right ventricular dysplasia, was classically defined as a fibro-fatty substitution of ventricular myocardium. Recent advances have given a more complete view of its pathophysiology, including genetic and electrophysiological criteria to classify the disease. Therefore, we can consider ACM as a ventricular arrhythmogenic syndrome with a structural substrate associated to intercalated disc protein mutations. The possible role of ionic disturbances in lethal arrhythmias make it challenging to specify a precise definition and adopt a rational approach to prevention and therapeutics and this should be acknowledged. > Initially, ACM was reported mainly in the right ventricle, 1 but may also implicate the left ventricle, as well as both ventricles simultaneously. ACM principally affects young men and can cause sudden death by ventricular arrhythmias, 2 especially in athletes, which is not always associated to structural changes in ventricular walls. As a result of these variables, we can classify ACM into ionic and non-ionic-associated origin by the presence or absence of structural ventricular changes. In this review, we explore the possible role of inflammation as a concomitant cause in ACM, a mechanism poorly explored in the literature and one that possibly should be included in further classifications. > ACM was first described early in the 1980s. Initially, it was reported as hypokinetic cardiomyopathy associated with non-ischaemic tachycardia. 1 Progressively, ACM was described as being in association with lethal arrhythmias, 3 functional myocardial involvement, 4 and biventricular affectation. 5,6 0][11][12][13] In the next sections, we briefly describe the most recent advances in the comprehension of the pathophysiology of ACM.

[6] Molecular Mechanisms of Inherited Arrhythmias

• Authors: C. Wolf, C. Berul
• Year: 2008
• Venue: Current Genomics
• URL: https://www.semanticscholar.org/paper/8dc574fc997d6e863ac851b4a75d122de6d9aa61
• DOI: 10.2174/138920208784340768
• PMID: 19440513
• PMCID: 2679644
• Citations: 26
• Influential citations: 3
• Summary: The molecular basis of inherited arrhythmias in structurally normal and altered hearts is summarized, which helps explain the molecular and functional mechanisms of long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and other electrical myopathies.
• Evidence snippets:
• Snippet 1 (score: 0.592) > Inherited arrhythmias can be life threatening, and are major cause of mortality and morbidity in developed nations. Identification of molecular pathways that increase susceptibility to arrhythmia is necessary to prevent disease occurrence, to improve current therapies and to target new drug development. In recent years, the discovery of pathogenic mutations in inherited arrhythmia syndromes has provided novel insights for the understanding and treatment of diseases predisposing to sudden cardiac death. In patients with the long QT syndromes (LQTS), genotype-phenotype relation studies [1] and genetic testing have influenced patient risk stratification [2] and refined treatment strategies [3]. > Arrhythmia mechanisms include abnormal automaticity, triggered activity, and re-entrant excitation. Each of these mechanisms can occur in any type of myocardial disease or in inherited cardiac arrhythmias. The current article focuses on molecular mechanisms of arrhythmias in the structurally abnormal and normal heart. Hypertrophic and dilated cardiomyopathies, as well as arrhythmogenic right ventricular dysplasia/cardiomyopathy are common substrates of inherited arrhythmias in the structurally abnormal heart. Genetic diseases causing arrhythmias in the structural normal heart, also called electrical myopathies, include the long QT syndromes, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), and non-defined familiar idiopathic ventricular fibrillation. Most, but not all of these disorders are caused by mutations in genes encoding cardiac ion-channel proteins. Among family members carrying an identical mutation in a single gene, remarkable phenotypic variability and expressivity may be observed, suggesting both environmental [4] and genetic modifiers [5].

[7] Arrhythmogenic cardiomyopathy: diagnosis, genetic background, and risk management

• Authors: J. Groeneweg, J. Groeneweg, J. Heijden, J. Heijden, D. Dooijes et al.
• Year: 2014
• Venue: Netherlands Heart Journal
• URL: https://www.semanticscholar.org/paper/7b6e9177653c6930262a978a3f44f7c979cfcce8
• DOI: 10.1007/s12471-014-0563-7
• PMID: 24817548
• PMCID: 4099433
• Citations: 28
• Influential citations: 3
• Summary: Therapeutic options in symptomatic patients include antiarrhythmic drugs, catheter ablation, and ICD implantation, and patients with AC and also all pathogenic mutation carriers should be advised against practising competitive and endurance sports.
• Evidence snippets:
• Snippet 1 (score: 0.591) > Arrhythmogenic right ventricular (RV) dysplasia/ cardiomyopathy (ARVD/C) is histopathologically characterised by progressive fibrofatty replacement of cardiomyocytes, primarily in the right ventricle [1][2][3]. However, histopathologically and functionally the left ventricle is affected in many cases and both ventricles are similarly affected by desmosomal and gap junctional protein redistribution [4,5]. Because of these observations, at present arrhythmogenic cardiomyopathy (AC) is the preferred terminology [6]. AC can be defined as a structural myocardial disease preceded by ventricular arrhythmias. Typical ARVD/C with predominant RV abnormalities can be considered a large and important subcategory of AC. Clinical diagnosis is made according to international consensus-based Task Force Criteria [7,8]. > The first series of ARVD/C patients was published in 1982 [1]. It was described as a developmental disease of the RV musculature, hence the terminology 'dysplasia'. In the past 25 years, increased insight into the development of the disease as well as the discovery of pathogenic gene mutations involved led to the current understanding that AC is a genetically determined cardiomyopathy. The molecular genetic substrate for the disease is mainly acknowledged in genes encoding desmosomal adhesion proteins in the intercalated disk [9][10][11][12][13][14]. > This review provides an overview of AC, from phenotypic and genetic features of the disease, to diagnosis, risk stratification and treatment options.

[8] Arrhythmogenic right ventricular cardiomyopathy: diverse substrate characteristics and ablation outcome.

• Authors: W. Cheng, F. Chung, Yenn‐Jiang Lin, L. Lo, S. Chang et al.
• Year: 2021
• Venue: Reviews in cardiovascular medicine
• URL: https://www.semanticscholar.org/paper/21563d7592478c853ce2ce3c54165855ba02fabf
• DOI: 10.31083/j.rcm2204136
• PMID: 34957771
• Citations: 7
• Summary: A better understanding of the pathogenesis, underlying arrhythmogenic substrates, and putative VT isthmus in ARVC contributes to a significant improvement in ablation outcomes through comprehensive endocardial and epicardial approaches.
• Evidence snippets:
• Snippet 1 (score: 0.590) > Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy caused by defective desmosomal proteins. The typical histopathological finding of ARVC is characterized by progressive fibrofatty infiltration of the right ventricle due to the dysfunction of cellular adhesion molecules, thus, developing arrhythmogenic substrates responsible for the clinical manifestation of ventricular tachycardia/fibrillation (VT/VF). Current guidelines recommend implantable cardiac defibrillator (ICD) implantation to prevent sudden cardiac death (SCD) in ARVC, especially for those experiencing VT/VF or aborted SCD, while antiarrhythmic drugs, despite their modest effectiveness and several undesirable adverse effects, are frequently used for those experiencing episodes of ICD interventions. Given the advances in mapping and ablation technologies, catheter ablation has been implemented to eliminate drug-refractory VT in ARVC. A better understanding of the pathogenesis, underlying arrhythmogenic substrates, and putative VT isthmus in ARVC contributes to a significant improvement in ablation outcomes through comprehensive endocardial and epicardial approaches. Regardless of ablation strategies, there is a diversity of arrhythmogenic substrates in ARVC, which could partly explain the nonuniform ablation outcome and long-term recurrences and reflect the role of potential factors in the modification of disease progression and triggering of arrhythmic events.

[9] Distinct Myocardial Transcriptomic Profiles of Cardiomyopathies Stratified by the Mutant Genes

• Authors: K. Sielemann, Z. Elbeck, A. Gärtner, A. Brodehl, C. Stanasiuk et al.
• Year: 2020
• Venue: Genes
• URL: https://www.semanticscholar.org/paper/9f8ceb185d87f8def9e3c9dc016922d53a936b4a
• DOI: 10.3390/genes11121430
• PMID: 33260757
• PMCID: 7768427
• Citations: 10
• Summary: Genotype-specific differences in regulated pathways, Gene Ontology (GO) terms as well as gene groups like secreted or regulatory proteins and potential candidate drug targets revealing specific molecular pathomechanisms for the four subtypes of genetic cardiomyopathies are identified.
• Evidence snippets:
• Snippet 1 (score: 0.589) > TTNtv are associated with incomplete penetrance and late onset heart failure, whereas patients with i.e., pathogenic RBM20 or LMNA mutations are affected by comparably early cardiomyopathies with incomplete penetrance [3]. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is most frequently associated with defects in the desmosome [10]. The right ventricle is mainly affected, but with ongoing disease, the left ventricle is significantly affected as well [12]. Left ventricular forms of arrhythmogenic cardiomyopathy (ACM), which is a broader description of ARVC, are almost missing in the 2010 update diagnostic criteria, which are therefore not entirely specific for the disease [13,14]. However, due to advances in the clinical, pathological and genetic architecture of ARVC [14], left ventricular involvement and left-dominant or biventricular subtypes are now increasingly recognized. Further, genotype-phenotype correlation studies have recently identified clinical forms of ARVC associated with early dominant left ventricular involvement, which may parallel or even exceed the severity of right ventricular involvement [13,15,16]. The introduction of the term ACM was therefore recently proposed by the Heart Rhythm Society/European Heart Rhythm Association (HRS/EHRA) [17] to embrace the different pathologies of the disease [14]. However, there is still a lack of diagnostic and prognostic data and of the genetic basis and pathogenesis of ACM [18]. In our study, we therefore included ACM cases and compared this cardiomyopathy to other forms based on their genotypes. Mutations in the desmosomal genes cause ARVC but other genes like e.g., FLNC [19] can be affected as well [3]. However, the most frequent affected gene is PKP2 (11-51%) [5] encoding the desmosomal plaque protein plakophilin 2. This protein mediates the molecular connection of the desmosomal cadherins with the cytolinker protein desmoplakin.

[10] Blockade of the Adenosine 2A Receptor Mitigates the Cardiomyopathy Induced by Loss of Plakophilin-2 Expression

• Authors: M. Cerrone, C. J. V. van Opbergen, K. Malkani, N. Irrera, Mingliang Zhang et al.
• Year: 2018
• Venue: Frontiers in Physiology
• URL: https://www.semanticscholar.org/paper/8535f5196dd6979a590543055872e433646d94c1
• DOI: 10.3389/fphys.2018.01750
• PMID: 30568602
• PMCID: 6290386
• Citations: 11
• Summary: Paracrine adenosine 2A receptor activation contributes to the progression of fibrosis and impaired cardiac function in animals deficient in PKP2.
• Evidence snippets:
• Snippet 1 (score: 0.583) > Arrhythmogenic right ventricular cardiomyopathy (ARVC, indicated also as "arrhythmogenic cardiomyopathy, ACM" or "arrhythmogenic right ventricular dysplasia, ARVD") is an inherited disease characterized by fibrofatty infiltration of right ventricular (RV) predominance, ventricular arrhythmias and high propensity for sudden death in the young (Basso et al., 2009). Cardiac arrest is often associated with exercise, and it is the first disease manifestation in a high proportion of probands. (Basso et al., 2009;Groeneweg et al., 2015) Most often the disease begins with a subclinical, concealed stage, followed by overt stages of RV predominance (though LV is often involved) then biventricular dilated cardiomyopathy and failure. (Basso et al., 2009;Groeneweg et al., 2015) The disease can progress to end-stage heart failure and in the absence of a heart transplant, death. At present, no medical treatment exists to prevent or delay the progression of the disease. > Familial ARVC is most commonly consequent to mutations in the gene coding for Plakophilin-2 (PKP2; Groeneweg et al., 2015), a protein classically defined as a component of the desmosome, though also known to participate in other cellular functions. The relation between PKP2 on one hand, and the structural disease that results from its absence or altered sequence, on the other, remains a matter of investigation. Previous studies on the molecular mechanisms leading to fibro-adiposis in ARVC have proposed that activation of the Hippo and Wnt pathways are the causative mechanisms of the structural disease (Garcia-Gras et al., 2006;Chen et al., 2014). Recently, Dubash et al. (2016) demonstrated an additional route whereby loss of PKP2 expression causes an increase in the expression of TGF-beta1, and activation of the p38-MAPK-dependent pro-fibrotic program.

[11] The Challenges of Diagnosis and Treatment of Arrhythmogenic Cardiomyopathy: Are We there yet?

• Authors: A. Spadotto, D. Morabito, A. Carecci, G. Massaro, G. Statuto et al.
• Year: 2022
• Venue: Reviews in Cardiovascular Medicine
• URL: https://www.semanticscholar.org/paper/c49b90d8007f1358bc50f48696245a86fda4560b
• DOI: 10.31083/j.rcm2308283
• PMID: 39076647
• PMCID: 11266951
• Citations: 6
• Summary: Background: we sought to review the evolution in the diagnosis and treatment of Arrhythmogenic Cardiomyopathy (ACM), a clinically multifaceted entity beyond the observation of ventricular arrhythmias, and the outcome of therapies aiming at sudden death prevention in a single center experience. Methods: retrospective analysis of the data of consecutive patients with an implanted cardioverter-defibrillator (ICD) and a confirmed diagnosis of ACM according to the proposed Padua Criteria, who were...
• Evidence snippets:
• Snippet 1 (score: 0.578) > This review on Arrhythmogenic Cardiomyopathy (ACM) focuses on its diagnostic challenges, on the debated role of risk-stratification of sudden cardiac death, and reports the outcome of ICD treatment for sudden death prevention in all cardiac phenotypes. ACM is a general term that encompasses a group of diseases different amongst themselves depending on type of pathologic involvement of the heart, aetiology, and genetics. While it is rationale to assign a specific nosographic classification to entities having a homogeneous genetic background (mutations of the same gene/group of genes) resulting in a common clinical phenotype (Figs. 1,2), it is much more clinically challenging to classify a disease whose phenotypic appearance is the outcome of several unlinked genetic diseases with different pathogenic mechanisms. Even more difficult is disease classification when different mutations of the same gene are disease-causative in the same organ with differ-ent phenotypes (hypertrophic vs arrhythmogenic disease). Debate as to whether a genomic-based classification of diseases or a clinical phenotype-based one is more appropriate is ongoing. We focus on ACM phenotype expressed as right ventricular, biventricular, and left ventricular involvement of the heart caused by progressive replacement of the myocardium by fibrotic or fibro-fatty tissue, which acts as an arrhythmogenic substrate predisposing to lifethreatening ventricular arrhythmias and heart failure due to systolic ventricular dysfunction, caused by inherited genetic abnormalities. The earliest clinical manifestations of these diseases are ventricular arrhythmias, typically occurring between the third and the fourth decade, though they represent a relevant cause of sudden death in adolescents, especially in the physically active and in high-level athletes [1]. Sudden cardiac death (SCD) can be the first manifestation in a minority of patients, thereby heightening medical attention in the event ventricular arrhythmias are detected in otherwise healthy and young individuals.

[12] Arrhythmogenic Cardiomyopathy PKP2-Related: Clinical and Functional Characterization of a Pathogenic Variant Detected in Two Italian Families

• Authors: E. Marchionni, Sonia Lomuscio, A. Latini, M. Murdocca, F. Romeo et al.
• Year: 2025
• Venue: Genes
• URL: https://www.semanticscholar.org/paper/afff57f85745a4204acf47c04f8d5948b7866657
• DOI: 10.3390/genes16040419
• PMID: 40282378
• PMCID: 12027432
• Summary: The clinical onset of ACM can be Sudden Cardiac Death, and hence, it is recommended to perform a segregation test on first-degree relatives of pathogenic variant carriers, even if they are asymptomatic, with the purpose of promptly detecting those at risk.
• Evidence snippets:
• Snippet 1 (score: 0.573) > Arrhythmogenic Cardiomyopathy (ACM, MIM 609040) is a genetic disease characterized by incomplete penetrance and a wide variable expressivity. In most cases, it is caused by pathogenic variants in genes encoding for desmosomal proteins, which are involved in cardiomyocyte adhesion [1]. Among the desmosomal genes, Plakophilin-2 (PKP2, MIM 602861) is the most frequently associated with ACM [2]. Reduced expression of desmosomal proteins has been shown to induce cardiac dysfunction [3]. This is attributable to a progressive weakening of cell-to-cell junctions leading to fibrotic remodeling areas, due to a decrease in mechanical traction tolerance [4]. > The consequential cardiomyocyte apoptosis results in an uneven slowing of signal propagation, which implies the development of arrhythmias in affected patients. This explains why ACM is associated with a high risk of Sudden Cardiac Death (SCD), especially when PKP2 mutation carriers have not undergone appropriate cardiological follow-up [5]. > Clinical diagnosis of ACM is based on evaluating signs and symptoms, imaging, histological characterization, and electrocardiographic features. It is also important to obtain medical information about patients' pedigrees, as approximately 30% to 50% of those affected have a positive family history [6]. > According to the 2010 Revised Task Force Criteria for the Diagnosis of Arrhythmogenic Cardiomyopathy (formerly known as Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia), all the clinical features detected through the cardiological assessment can be sorted into six different categories, each consisting of major and minor criteria: > Morphofunctional Alterations (right ventricular (RV) dilatation or wall motion bnormalities); 2. > Myocardium Histology (fibro-adipose replacement); 3. > Repolarization Abnormalities (inverted T waves in right precordial leads); 4. > Depolarization/Conduction Abnormalities (ε waves in the right precordial leads, prolonged QRS duration); 5.

[13] The genetic background of arrhythmogenic right ventricular cardiomyopathy

• Authors: S. Ohno
• Year: 2016
• Venue: Journal of Arrhythmia
• URL: https://www.semanticscholar.org/paper/913fda12a4950f207552feb583a7d267a58e34a5
• DOI: 10.1016/j.joa.2016.01.006
• PMID: 27761164
• PMCID: 5063271
• Citations: 76
• Influential citations: 8
• Summary: The clinical issues of ARVC from the genetic background are discussed and many studies have reported clinical manifestations of, prognosis for, and appropriate therapies for AR VC from the perspective of gene mutations.
• Evidence snippets:
• Snippet 1 (score: 0.564) > Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by degeneration of the right ventricle and ventricular tachycardia originating from the right ventricle. Additionally, the disease is an inherited cardiomyopathy that mainly follows the autosomal dominant pattern. More than 10 genes have been reported as causative genes for ARVC, and more than half of ARVC patients carry mutations in desmosome related genes. The desmosome is one of the structures involved in cell adhesion and its disruption leads to various diseases, including a skin disease called pemphigus. Among desmosome genes, mutations in PKP2 are most frequently identified in ARVC patients. Although the genotype–phenotype correlations remain to be fully studied, many studies have reported clinical manifestations of, prognosis for, and appropriate therapies for ARVC from the perspective of gene mutations. A collective review of these reports would enhance the understanding of ARVC pathogenesis and clinical manifestation. This review discusses the clinical issues of ARVC from the genetic background.

[14] Using Zebrafish Animal Model to Study the Genetic Underpinning and Mechanism of Arrhythmogenic Cardiomyopathy

• Authors: Yujuan Niu, Yuanchao Sun, Yuting Liu, Ke Du, Xiaolei Xu et al.
• Year: 2023
• Venue: International Journal of Molecular Sciences
• URL: https://www.semanticscholar.org/paper/1ea7360cab3224c8bbe08bf376ceb2f4c216ca49
• DOI: 10.3390/ijms24044106
• PMID: 36835518
• PMCID: 9966228
• Citations: 5
• Summary: Arrhythmogenic cardiomyopathy (ACM) is largely an autosomal dominant genetic disorder manifesting fibrofatty infiltration and ventricular arrhythmia with predominantly right ventricular involvement. ACM is one of the major conditions associated with an increased risk of sudden cardiac death, most notably in young individuals and athletes. ACM has strong genetic determinants, and genetic variants in more than 25 genes have been identified to be associated with ACM, accounting for approximately...
• Evidence snippets:
• Snippet 1 (score: 0.562) > Arrhythmogenic cardiomyopathy (ACM) is an updated term for the heart muscle disorder originally known as arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), manifesting as malignant ventricular arrhythmias and fibrofatty infiltration in the myocardium of both ventricles, with right ventricular involvement being more common. Depending on the patient cohorts studied, the prevalence of ACM is estimated to be 1 case per 2000 to 5000 individuals in the general population [1]. While recognized as a rare form of cardiac disease, ACM with sustained ventricular arrhythmia represents a major risk condition, causing a significant proportion of sudden cardiac deaths, especially in young individuals and athletes [2,3]. > In the 2000s, through pedigree linkage analysis, homozygous truncating mutations in the junction plakoglobin (JUP) and desmoplakin (DSP) genes were identified in parallel to cause ACM that overlaps with cardio-cutaneous syndromes, representing the first two genetic studies to recognize ACM as an inheritable type of cardiomyopathy [4,5]. Since then, over the past almost two decades, mostly through the combined approaches of familial genetic linkage and candidate gene sequencing, numerous pathogenic variants in more than 25 genes have been identified to cause ACM, accounting for up to 60% of ACM cases [6][7][8][9]. These findings underscore the strong genetic determinant of ACM. However, the genotype-phenotype relationship in ACM patients remains complex; even for ACM cases harboring the same identified gene mutations, disease onset and disease severity can manifest with highly variable expressivity, likely due to the contributions of other comorbidities combined with different genetic background and environmental factors [10,11]. In addition, for patients with known genetic causes, the molecular mechanisms underlying their ACM disease progression remain poorly understood. Currently, clinical management of ACM patients mainly focuses on the general control of heart failure and the prevention of arrhythmic sudden cardiac death (SCD) [12].

[15] Contemporary genetic testing in inherited cardiac disease: tools, ethical issues, and clinical applications

• Authors: F. Girolami, G. Frisso, M. Benelli, L. Crotti, M. Iascone et al.
• Year: 2017
• Venue: Journal of Cardiovascular Medicine (Hagerstown, Md.)
• URL: https://www.semanticscholar.org/paper/1685069e7fbb47642dbd475d1b5cca90133ea1c6
• DOI: 10.2459/JCM.0000000000000589
• PMID: 29176389
• PMCID: 5732648
• Citations: 50
• Influential citations: 1
• Summary: This document reflects the multidisciplinary, ‘real-world’ experience required when implementing genetic testing in cardiomyopathies and arrhythmic syndromes, along the recommendations of various guidelines.
• Evidence snippets:
• Snippet 1 (score: 0.562) > Inherited cardiac diseases comprise a wide and heterogeneous spectrum of diseases of the heart, including the cardiomyopathies and the arrhythmic diseases in structurally normal hearts, that is, channelopathies. 1 With a combined estimated prevalence of 3% in the general population, 1 these conditions represent a relevant epidemiological entity worldwide, and are a major cause of cardiac morbidity and mortality in the young. The extraordinary progress achieved in molecular genetics over the last three decades has unveiled the complex molecular basis of many familial cardiac conditions, paving the way for routine use of gene testing in clinical practice. According to the European Society of Cardiology classification, cardiomyopathies are divided into dilated cardiomyopathy (DCM), hypertrophic (HCM), arrhythmogenic right ventricular (ARVC), restrictive and unclassified, although in practice there may be extensive overlap between these phenotypes. 2 The hypokinetic nondilated cardiomyopathy has been recently added to the prior major phenotypes. 3 The American Heart Association advanced a gene-based classification 4 so that HCM was viewed as a disease of the sarcomere 5 and ARVC as a disease of intercellular junctions, caused by mutations in genes encoding desmosomal proteins. 6,7 The genetics of familial DCM is far more heterogeneous: currently, DCM mutations have been described in genes encoding cytoskeletal, sarcomeric, desmosomal, nucleoskeletal, mitochondrial, and calcium handling proteins. 8 Additionally, sarcomere mutations have been identified in association with more complex disorders of cardiac structure and function, including restrictive physiology and left ventricular noncompaction. 4 In the same manner, ARVC e DCM phenotypes can be a different expression of variants in the same genes (Lamin A, Filamin C, and desmosomal genes). 7 Channelopathies, generally caused by mutations in proteins constituting or regulating cardiac ion channels, include the long-Q waves and T waves (QT) syndrome (LQTS), the short-QT syndrome (SQTS), Brugada syndrome (BrS), and

[16] Experimental models of spontaneous ventricular arrhythmias and of sudden cardiac death.

• Authors: M. Štengl
• Year: 2010
• Venue: Physiological research
• URL: https://www.semanticscholar.org/paper/2d6baf492e82162573b5c2be03a82a8d95b314fd
• DOI: 10.33549/PHYSIOLRES.932001
• PMID: 20626217
• Citations: 23
• Summary: In this review, a number of experimental animal models with high incidence of sudden cardiac death were developed and are intensively studied to get new insights into theudden cardiac death mechanisms.
• Evidence snippets:
• Snippet 1 (score: 0.560) > Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiac disease associated with substantial cardiovascular morbidity and sudden death in young people (Thiene et al. 1988). Causative mutations were identified in genes encoding desmosomal proteins (Basso et al. 2009). A spontaneous, genetically transmitted model of arrhythmogenic right ventricular cardiomyopathy, closely resembling the human disease, was described in boxer dogs (Basso et al. 2004). Clinical events included sudden death, ventricular arrhythmias of suspected right ventricular origin, syncope and heart failure. Severe right ventricular myocyte loss with replacement by fatty or fibrofatty tissue was present. The cardiomyopathy in the model was shown to be associated with a substantial loss of gap junction plaques as well as with remodeling of other intercalated disc structures (Oxford et al. 2007). Calstabin2 deficiency associated with a significantly increased open probability of single sarcoplasmic reticulum release channels was also identified and suggested as a potential mechanism for calcium leak-induced ventricular arrhythmias in these dogs (Oyama et al. 2008).

[17] Extracellular vesicles in cardiomyopathies: A narrative review

• Authors: A. Rizzuto, A. Faggiano, C. Macchi, S. Carugo, C. Perrino et al.
• Year: 2023
• Venue: Heliyon
• URL: https://www.semanticscholar.org/paper/d9f9d3f5e11a4f42af7d1ead3cff3c874fff64a4
• DOI: 10.1016/j.heliyon.2023.e23765
• PMID: 38192847
• PMCID: 10772622
• Citations: 5
• Influential citations: 1
• Summary: The aims of this narrative review are to elucidate the potential role of EVs in the paracrine cell-to-cell communication among cardiac tissue compartments, in aiding the diagnosis of the diverse subtypes of cardiomyopathies in a minimally invasive manner, and to address whether certain molecular and phenotypical characteristics of EVs may correlate with cardiomyopathy disease phenotype and severity.
• Evidence snippets:
• Snippet 1 (score: 0.559) > Cardiomyopathies refer to myocardial disorders affecting the heart muscle, in which structural and functional abnormalities are observed, in the absence of diseases such as coronary artery disease, hypertension, valvular disease, or congenital heart disease that could account for the observed abnormalities. According to the 2023 European Society of Cardiology (ESC) guidelines for the management of cardiomyopathies, morphological traits (ventricular hypertrophy: left and/or right; ventricular dilation: left and/or right; non-ischemic ventricular scar) and functional characteristics (global and/or regional ventricular systolic and/or diastolic dysfunction) are clinically employed to categorize five distinct cardiomyopathy phenotypes: hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), non-dilated left ventricular cardiomyopathy (NDLVC), arrhythmogenic right ventricular cardiomyopathy (ARVC), and restrictive cardiomyopathy (RCM). Furthermore, the guidelines also specify the existence of syndromic and metabolic cardiomyopathies, including Anderson-Fabry disease, RASopathies, Friedreich ataxia, and Glycogen storage disorders [4]. > Whilst this phenotypic description is essential in paving the diagnostic and therapeutic pathway, the exact evolving nature of cardiomyopathies, along with their underlying aetiological complexities, are yet to be fully elucidated [5]. Within this context, biomarkers represent putative tools for identifying high-risk patients in a prompt manner, unveiling potential risk associations with disease progression and outcomes, and may also provide insights on unexplored molecular mechanisms at the basis of the pathophysiology of these disorders. > Thus, the aim of the present narrative review is to summarize the current knowledge on EVs in the setting of cardiomyopathies and to elucidate whether certain molecular and phenotypical characteristics of EVs (e.g., miRNA content) may correlate with cardiomyopathy phenotypes and severity.

[18] Familial Arrhythmogenic Cardiomyopathy: Clinical Determinants of Phenotype Discordance and the Impact of Endurance Sports

• Authors: S. Costa, A. Gasperetti, A. Medeiros-Domingo, D. Akdis, C. Brunckhorst et al.
• Year: 2020
• Venue: Journal of Clinical Medicine
• URL: https://www.semanticscholar.org/paper/cfa322e3e3e111e155b2634afedc42ee1aa5c0bc
• DOI: 10.3390/jcm9113781
• PMID: 33238575
• PMCID: 7700696
• Citations: 11
• Summary: Different phenotypic expression profiles of ACM are analyzed in the context of the same familial genetic mutation by studying nine adult cases from four different families with four different familial variants from the Swiss Arrhythmogenic Right Ventricular Cardiomyopathy Registry.
• Evidence snippets:
• Snippet 1 (score: 0.558) > Arrhythmogenic cardiomyopathy (ACM) is primarily a familial disease with autosomal dominant inheritance. Incomplete penetrance and variable expression are common, resulting in diverse clinical manifestations. Although recent studies on genotype–phenotype relationships have improved our understanding of the molecular mechanisms leading to the expression of the full-blown disease, the underlying genetic substrate and the clinical course of asymptomatic or oligo-symptomatic mutation carriers are still poorly understood. We aimed to analyze different phenotypic expression profiles of ACM in the context of the same familial genetic mutation by studying nine adult cases from four different families with four different familial variants (two plakophilin-2 and two desmoglein-2) from the Swiss Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Registry. The affected individuals with the same genetic variants presented with highly variable phenotypes ranging from no disease or a classical, right-sided disease, to ACM with biventricular presentation. Moreover, some patients developed early-onset, electrically unstable disease whereas others with the same genetic variants presented with late-onset electrically stable disease. Despite differences in age, gender, underlying genotype, and other clinical characteristics, physical exercise has been observed as the common denominator in provoking an arrhythmic phenotype in these families.

[19] Altered Electrical, Biomolecular, and Immunologic Phenotypes in a Novel Patient-Derived Stem Cell Model of Desmoglein-2 Mutant ARVC

• Authors: Robert N Hawthorne, A. Blazeski, Justin Lowenthal, Suraj Kannan, R. Teuben et al.
• Year: 2021
• Venue: Journal of Clinical Medicine
• URL: https://www.semanticscholar.org/paper/6da345fa7e27ceec663bb0cbe8949a5e52f4f9a7
• DOI: 10.3390/jcm10143061
• PMID: 34300226
• PMCID: 8306340
• Citations: 36
• Influential citations: 1
• Summary: A novel human induced pluripotent stem cell-derived cardiomyocyte model of ARVC from a patient with a c.2358delA variant in desmoglein-2 (DSG2) found DSG2Mut hiPSC-CMs could underlie early mechanisms of disease manifestation in ARVC patients.
• Evidence snippets:
• Snippet 1 (score: 0.555) > Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited, progressive arrhythmogenic cardiomyopathy (ACM) characterized by cardiomyocyte death and fibrofatty scarring in the ventricular myocardium. Clinically, patients with ARVC develop ventricular arrhythmias which often present more frequently as the disease progresses. > ARVC is estimated to account for more than 10% of all cardiovascular deaths in patients younger than 65 years old and is a leading cause of sudden cardiac death (SCD) in young athletes [1][2][3]. ARVC prevalence is approximately 1:1000-1:5000, and patients are typically diagnosed in young adulthood; diagnosis before puberty is extremely rare [4][5][6]. > While the pathophysiology underlying ARVC is still poorly understood, there has been general scientific consensus that the common final pathway of the disease involves the disruption of the cardiac desmosome, a cellular structure present at the intercalated disc that is critical for intercellular mechanical and electrical coupling between cardiomyocytes [7,8]. Pathogenic variants in any of the five cardiac desmosomal genes -plakoglobin (JUP), plakophilin-2 (PKP2), desmoglein-2 (DSG2), desmoplakin (DSP) and desmocollin-2 (DSC2)-account for more than 60% of inherited ARVC and have a combined estimated prevalence of approximately 1.2 per 1000 in the general population [9]. Among these, PKP2 and DSG2 are the first and second most common variants, respectively [6,10]. > Determining the pathogenic mechanisms underlying ARVC has proven difficult. The study of human tissue is challenging, as ARVC is frequently diagnosed in later stages of disease (e.g., myocardial scarring) when retrieval of a myocardial biopsy presents significant risk of cardiac perforation.

[20] Misdiagnosed myocarditis in arrhythmogenic cardiomyopathy induced by a homozygous variant of DSG2: a case report

• Authors: Xuwei Liu, Y. Zhang, Wen‐Jing Li, Qian Zhang, Lei Zhou et al.
• Year: 2023
• Venue: Frontiers in Cardiovascular Medicine
• URL: https://www.semanticscholar.org/paper/1236e1d0916ff4dccfecafe269c149a1847b4987
• DOI: 10.3389/fcvm.2023.1150657
• PMID: 37288269
• PMCID: 10242036
• Citations: 5
• Summary: A rare pediatric case initially presenting as myocarditis that transitioned into ACM during follow-up is reported, expanding the clinical feature spectrum of DSG2-associated ACM at an early age.
• Evidence snippets:
• Snippet 1 (score: 0.553) > Misdiagnosed myocarditis in arrhythmogenic cardiomyopathy induced by a homozygous variant of DSG2: a case report 1. Introduction Arrhythmogenic right ventricular cardiomyopathy (ARVC, OMIM:#610476) is an inherited heart muscle disease characterized by the loss of the ventricular myocardium and fibrofatty replacement, which predisposes patients to fatal ventricular arrhythmias and sudden cardiac death (SCD) (1,2). A genetic etiology has been identified for most inherited cardiovascular diseases, especially cardiomyopathies, with the rapid development of sequencing techniques. Regarding the molecular mechanism, ARVC has been identified as being related to pathogenetic variants in desmosomes and adherens junctions, which are critical for establishing cell-cell junctions and maintaining intercellular communication (3,4). Thus, the disease group ACM should be considered to define the broader spectrum of the phenotypic expressions of the disease (4). From a molecular perspective, multiple genes encoding desmosomal proteins, such as plakophilin-2 (PKP2), desmoplakin (DSP), DSG2, desmocollin (DSC2), and plakoglobin (JUP), account for 50% of patients with ACM in different cohorts (5,6). However, there are other genetic (non-desmosomal) and non-genetic causes of the disease. The non-desmosomal genes include DES, LMNA, SCN5A, PLN, TMEM43, and TGFB3, which are not involved in the molecular formation of desmosomes and participate in several types of ARVC origins (2). The inclusion of sarcomere-, ion transporter-, and cytokine-related genes would increase the percentage of patients positive for molecular characterization. However, the incomplete dominance and variable expressiveness of certain variants suggest that environmental factors play an important role. Initially, ARVC was considered to mainly cause right ventricular lesions and impair the function of the right ventricle.

Notes

• This provider combines search_papers_by_relevance with snippet_search.
• No synthesis or second-stage model call is performed.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Comprehensive Disease Research Report

1. Disease Information

Overview. Arrhythmogenic right ventricular cardiomyopathy (ARVC), now more broadly termed arrhythmogenic cardiomyopathy (ACM) to reflect biventricular and left-dominant phenotypic variants, is a heritable heart muscle disease characterized by progressive fibrofatty replacement of ventricular myocardium, predominantly affecting the right ventricle (RV), though left ventricular (LV) and biventricular forms are increasingly recognized. The disease is a leading cause of sudden cardiac death (SCD) in young people and athletes, often presenting with ventricular arrhythmias that may precede overt structural changes detectable on imaging. It is fundamentally a "disease of the desmosome" in the majority of genotyped cases, reflecting pathogenic variants in genes encoding cardiac desmosomal proteins that mediate mechanical cell-cell adhesion between cardiomyocytes, though non-desmosomal genetic causes (e.g., in genes encoding intermediate filament, nuclear envelope, or ion channel proteins) are also described.

Key identifiers: - OMIM: ARVC is genetically heterogeneous, with multiple OMIM phenotype entries corresponding to different loci/genes: ARVC1 (OMIM #107970, TGFB3), ARVC2 (OMIM #600996, RYR2), ARVC3 (OMIM #602086), ARVC4 (OMIM #602087, TTN), ARVC5 (OMIM #604400, TMEM43), ARVC6 (OMIM #604401), ARVC7 (OMIM #609160, DES), ARVC8 (OMIM #607450, DSP), ARVC9 (OMIM #609040, PKP2), ARVC10 (OMIM #610193, DSG2), ARVC11 (OMIM #610476, DSC2), ARVC12 (OMIM #611528, JUP), ARVC13 (OMIM #615616, unknown), and Naxos disease (OMIM #601214, JUP-related recessive cardiocutaneous syndrome) and Carvajal syndrome (OMIM #605676, DSP-related). - Orphanet: ORPHA:247 (Arrhythmogenic right ventricular cardiomyopathy) - MONDO: MONDO:0016587 is used in many ontology resources for ARVC (curators should verify against the local MONDO adapter before use, per dismech ontology practice, rather than assuming this ID is exact). - ICD-10: I42.8 (Other cardiomyopathies) is the commonly assigned code, as ICD-10 lacks an ARVC-specific code; ICD-11 includes more granular cardiomyopathy codes under BC43. - MeSH: D029094 (Arrhythmogenic Right Ventricular Dysplasia) - HPO term for the phenotype itself: HP:0031311 (Arrhythmogenic right ventricular cardiomyopathy) — curators should verify current HPO term ID.

Synonyms: Arrhythmogenic right ventricular dysplasia (ARVD); arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C); arrhythmogenic cardiomyopathy (ACM, the modern umbrella term encompassing right-dominant, biventricular, and left-dominant forms); Naxos disease (autosomal recessive cardiocutaneous variant with palmoplantar keratoderma and woolly hair); Carvajal syndrome (DSP-related left-dominant recessive cardiocutaneous variant).

Evidence basis. Most foundational literature is derived from aggregated disease-level resources: multi-center registries (e.g., the North American ARVC Registry, Johns Hopkins ARVC/C Program registry), family/pedigree studies, and genotype-phenotype correlation cohorts, supplemented increasingly by individual-patient genomic and EHR data as genetic testing has become standard of care.

2. Etiology

Primary causes. ARVC/ACM is a genetic disease of cell-cell junctions — predominantly desmosomal — in the majority of index cases where a pathogenic variant is identified (roughly 50-60% of clinically definite cases in most cohorts, though gene detection rates vary by cohort ascertainment). The prevailing "final common pathway" hypothesis holds that desmosomal dysfunction destabilizes intercalated discs, leading to cardiomyocyte detachment (particularly under the mechanical stress of exercise), cell death, fibrofatty replacement, and consequent electrical instability and structural remodeling. A parallel and complementary mechanistic thread implicates disrupted Wnt/β-catenin signaling — displaced plakoglobin (a desmosomal and Wnt-pathway shared protein) translocates to the nucleus, suppressing canonical Wnt signaling and promoting adipogenic and fibrogenic gene expression programs in cardiac progenitor/mesenchymal populations (Garcia-Gras et al., PMID:16467587, demonstrated this mechanism in a JUP-related mouse model).

Genetic risk/causal factors: - PKP2 (plakophilin-2): The single most commonly mutated gene, accounting for ~25-45% of genotyped cases in Western cohorts (autosomal dominant). - DSP (desmoplakin): Associated with both right-dominant and, notably, left-dominant/biventricular arrhythmogenic cardiomyopathy; DSP cardiomyopathy has a distinct "hot phase" myocarditis-like presentation with troponin release. - DSG2 (desmoglein-2), DSC2 (desmocollin-2): Less common desmosomal genes. - JUP (plakoglobin): Autosomal dominant forms and, in the homozygous/compound heterozygous state, Naxos disease. - TMEM43: Associated with a particularly malignant, highly penetrant form (Newfoundland variant, p.S358L) with high SCD risk. - Non-desmosomal genes: DES (desmin), TTN (titin), PLN (phospholamban, p.R14del founder variant especially in Dutch populations, associated with both DCM and ACM phenotypes), RYR2 (ryanodine receptor 2, historically linked to "ARVC2"/effort-induced polymorphic VT overlapping with CPVT), LMNA, FLNC (filamin C, associated with left-dominant arrhythmogenic cardiomyopathy and high arrhythmic risk), CDH2 (N-cadherin), CTNNA3 (α-T-catenin), SCN5A (overlap with Brugada/conduction disease phenotypes), and TGFB3. - Inheritance pattern: Predominantly autosomal dominant with incomplete and age-related penetrance and highly variable expressivity; autosomal recessive forms (Naxos, Carvajal) are associated with cardiocutaneous phenotypes. - Digenic/compound heterozygous disease burden: A substantial minority of patients carry more than one pathogenic/likely pathogenic variant (often in different desmosomal genes), which correlates with more severe and earlier-onset disease — this is a well-documented genetic modifier phenomenon in ARVC (Rigato et al. and Bhonsale et al. literature; specific PMIDs should be verified during curation).

Environmental/lifestyle risk factors: - Endurance/competitive exercise is the most robustly documented environmental risk factor — it accelerates disease onset, penetrance, and progression, and increases risk of malignant ventricular arrhythmia and SCD, particularly in genotype-positive individuals. This is a cornerstone finding across multiple cohorts (e.g., James et al., Circulation, and related work from the Johns Hopkins registry). - Age and sex: Male sex is associated with higher penetrance and more severe phenotype expression in most (though not all) genetic subtypes; typical age of symptom onset is adolescence to middle adulthood (commonly 20s-40s), with rare pediatric presentations. - Family history: A first-degree relative with ARVC or premature SCD is a major risk indicator and is incorporated into the 2010 Task Force diagnostic criteria as a minor/major criterion.

Protective factors: Restriction from competitive/endurance exercise in genotype-positive individuals is the principal actionable "protective" intervention supported by observational cohort data, though this is a management recommendation rather than a biological protective factor per se. No specific protective genetic variants are well established in the literature at a level suitable for confident citation; curators should search ClinVar/gnomAD/GWAS Catalog for modifier alleles rather than assume none exist.

Gene-environment interaction. The clearest G×E interaction in ARVC is the exercise-genotype interaction described above: mechanical/hemodynamic stress on a desmosomally-weakened intercalated disc accelerates myocyte detachment and disease progression, meaning the same pathogenic variant produces markedly different phenotypic severity depending on exercise exposure — a pattern well supported by both human cohort data and mouse models (e.g., Kirchhof et al., Circulation 2006, PMID:16769908, on exercise effects in a heterozygous plakoglobin-deficient mouse model).

3. Phenotypes

ARVC/ACM phenotypes span structural, electrical, and (in syndromic recessive forms) cutaneous domains.

Clinical signs/symptoms: - Palpitations — frequent presenting symptom, related to ventricular ectopy/VT (suggested HP term: HP:0001962 Palpitations) - Syncope — exertional or arrhythmic syncope is a major diagnostic criterion and high-risk marker (HP:0001279 Syncope) - Sudden cardiac death / cardiac arrest — may be the first manifestation, especially in young athletes (HP:0001645 Sudden cardiac death, if available; otherwise use relevant HPO death/arrhythmia terms) - Ventricular tachycardia, typically with left bundle branch block (LBBB) morphology reflecting RV origin (HP:0004756 Ventricular tachycardia) - Right ventricular dilation/dysfunction (HP:0011663 Right ventricular dilatation; HP:0001635 Congestive heart failure in advanced disease) - Epsilon waves on ECG — a classic, highly specific but insensitive major Task Force criterion - T-wave inversion in right precordial leads (V1-V3) — common ECG finding, a major/minor criterion depending on age and QRS duration - Fibrofatty myocardial replacement on imaging/histology — the structural hallmark - Heart failure symptoms in advanced/burnt-out phase, sometimes indistinguishable from dilated cardiomyopathy

Cutaneous phenotypes (syndromic recessive forms): - Woolly hair (HP:0002415) and palmoplantar keratoderma (HP:0000982) — cardinal features of Naxos disease (JUP) and, to a variable degree, Carvajal syndrome (DSP)

Phenotype characteristics: - Age of onset: Classically second to fourth decade of life; the disease is thought to evolve through phases — a "concealed" subclinical phase (structurally near-normal but arrhythmia risk present), an "overt electrical" phase, and a "structural/heart failure" phase — as described in the classic natural history model (Thiene, Basso, Corrado literature from the Padua group). - Severity/progression: Highly variable; disease is generally progressive but rate varies considerably by genotype (e.g., TMEM43 p.S358L and compound/digenic desmosomal genotypes associate with more aggressive, earlier disease), sex, and exercise exposure. - Frequency among affected individuals: Symptom/sign frequencies vary substantially by cohort and genotype; T-wave inversion in right precordial leads is reported in roughly 50-85% of definite ARVC cases depending on series; epsilon waves are far less common (reported in a minority, often <30%, of cases, being highly specific but insensitive).

Quality of life impact. Disease burden includes psychological impact of implantable cardioverter-defibrillator (ICD) therapy (shocks, anxiety, activity restriction), exercise restriction itself (particularly impactful for athletes), and progression to heart failure in advanced cases requiring transplantation. Formal EQ-5D/SF-36 data specific to ARVC populations are less commonly reported in the mainstream ARVC literature compared to more common cardiomyopathies; curators should search specifically for ARVC-focused QOL studies (e.g., studies of ICD recipients with ARVC) rather than assume generic cardiomyopathy QOL data applies uniformly.

4. Genetic/Molecular Information

Causal genes (desmosomal — "the big five"): - PKP2 (plakophilin-2) — HGNC:9024; most common - DSP (desmoplakin) — HGNC:3052 - DSG2 (desmoglein-2) — HGNC:3049 - DSC2 (desmocollin-2) — HGNC:3036 - JUP (plakoglobin/junction plakoglobin) — HGNC:6207

Non-desmosomal genes: - TMEM43 — HGNC:19073 - DES (desmin) — HGNC:2770 - TTN (titin) — HGNC:12403 - PLN (phospholamban) — HGNC:9091 - RYR2 (ryanodine receptor 2) — HGNC:10484 - FLNC (filamin C) — HGNC:3756 - LMNA — HGNC:6636 - CDH2 (N-cadherin) — HGNC:1759 - CTNNA3 (α-T-catenin) — HGNC:2510 - SCN5A — HGNC:10593 - TGFB3 — HGNC:11768

Variant classification and type. Pathogenic variants in PKP2 are predominantly truncating (nonsense, frameshift, canonical splice-site) loss-of-function variants, consistent with a haploinsufficiency mechanism, whereas DSG2, DSC2, and DSP more commonly harbor missense as well as truncating variants, and some act via dominant-negative mechanisms disrupting desmosome assembly. TMEM43 disease is dominated by a single recurrent founder missense variant (p.S358L) in the Newfoundland population. ACMG/AMP classification (pathogenic, likely pathogenic, VUS) should be verified per-variant in ClinVar/ClinGen, as classification is variant-specific.

Allele frequency. Pathogenic ARVC variants are individually rare in population databases (gnomAD), consistent with a rare Mendelian disease under purifying selection, though the PLN p.R14del variant shows a founder effect with elevated frequency in the Dutch/Netherlands population specifically.

Somatic vs. germline. ARVC-causing variants are germline; no significant somatic mosaicism literature specific to ARVC pathogenesis is well established (in contrast to some other inherited arrhythmia syndromes), though germline mosaicism in unaffected parents of de novo cases has been reported anecdotally.

Functional consequences. The dominant mechanistic model is haploinsufficiency/loss of desmosomal protein function leading to weakened intercalated disc mechanical coupling, though dominant-negative effects (particularly for missense variants disrupting protein-protein interaction domains) are also documented. A gain-of-function/dominant-negative mechanism is also implicated for some DSP variants causing the "hot phase" inflammatory presentation.

Modifier genes/factors. Digenic/compound heterozygosity across desmosomal genes is the best-documented genetic modifier of severity. TTN variants and other "second hits" have also been proposed as disease modifiers in some cohorts.

Epigenetic information. Specific well-characterized epigenetic (DNA methylation/histone) contributions to ARVC pathogenesis are not a major established pillar of the literature relative to the structural/desmosomal mechanism; curators should search ENCODE/Roadmap Epigenomics/DiseaseMeth specifically if this dimension is needed, as it is not a primary focus of current mechanistic literature.

Chromosomal abnormalities. ARVC is not typically caused by large-scale chromosomal abnormalities (aneuploidy, translocations); it is predominantly a single-gene/point-variant disease. No major DECIPHER-cataloged CNV syndrome is classically associated with ARVC as a primary feature.

5. Environmental Information

Environmental/lifestyle factors. As above, competitive and endurance exercise is the dominant, best-documented environmental modifier — it both unmasks/accelerates disease in genotype-positive individuals and is independently associated with an ARVC-like phenocopy in some non-genotyped athletes ("exercise-induced arrhythmogenic remodeling"), a concept debated in the literature (distinguishing true genetic ARVC from an acquired exercise-induced RV remodeling phenotype in endurance athletes is an active area of clinical and research interest).

Infectious agents. Not a primary etiological category for ARVC; however, myocarditis-like presentations (particularly in DSP-related disease, the "hot phase") can clinically mimic viral myocarditis and are sometimes triggered by or co-occur with viral infection, though this is a disease-manifestation overlap rather than an established infectious cause.

6. Mechanism / Pathophysiology

Causal chain overview. Desmosomal gene mutation → destabilized intercalated disc mechanical junctions → cardiomyocyte detachment/death under mechanical (especially exercise-induced) stress → myocardial injury and inflammatory response → replacement fibrosis and fibroadipogenesis (with displaced plakoglobin suppressing canonical Wnt/β-catenin signaling and promoting adipogenic/fibrogenic transcriptional programs, per Garcia-Gras et al. 2006, PMID:16467587) → disruption of gap junction (connexin-43) localization and reduced conduction velocity → re-entrant substrate for ventricular arrhythmia → progressive RV (and often LV) structural remodeling, dilation, and dysfunction → heart failure in advanced disease.

Molecular pathways: - Desmosome-intercalated disc mechanical coupling pathway (structural) - Wnt/β-catenin signaling — canonical pathway suppression via nuclear plakoglobin translocation (KEGG Wnt signaling pathway; GO term suggestion: GO:0060070 canonical Wnt signaling pathway, with a NEGATIVE modifier) - Gap junction remodeling — connexin-43 (GJA1) lateralization and reduced expression at intercalated discs, contributing to conduction slowing (Cx43-related literature is well established in ARVC mechanistic studies) - Calcium handling dysregulation — particularly relevant in RYR2-related and PLN-related forms, overlapping with catecholaminergic polymorphic VT mechanisms

Cellular processes: Apoptosis and/or necroptosis of cardiomyocytes under mechanical stress; adipogenic transdifferentiation of cardiac progenitor or resident mesenchymal populations; fibroblast activation and fibrosis (overlapping conceptually with the dismech fibrotic_response module pattern: tissue injury → inflammation → mesenchymal activation → myofibroblast → excessive ECM deposition); chronic low-grade inflammation, particularly pronounced in DSP-related "hot phase" disease with lymphocytic infiltration resembling myocarditis.

Protein dysfunction. Loss of normal desmosomal plaque assembly (PKP2, DSG2, DSC2, DSP, JUP proteins normally form a multiprotein complex linking cadherins to the intermediate filament cytoskeleton); structural destabilization reduces mechanical resilience of the intercalated disc under cyclic mechanical load.

Tissue damage mechanisms. Mechanical stress-induced myocyte injury (particularly at the RV free wall, which is thin-walled and mechanically vulnerable), followed by an inflammatory/reparative fibrofatty replacement process rather than typical ischemic necrosis.

Immune system involvement. Myocardial inflammatory infiltrates (lymphocytic myocarditis-like pattern) are documented, especially in DSP cardiomyopathy "hot phase" episodes; autoimmune/autoantibody mechanisms (e.g., anti-desmoglein-2 antibodies) have also been proposed in some studies as contributing to disease propagation, though this remains an area of ongoing investigation rather than settled mechanism.

Biochemical abnormalities. Reduced/mislocalized desmosomal protein expression at the intercalated disc (demonstrable by endomyocardial biopsy immunohistochemistry, e.g., reduced plakoglobin signal — a research/diagnostic tool explored by the Toronto/Padua groups); altered connexin-43 distribution.

Molecular profiling. Transcriptomic studies of ARVC myocardium (from explanted hearts) show upregulation of adipogenic and fibrogenic gene programs and downregulation of Wnt target genes; proteomic and single-cell/spatial transcriptomic characterization of ARVC myocardium is an active but still maturing area (search GEO, Human Cell Atlas heart datasets for current single-cell cardiomyocyte/fibroblast/adipocyte composition data in ARVC hearts).

GO/CL term suggestions: GO:0007163 (cell adhesion mediated by integrin — related but not exact; better: GO:0030057 desmosome), GO:0016337 (cell-cell adhesion), GO:0060070 (canonical Wnt signaling pathway), CL:0000746 (cardiac muscle cell / cardiomyocyte), CL:0000057 (fibroblast), CL:0000136 (adipocyte).

7. Anatomical Structures Affected

Organ level. Primary: right ventricle (RV), classically the "triangle of dysplasia" (RV inflow tract, outflow tract, and apex). Left ventricular involvement occurs in biventricular and left-dominant forms (notably DSP- and FLNC-related disease), which is now recognized as common enough to justify the broader "arrhythmogenic cardiomyopathy" nomenclature. Secondary involvement: heart failure sequelae affecting other organs in advanced disease (hepatic congestion, renal hypoperfusion).

• UBERON suggestions: UBERON:0002080 (heart right ventricle... actually UBERON:0002080 is "cardiac ventricle"; right ventricle-specific term is UBERON:0002080's child), UBERON:0015230 (myocardium of right ventricle) — curators should verify exact UBERON IDs via OAK lookup rather than trust from memory.

Tissue/cell level. Myocardium (cardiomyocytes, CL:0000746) undergoing progressive replacement by fibrous connective tissue (fibroblasts/myofibroblasts, CL:0000057) and adipose tissue (adipocytes, CL:0000136); the epicardial-to-endocardial gradient of fibrofatty infiltration is a classic histopathological feature.

Subcellular level. Intercalated disc (a specialized cell-cell junction complex); desmosome (GO:0030057, cellular component); gap junction (GO:0005921) — connexin-43 mislocalization from gap junctions is well documented.

Cutaneous involvement (syndromic forms). Skin (palms/soles — palmoplantar keratoderma) and hair follicles (woolly hair) in Naxos disease and, variably, Carvajal syndrome, reflecting the shared desmosomal biology between cardiac intercalated discs and epidermal desmosomes.

Localization/laterality. RV-predominant in classic ARVC; biventricular or LV-dominant in DSP/FLNC-related disease; regional patchy involvement (not diffuse) is characteristic, contributing to the classic "epicardial to endocardial," patchy wavefront pattern of fibrofatty replacement.

8. Temporal Development

Onset. Typically manifests in adolescence through middle adulthood (most commonly 20s-40s); pediatric-onset and elderly-onset presentations are less common but reported. Onset is often insidious, with a "concealed phase" preceding overt clinical manifestation.

Progression — the classic four-phase natural history model (Thiene/Basso/Corrado, Padua group, foundational literature): 1. Concealed phase — subtle or absent structural abnormalities; SCD (often exercise-related) may be the first and only manifestation in this phase, particularly in young athletes. 2. Overt electrical disorder phase — symptomatic ventricular arrhythmias with clear structural RV abnormalities. 3. Right ventricular failure phase — progressive RV pump failure with preserved LV function. 4. Biventricular pump failure phase — end-stage disease with both ventricles failing, potentially indistinguishable from dilated cardiomyopathy.

Progression rate and course. Variable — generally slowly progressive over years to decades, but genotype (e.g., TMEM43, compound/digenic desmosomal variants), sex (male), and exercise exposure accelerate progression. Disease course is chronic and lifelong; spontaneous remission does not occur, though disease activity (especially inflammatory "hot phase" episodes in DSP disease) can fluctuate episodically.

Critical periods. Adolescence/young adulthood during competitive sports participation represents a key window of vulnerability, both because arrhythmic risk peaks around this exercise-intensive period and because this is when many genotype-positive individuals first become symptomatic or are identified via family cascade screening.

9. Inheritance and Population

Epidemiology. Estimated prevalence commonly cited in the literature is approximately 1 in 1,000 to 1 in 5,000 in the general population, though this figure is imprecise and varies by region and case ascertainment methodology; higher prevalence is reported in some endemic regions (e.g., the Veneto region of Italy, where the disease was first extensively characterized). ARVC is disproportionately represented among cases of SCD in young athletes in certain series (notably Italian autopsy-based athlete SCD studies from the Padua group), though the exact proportion varies by cohort and geography (US series generally attribute a smaller proportion of athlete SCD to ARVC compared to Italian series, a well-known geographic discrepancy in the literature).

Inheritance pattern. Predominantly autosomal dominant (most desmosomal gene forms); autosomal recessive in Naxos disease (JUP) and Carvajal syndrome (DSP), both associated with cardiocutaneous phenotypes.

Penetrance. Incomplete and age-related — penetrance increases with age, and is generally higher in males than females for most genotypes; PKP2 penetrance in particular is well documented as incomplete, meaning many genotype-positive family members remain asymptomatic or subclinical for years.

Expressivity. Highly variable, even within families carrying the identical pathogenic variant — a hallmark feature that has generated substantial modifier-gene and gene-environment interaction research (as above).

Genetic anticipation. Not a well-established feature of ARVC (unlike repeat-expansion disorders); not typically discussed in the mainstream literature.

Founder effects. TMEM43 p.S358L in the Newfoundland (Canada) population is the best-documented founder variant, associated with a highly penetrant, malignant phenotype particularly in males; PLN p.R14del founder variant in the Netherlands is associated with both ACM and DCM phenotypes.

Consanguinity role. Relevant specifically to the autosomal recessive forms (Naxos disease, first described in families from the Greek island of Naxos with elevated consanguinity; Carvajal syndrome, initially described in Ecuadorian families).

Sex ratio. Male predominance in symptomatic/clinically overt disease is well documented across most genetic subtypes, generally cited in the range of roughly 3:1 to 2:1 male:female in clinically ascertained cohorts, though exact ratios vary by study and genotype.

Geographic distribution. Well characterized as endemic/over-represented in the Veneto region of Italy (site of the foundational Padua-group pathological studies); Naxos disease geographically clustered on the Greek island of Naxos and other Greek islands; TMEM43 founder variant concentrated in Newfoundland, Canada.

10. Diagnostics

Diagnostic framework. Diagnosis is guided by the 2010 Task Force Criteria (TFC) (revised from the original 1994 criteria), which integrate six categories of evidence, each with major and minor criteria: (1) global/regional RV dysfunction and structural alterations (echocardiography, MRI, RV angiography); (2) tissue characterization (endomyocardial biopsy histology); (3) repolarization abnormalities (ECG T-wave inversion); (4) depolarization/conduction abnormalities (epsilon waves, prolonged terminal activation duration on signal-averaged ECG); (5) arrhythmias (VT with LBBB morphology, PVC burden); (6) family history/genetics. Diagnostic categories are combined into definite, borderline, or possible diagnosis based on point totals.

Imaging. - Cardiac MRI — gold-standard imaging modality, assessing RV/LV volumes, function, regional wall motion abnormalities, and late gadolinium enhancement (fibrofatty tissue characterization). - Echocardiography — first-line screening, assessing RV size/function and regional wall motion abnormalities. - RV angiography — historically used, now largely supplanted by MRI.

Electrophysiology. - 12-lead ECG — T-wave inversion in right precordial leads, epsilon waves, prolonged terminal activation duration. - Signal-averaged ECG (SAECG) — detects late potentials reflecting delayed, fragmented conduction in diseased myocardium. - Holter monitoring / exercise stress testing — quantifies PVC burden and detects exercise-induced ventricular arrhythmia. - Electroanatomic voltage mapping — identifies low-voltage scar regions corresponding to fibrofatty replacement, used both diagnostically and to guide ablation.

Biopsy/histopathology. Endomyocardial biopsy showing fibrofatty replacement of myocardium is a major Task Force criterion when quantitative histomorphometric thresholds are met, though biopsy has significant sampling-error limitations given the patchy, often epicardial-predominant nature of disease.

Genetic testing. - Recommended approach: targeted next-generation sequencing gene panels covering the desmosomal genes (PKP2, DSP, DSG2, DSC2, JUP) plus non-desmosomal genes (TMEM43, DES, TTN, PLN, RYR2, FLNC, LMNA, CDH2, CTNNA3) are standard first-line testing in patients meeting clinical Task Force criteria. - Single-gene testing may be appropriate for known familial variants (cascade testing). - Whole exome/genome sequencing is increasingly used, particularly in genotype-negative "definite" clinical cases or atypical presentations, to identify novel/non-canonical genes. - Chromosomal microarray, karyotyping, FISH, and mitochondrial DNA testing are not standard components of ARVC diagnostic workup given the single-gene point-variant nature of the disease.

Clinical criteria/differential diagnosis. Key differentials include idiopathic RV outflow tract VT (structurally normal heart, a benign arrhythmia that must be distinguished from early ARVC), sarcoidosis (can mimic ARVC with RV involvement and VT — "arrhythmogenic mimics" is a recognized diagnostic challenge), dilated cardiomyopathy (in advanced/biventricular ARVC), Brugada syndrome (some genetic and phenotypic overlap, particularly SCN5A-related cases), congenital heart disease with RV volume overload, and athletic RV remodeling ("athlete's heart").

Screening. Cascade genetic and clinical (ECG + echocardiography, ideally with periodic reassessment given age-related penetrance) screening of first-degree relatives of an affected proband is standard of care once a pathogenic variant is identified in an index case.

11. Outcome/Prognosis

Survival/mortality. With modern management (ICD therapy, exercise restriction, pharmacotherapy, ablation), annual mortality rates in genotype-positive/diagnosed cohorts have decreased substantially compared to historical (pre-ICD-era) cohorts, though ARVC remains an important cause of SCD in the young. Risk stratification for primary/secondary prevention ICD implantation is central to prognosis, incorporating factors such as prior sustained VT/VF, extensive RV/LV dysfunction, non-sustained VT burden, syncope, and genotype (e.g., multiple/compound desmosomal variants, TMEM43 founder variant carriers).

Morbidity. ICD-related morbidity (inappropriate shocks, lead complications, psychological burden) is a significant component of disease burden in this population; progression to heart failure requiring advanced therapies (including heart transplantation) occurs in a subset of patients, particularly those with the biventricular/burnt-out phenotype.

Complications. Ventricular arrhythmia/SCD, heart failure, and (in DSP "hot phase" disease) recurrent acute myocarditis-like episodes with troponin elevation and chest pain are the principal disease-specific complications.

Prognostic factors/biomarkers. Established clinical risk factors used in contemporary multivariable risk calculators (e.g., the ARVC risk calculator developed by the Johns Hopkins/multi-center collaboration) include: prior sustained ventricular arrhythmia, syncope, non-sustained VT, PVC burden, T-wave inversion extent, RV/LV ejection fraction, male sex, and proband status. Biomarker-based prognostication (e.g., natriuretic peptides, troponin during hot-phase episodes) is used adjunctively but is not a primary risk-stratification pillar comparable to the clinical/imaging/electrical factors above.

12. Treatment

Pharmacotherapy. - Beta-blockers — first-line antiarrhythmic and symptom-management therapy (NCIT term suggestion: NCIT:C15986 Pharmacotherapy; therapeutic_agent class NCIT:C2949 or specific beta-blocker CHEBI terms as appropriate). - Antiarrhythmic drugs — sotalol has historically been the most studied agent for ARVC-related VT suppression; amiodarone is also used, particularly in combination with beta-blockade or when sotalol is inadequate/contraindicated. - Heart failure pharmacotherapy (ACE inhibitors/ARBs, mineralocorticoid receptor antagonists, diuretics) in patients with RV or biventricular dysfunction/failure.

Interventional/device therapy. - Implantable cardioverter-defibrillator (ICD) — cornerstone of SCD prevention in high-risk patients (both primary and secondary prevention indications), guided by risk-stratification algorithms as above. - Catheter ablation (radiofrequency, endocardial and epicardial) — used for recurrent VT refractory to or as an adjunct to antiarrhythmic drugs and ICD therapy; epicardial ablation is particularly relevant given the epicardial-predominant nature of the arrhythmogenic substrate in many patients.

Surgical/advanced therapy. - Heart transplantation — reserved for end-stage biventricular heart failure refractory to medical/device therapy.

Supportive/behavioral. - Exercise restriction — a cornerstone, non-pharmacological management recommendation for genotype-positive individuals (both affected and at-risk asymptomatic carriers), given the strong exercise-disease progression relationship (NCIT term suggestion: NCIT:C181743 Behavioral Counseling, or a lifestyle-modification-specific term).

Experimental/emerging therapies. Active research areas include gene therapy approaches targeting specific desmosomal deficiencies (preclinical), small molecules targeting the Wnt/β-catenin pathway (e.g., SB216763, a GSK-3β inhibitor shown to rescue the ARVC phenotype in preclinical plakoglobin-deficient mouse models, per the Garcia-Gras et al. line of mechanistic work), and anti-inflammatory approaches for DSP "hot phase" disease; curators should search ClinicalTrials.gov directly for current NCT-registered trials, as this space evolves rapidly.

Treatment strategy. Management follows a risk-stratified algorithm: exercise restriction and beta-blockade for all affected/genotype-positive individuals; ICD implantation guided by validated risk calculators; antiarrhythmic drugs and/or catheter ablation for breakthrough arrhythmia; advanced heart failure therapy/transplantation for end-stage disease.

13. Prevention

Primary prevention. Not applicable in the traditional infectious-disease sense (this is a genetic disease), but pre-symptomatic identification via cascade genetic testing of relatives, combined with exercise restriction in genotype-positive individuals, functions as a primary preventive strategy against disease acceleration and first arrhythmic event.

Secondary prevention. Periodic clinical screening (ECG, echocardiography, and as appropriate cardiac MRI) of genotype-positive but phenotype-negative relatives, given age-related penetrance, to detect early disease before major arrhythmic events occur; participation in pre-participation athletic screening programs (notably the Italian model, which screens competitive athletes with ECG as part of a broader SCD-prevention strategy) has been credited with reduced ARVC-related athlete mortality in some studies from the Padua group, though this remains a subject of ongoing health-policy debate, particularly regarding cost-effectiveness and false-positive rates in other health systems (e.g., the US).

Tertiary prevention. ICD therapy and antiarrhythmic management to prevent SCD and disease complications in already-diagnosed patients; heart failure management to prevent/delay progression to transplantation.

Genetic counseling. Central to ARVC management given autosomal dominant inheritance with incomplete penetrance — counseling addresses recurrence risk, the rationale and limitations of cascade testing, reproductive options, and the psychological/lifestyle implications (particularly exercise restriction) of a positive genotype.

Public health / sports cardiology screening. Pre-participation cardiovascular screening programs for competitive athletes (protocols vary substantially by country/sporting body) represent the primary public-health-level intervention relevant to ARVC-related SCD prevention.

14. Other Species / Natural Disease

Boxer dogs are a well-recognized, naturally occurring large-animal model of arrhythmogenic right ventricular cardiomyopathy, historically termed "Boxer ARVC" — this is one of the best-characterized spontaneous veterinary parallels to the human disease, associated with a striatin (STRN) gene variant in some studied populations (search OMIA for the precise, current gene association, as this has been refined over time in the veterinary genetics literature). Naturally occurring ARVC-like disease has also been described in cats. These represent genuine spontaneous/naturally occurring veterinary disease rather than induced laboratory models, and are cataloged in OMIA (Online Mendelian Inheritance in Animals).

Comparative biology. The desmosomal cell-adhesion machinery is highly evolutionarily conserved across mammals, supporting good face-validity of both spontaneous animal disease and engineered rodent models for mechanistic study.

15. Model Organisms

Mouse models. - Heterozygous plakoglobin (Jup)-deficient mice — the foundational genetic mouse model (Garcia-Gras et al., PMID:16467587) demonstrating that Jup haploinsufficiency, combined with exercise (endurance training), produces the classic ARVC phenotype (RV dilation, fibrofatty replacement, arrhythmia), and that Wnt pathway restoration (via GSK-3β inhibition) rescues the phenotype — directly connecting mechanism to a therapeutic hypothesis. Kirchhof et al. (PMID:16769908) further characterized exercise-dependent electrophysiological remodeling in this model. - Desmoplakin (Dsp) cardiac-restricted knockout/mutant mice — recapitulate fibrofatty replacement, arrhythmia, and (in some models) the inflammatory "hot phase" phenotype relevant to human DSP cardiomyopathy. - PKP2 cardiomyocyte-specific knockout mice — used to study PKP2 haploinsufficiency/loss-of-function mechanisms, including roles in calcium handling and gap junction remodeling beyond pure mechanical coupling. - TMEM43 p.S358L knock-in mice — model the highly penetrant Newfoundland founder variant phenotype.

Zebrafish models. Used for select desmosomal and non-desmosomal gene studies given rapid generation time and amenability to genetic/chemical screening, though less extensively deployed for ARVC specifically compared to mouse models.

iPSC-derived cardiomyocyte models. Patient-derived and CRISPR-engineered induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) carrying desmosomal (PKP2, DSP, DSG2) and non-desmosomal (PLN, FLNC) pathogenic variants are widely used to model cell-autonomous phenotypes including abnormal desmosome assembly, adipogenic differentiation propensity, altered calcium handling, and arrhythmic electrophysiological phenotypes in vitro — an increasingly central platform for both mechanistic study and drug screening given the difficulty of studying the "second hit" of mechanical stress in a dish.

Model characteristics/limitations. Mouse models generally require an exercise or additional genetic "second hit" (e.g., combined with a second desmosomal mutation) to fully recapitulate the human phenotype, reflecting the multifactorial (genetic + mechanical stress) nature of human disease — a single heterozygous desmosomal mutation alone is often insufficient to produce a fully penetrant phenotype in mice at baseline, mirroring the incomplete penetrance seen in human carriers. iPSC-CM models, while excellent for cell-autonomous mechanism, cannot easily recapitulate the whole-organ mechanical stress, fibrosis, and in vivo arrhythmia substrate that define the clinical disease — an important human-model-fidelity caveat relevant to any hypothesis built primarily on iPSC-CM data (analogous to the HUMAN_MODEL_MISMATCH framing used in dismech curation for other diseases).

Resources. MGI (Mouse Genome Informatics) for mouse allele records (Jup, Dsp, Pkp2, Tmem43 knockout/knock-in strains); IMPC/KOMP for systematic knockout phenotyping data; ZFIN for zebrafish; Alliance of Genome Resources for cross-species orthology (e.g., confirming PKP2/DSP/JUP ortholog conservation across mouse, zebrafish, and human).

Citation Summary and Confidence Notes

This report draws on the well-established ARVC/ACM literature as understood through my training. High-confidence, specifically citable claims include the Garcia-Gras et al. 2006 (PMID:16467587) plakoglobin/Wnt mechanism paper and the Kirchhof et al. 2006 (PMID:16769908) exercise-mouse-model paper. Gene lists (PKP2, DSP, DSG2, DSC2, JUP, TMEM43, DES, TTN, PLN, RYR2, FLNC, LMNA, CDH2, CTNNA3, SCN5A, TGFB3), the 2010 Task Force Criteria framework, the four-phase natural history model (Thiene/Basso/Corrado, Padua group), Naxos disease and Carvajal syndrome as recessive cardiocutaneous variants, TMEM43 Newfoundland founder effect, PLN p.R14del Dutch founder effect, and Boxer dog ARVC as a natural veterinary model are all well-established facts in the cardiovascular genetics literature that I am highly confident in, though I was not able to run live PubMed/OMIM/Orphanet/HPO/gnomAD/ClinVar queries in this session to pull exact current PMIDs, precise OMIM/Orphanet/MONDO/HPO numeric IDs, or up-to-date prevalence/frequency statistics.

Important curation caveat: Several specific identifiers in this report (OMIM subtype numbers, the MONDO ID, exact HPO term IDs, precise UBERON IDs, and quantitative frequency/prevalence figures) should be independently verified via OAK/runoak lookups and live database queries (OMIM, Orphanet, ClinVar, gnomAD, HPO) before being committed to a dismech KB entry — consistent with the project's anti-hallucination SOP (§2, §2a of the dismech evidence guidelines) requiring that every PMID, snippet, and ontology term be independently verified against its primary source rather than trusted from a synthesized report. I was not able to perform that live verification in this session, so this report should be treated as a curation lead requiring the standard just fetch-reference / just validate-terms verification workflow, not as pre-verified ground truth.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Comprehensive Disease Characteristics Report

Disease: Arrhythmogenic right ventricular cardiomyopathy (ARVC / arrhythmogenic cardiomyopathy, ACM) MONDO ID: MONDO:0016587 Category: Mendelian (inherited cardiomyopathy) Report basis: 20 confirmed findings, 66 papers reviewed across 5 investigation iterations

Summary

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited, mostly autosomal-dominant cardiomyopathy of the cardiac desmosome. Pathogenic variants in genes encoding intercalated-disc adhesion proteins impair cardiomyocyte cell–cell adhesion, so that mechanical stress — critically accelerated by endurance exercise — drives progressive myocyte death and fibrofatty replacement of the myocardium. The result is a substrate for life-threatening ventricular arrhythmias, sudden cardiac death (SCD) in the young, and, over time, progressive biventricular heart failure. The most common causal gene is PKP2 (plakophilin-2, ~40% of cases); other established genes are DSP, DSG2, DSC2, JUP (desmosomal) and TMEM43, PLN, DES, FLNC, LMNA, TTN (non-desmosomal). A pathogenic variant is identified in only ~50% of probands, and the disease shows incomplete, age-dependent penetrance and striking variable expressivity even within families.

Mechanistically, loss of desmosomal integrity releases plakoglobin, which suppresses canonical Wnt/β-catenin signaling; the Hippo pathway is activated; and PPARγ/TGF-β programs reprogram cardiac cells toward adipogenic and fibrotic fates. In parallel — and often preceding overt structural change — gap-junction (connexin-43) and sodium-channel (NaV1.5) remodeling at the intercalated disc slows conduction and creates the arrhythmic substrate. Modern single-cell, spatial, and proteomic profiling has refined this picture, revealing expanded fibroblast/adipocyte populations, disease-associated cardiomyocyte states, and NLRP3/CCL3-driven inflammation, and nominating circulating biomarkers (CCL3, UCHL1, OCIAD1, desmoyokin, ZBTB11).

Diagnosis relies on the 2010 Revised Task Force Criteria (supplemented by 2020 Padua criteria) integrating ECG, imaging (echocardiography and cardiac MRI with late gadolinium enhancement), tissue characterization, arrhythmia burden, and family/genetic data — and must be distinguished from multiple phenocopies. Management is not curative and rests on exercise restriction, beta-blockers/antiarrhythmic drugs, catheter ablation, and — the only intervention proven to prevent SCD — the implantable cardioverter-defibrillator (ICD), guided by the validated ARVC risk calculator (arrhythmia) and biventricular dysfunction (death/transplant; HR 6.3). Disease-modifying AAV gene therapies (AAV9:PKP2 replacement; mutation-agnostic AAV-Cx43) have been validated in animal models and are entering clinical translation. ARVC also occurs naturally in Boxer dogs (striatin deletion) and is modeled in Jup/Dsp/Pkp2/Tmem43 mice and patient-derived iPSC cardiomyocytes.

Key Findings

1. ARVC is primarily a genetic disease of the cardiac desmosome (F001)

ARVC is fundamentally a disease of impaired cardiomyocyte cell–cell adhesion. In the largest ARVC registries, pathogenic variants in desmosomal genes are found in roughly half to two-thirds of probands. The five classic desmosomal genes are PKP2 (plakophilin-2, the most common), DSP (desmoplakin), DSG2 (desmoglein-2), DSC2 (desmocollin-2), and JUP (plakoglobin/γ-catenin). Non-desmosomal genes contributing to the arrhythmogenic-cardiomyopathy spectrum include TMEM43, PLN, DES, TTN, FLNC, and LMNA. In a pediatric ARVC cohort, a pathogenic desmosomal mutation was detected in 87% of patients.

"Arrhythmogenic cardiomyopathy (ACM) is a fatal genetic heart disease primarily caused by mutations in desmosomal genes, leading to impaired cell-cell adhesion, ventricular arrhythmias, and progressive heart failure." — PMID: 41582809

"Pathogenic mutation in desmosomal genes was detected in 87%." — PMID: 41078126

Ontology suggestions: HGNC genes PKP2, DSP, DSG2, DSC2, JUP, TMEM43, PLN, DES, FLNC, LMNA; GO:0007156 (homophilic cell adhesion via plasma-membrane adhesion molecules); GO:0002159 (desmosome assembly); GO:0005911 (cell–cell junction / intercalated disc).

2. Suppressed Wnt/β-catenin and activated Hippo signaling drive fibro-adipogenesis (F002)

The central molecular consequence of desmosomal disruption is signaling dysregulation. Loss of desmosomal integrity releases plakoglobin (γ-catenin), which competes with β-catenin and suppresses canonical Wnt signaling. The Hippo pathway is activated (phosphorylation of MST1/2, LATS1/2, and YAP). Together these converge to reprogram cardiac progenitors and myocytes toward adipogenic (PPARγ upregulation) and fibrotic fates. A common, mutation-agnostic alteration is reduced connexin-43 (Cx43) gap-junction expression.

"Altered protein constituents of intercalated discs were associated with activation of the upstream Hippo molecules" — PMID: 24276085

"The reduction in expression of the ventricular gap junction protein Cx43 (connexin-43) is a common molecular alteration underlying desmosomal junctional deficits and arrhythmias" — PMID: 41582809

Ontology suggestions: GO:0060070 (canonical Wnt signaling pathway); GO:0035329 (Hippo signaling); GO:0050873 (brown fat cell differentiation); GO:0005922 (connexin complex).

3. ARVC is a leading cause of SCD in young athletes; exercise accelerates the phenotype (F003)

ARVC is one of the most important causes of sudden death in young athletes, and physical activity is a genuine disease accelerator rather than a mere trigger. In a four-decade juvenile SCD registry from north-east Italy, ACM was the cause of SCD in 29% of competitive athletes. Intense endurance exercise accelerates phenotypic expression and arrhythmic propensity, with the strongest evidence for PKP2-mediated ACM, supported by both desmoplakin-transgenic mouse and human data. Preparticipation ECG screening reduced athlete SCD incidence in Italy (from 0.43 to 0.14 per 100,000/year after 2010).

"ACM was the cause of SCD in 29% of athletes." — PMID: 42305082

"the evidence that exercise is a disease-accelerator is most compelling for PKP2-mediated ACM" — PMID: 41954551

Ontology suggestions: HP:0001645 (Sudden cardiac death); HP:0004308 (Ventricular arrhythmia).

4. Management: exercise restriction, antiarrhythmics, ablation, and ICD (F004)

No curative therapy exists. Management combines: (1) exercise restriction; (2) beta-blockers and antiarrhythmic drugs, which reduce arrhythmia burden but not SCD risk; (3) catheter ablation of VT — endocardial ablation alone has high recurrence because of the epicardial and patchy substrate, so combined endo-epicardial ablation improves success; and (4) ICD implantation for high-risk patients after risk stratification. Bilateral cardiac sympathetic denervation reduced ICD shocks in refractory VT (5 of 8 patients VT-free).

"Treatment consists of restriction of physical exercise, antiarrhythmic drugs, catheter ablation and ICD implantation." — PMID: 25894016

"Antiarrhythmic drugs play an important role in terms of reduction of both the number and the complexity of arrhythmias, but they do not reduce the risk of SD." — PMID: 25894016

"Endocardial VT ablation in this setting can produce acute success, though recurrence rate is quite high, which may be explained by the more epicardial and patchy nature of the disease." — PMID: 28779285

Ontology suggestions (NCIT): ICD implantation, catheter ablation, beta-adrenergic blocker therapy, sotalol, amiodarone.

5. Epidemiology: prevalence ~1 in 2,000–5,000, male predominance, 2nd–4th-decade onset (F005)

Estimated prevalence is 1 in 5,000 to 1 in 2,000 in the general population. The disease affects men more frequently than women and typically becomes clinically overt from the second to the fourth decade of life. In athlete SCD registries, cases are overwhelmingly male (e.g., 50 of 51 in one Italian series).

"a genetically determined rare cardiomyopathy (1 in 5000 to 1 in 2000 in the general population)" — PMID: 25894016

"The disease affects men more frequently than women and becomes clinically overt usually from the second to the fourth decade of life." — PMID: 25894016

6. A validated multivariable risk calculator predicts incident ventricular arrhythmia (F006)

A validated calculator (www.ARVCrisk.com) estimates individualized risk of first-time sustained ventricular arrhythmia (VA) in definite ARVC patients and performs well (C-statistic ~0.78). Incremental predictors under study include RV free-wall longitudinal strain/regional deformation (raising the C-statistic to ~0.82) and LV late gadolinium enhancement on CMR. Circulating miRNAs (miR-15a-5p, miR-16-5p, miR-92a-3p) show promise for risk stratification.

"A risk calculator for individualized prediction of first-time sustained ventricular arrhythmia (VA) in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients has recently been developed and validated (www.ARVCrisk.com)." — PMID: 37474315

"The arrhythmogenic right ventricular cardiomyopathy (ARVC) risk calculator estimates the risk of incident sustained ventricular arrhythmia (VA) and performs well..." — PMID: 41608798

7. Recessive cardiocutaneous syndromes link ARVC to skin/hair phenotypes (F007)

Two autosomal-recessive cardiocutaneous syndromes anchored the discovery of desmosomal ARVC genetics. Naxos disease (OMIM 601214) is recessive ARVC caused by a homozygous JUP (plakoglobin) mutation, with woolly hair (from birth), palmoplantar keratoderma (first year), and cardiomyopathy manifesting by adolescence with 100% penetrance. Carvajal syndrome (OMIM 605676) is caused by DSP mutations with predominantly left-ventricular involvement and childhood-onset heart failure; recessive DSC2 mutations produce an overlapping phenotype.

"Naxos disease is a recessively inherited condition with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and a cutaneous phenotype, characterised by peculiar woolly hair and palmoplantar keratoderma." — PMID: 16722579

"Defects in the linking sites of these proteins can interrupt the contiguous chain of cell adhesion, particularly under conditions of increased mechanical stress or stretch, leading to cell death, progressive loss of myocardium and fibro-fatty replacement." — PMID: 16722579

"Carvajal syndrome (Online Mendelian Inheritance in Man [OMIM] 605676) is characterized by the association of dilated cardiomyopathy, striate palmoplantar keratoderma, and woolly hair." — PMID: 25824144

Ontology suggestions: HP:0007502 (Woolly hair); HP:0000982 (Palmoplantar keratoderma).

8. Autosomal-dominant inheritance with incomplete penetrance and variable expressivity (F008)

A familial history is present in 30–50% of cases. ARVC is usually inherited in an autosomal-dominant pattern with variable penetrance and expressivity, plus recessive forms (Naxos, Carvajal). Genetic testing finds a pathogenic mutation in only ~50% of patients (gene-elusive in the remainder). Wide intra- and inter-family expressivity remains largely unexplained. The recognized disease spectrum now includes right-dominant (ARVC), left-dominant (ALVC), and biventricular arrhythmogenic cardiomyopathy.

"A familial history of ARVC is present in 30% to 50% of cases, and the disease is considered a genetic cardiomyopathy, usually inherited in an autosomal dominant pattern with variable penetrance and expressivity" — PMID: 25548613

"Genetic testing is critical in identifying familial mutations and initiating cascade testing, but finds a pathogenic mutation in only ∼50% of patients." — PMID: 30446243

9. Naturally occurring ARVC in Boxer dogs (striatin deletion) (F009)

Boxer ARVC is a naturally occurring canine disease causing sudden death or heart failure, associated with a striatin (STRN) deletion. In a prospective study of 72 dogs (49 ARVC, 23 controls), ARVC was defined as ≥300 ventricular premature complexes/24h; 33% were syncopal, median age of diagnosis was 6 years, and 36 of 43 genotyped ARVC dogs carried the striatin deletion. It is a disease of middle age. Cats and other species also develop analogous disease.

"Boxer arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease that may result in sudden death or heart failure." — PMID: 24962663

Ontology suggestions: NCBITaxon:9615 (Canis lupus familiaris); STRN ortholog.

10. TMEM43 p.S358L causes the most aggressive subtype (ARVC5) via increased nuclear stiffness (F010)

ARVC-5 is the most aggressive heterozygous form, caused by the fully penetrant non-desmosomal TMEM43 p.S358L mutation, originally endemic to Newfoundland but shown by haplotype analysis to be a European founder mutation ~1,300–1,500 years old. In 62 Spanish carriers, SCD incidence was 38.7% (higher in men); left-ventricular involvement was common (40% with LVEF <50%). Mechanistically, carrier fibroblast nuclei show increased stiffness versus wild-type by atomic force microscopy.

"Arrhythmogenic right ventricular cardiomyopathy type V (ARVC-5) is the most aggressive heterozygous form of ARVC. It is predominantly caused by a fully penetrant mutation (p.S358L) in the nondesmosomal gene TMEM43-endemic to Newfoundland, Canada." — PMID: 32062046

"revealed that the cell nuclei exhibit an increased stiffness compared with TMEM43 wild-type controls" — PMID: 24598986

"The affected individuals showed a 38.7% incidence of sudden cardiac death, which was higher in men." — PMID: 32062046

11. Diagnosis requires distinguishing multiple phenocopies; electrical change precedes structural change (F011)

Diagnosis uses the 2010 Task Force Criteria (major/minor across ECG depolarization/repolarization, arrhythmias, imaging structural/functional, tissue characterization, and family/genetics). Differential diagnoses include idiopathic RV outflow-tract tachycardia, Brugada syndrome, athlete's heart, dilated cardiomyopathy, myocarditis, cardiac sarcoidosis (a phenocopy that can produce epsilon waves), and congenital RV aneurysms. Electrical alterations (PVCs, VT/VF, T-wave inversions V1–V3, epsilon waves) frequently precede detectable structural changes. Three subtypes are recognized: right-dominant (classic ARVC), biventricular, and left-dominant (ALVC).

"Idiopathic RV outflow tract tachycardia, Brugada Syndrome, athlete's heart, dilated cardiomyopathy, myocarditis, cardiac sarcoidosis, congenital aneurysms and diverticula may mimic clinical phenotypes of ARVC." — PMID: 35268321

"structural findings often become visible after electrical alterations, such as premature ventricular beats, ventricular fibrillation (VF) and ventricular tachycardia (VT)" — PMID: 27617087

Ontology suggestions: HP:0011663 (Right ventricular cardiomyopathy); HP:0004756 (Ventricular arrhythmia).

12. Desmosomal dysfunction remodels gap junctions and sodium channels, creating the arrhythmic substrate (F012)

Immunohistochemistry of ACM patient hearts shows altered expression and distribution of connexin-43 (Cx43), plakoglobin, and the cardiac sodium channel NaV1.5 at the intercalated disc, secondary to desmosomal dysfunction. Reduced Cx43 and mislocalized/reduced NaV1.5 slow conduction and reduce sodium current, promoting reentry independent of — and preceding — overt fibrofatty structural change. This provides the mechanistic basis for the clinical observation that electrical abnormalities precede structural ones.

"a disturbed distribution of gap junction proteins and cardiac sodium channels may also be observed in AC phenotypes, secondary to desmosomal dysfunction" — PMID: 23834686

"The altered expression and/or distribution of NaV1.5 channels in AC hearts may play a mechanistic role in the arrhythmias leading to sudden cardiac death in AC patients." — PMID: 23834686

Ontology suggestions: genes SCN5A (NaV1.5), GJA1 (Cx43); GO:0086010 (membrane depolarization during action potential).

13. Inflammation and innate/autoimmunity contribute to "hot phase" episodes, especially in DSP carriers (F013)

A subset of ARVC patients experience "hot phases": chest pain with troponin release and ECG changes without ischemia, mimicking acute myocarditis. DSP (desmoplakin) variants are most frequently associated. Evidence implicates inflammation, autoimmunity, and innate immune activation — myocardial inflammatory infiltrates, circulating anti-desmosomal/anti-intercalated-disc autoantibodies, and NLRP3-inflammasome activation. Immunosuppressive therapy may modulate arrhythmic and heart-failure outcomes in DSP carriers.

"Growing data indicate that inflammation, autoimmunity, and innate immune activation play a central role in HP expression and ACM pathobiology, supported by findings of myocardial inflammatory infiltrates, circulating anti-desmosomal and anti-intercalated disc autoantibodies, and activation of NLRP3-inflammasome pathways." — PMID: 41448261

"Among ACM-related genes, desmoplakin (DSP) variants are most frequently associated with HP" — PMID: 41448261

Ontology suggestions: GO:0072559 (NLRP3 inflammasome complex); HP:0012819 (Myocarditis); CL:0000235 (macrophage).

14. DSP arrhythmogenic cardiomyopathy is a distinct left-dominant/biventricular entity (F014)

DSP-ACM is associated with more frequent LV involvement, lower LVEF (46±12% vs 56±10% in LV+ right-dominant ACM, P=0.001), LV late gadolinium enhancement, and inflammatory episodes. In families ascertained through acute myocarditis, DSP variants predominated; 39% of carriers had an arrhythmogenic LV phenotype, and 38% of asymptomatic carriers showed isolated LV LGE without meeting RV Task Force Criteria. Such patients often do NOT meet classic (RV-focused) 2010 Task Force Criteria — a key diagnostic pitfall.

"Arrhythmogenic cardiomyopathy (ACM) related to Desmoplakin (DSP) mutations is a distinct condition associated with particularly severe outcomes, more frequent left ventricular (LV) involvement, including fibrosis, dysfunction, and inflammatory episodes." — PMID: 40021092

"a remarkable phenotype of isolated LV late gadolinium enhancement on contrast-enhanced cardiac magnetic resonance without any other structural abnormality was found in 38% of asymptomatic mutation carriers" — PMID: 32356610

15. Biventricular dysfunction is the strongest predictor of death/transplant (F015)

In a 10-year registry of 96 ARVC patients (68% male, 35±15 yr), 21% experienced cardiac death or heart transplantation over 128±92 months. Independent predictors of death/HTx were RV dysfunction (HR 4.12, 95% CI 1.01–18.0, P=0.05), significant tricuspid regurgitation (HR 7.6, 95% CI 2.6–22.0, P<0.001), and amiodarone treatment (HR 3.4). Combined RV+LV ("ordinal") dysfunction was the strongest independent predictor (HR 6.3, 95% CI 2.17–17.45, P<0.001). RV systolic dysfunction was present in 65%, LV dysfunction in 24%.

"the 'ordinal dysfunction' (Model 2), which considers the presence of both RV and LV dysfunctions, this variable emerged as an independent prognostic predictor (HR: 6.3; 95% CI: 2.17-17.45; P < 0.001)" — PMID: 21362707

"During a mean follow-up of 128 ± 92 months, 20 patients (21%) experienced cardiac death or underwent HTx." — PMID: 21362707

16. AAV-mediated PKP2 gene replacement prevents and rescues ARVC in mice (F016)

PKP2 mutations account for ~40% of ARVC and cause reduced gene expression (haploinsufficiency), providing a strong rationale for gene replacement. Three independent groups showed AAV9:PKP2 gene delivery restores desmosomal/gap-junction structure, prevents or reverses RV dilation, improves LVEF, reduces ventricular arrhythmias and fibrosis, and extends survival (up to 100% survival in treated mice) — both prophylactically (neonatal) and after overt cardiomyopathy (PMID: 39196150; 38499690; 38665939). A mutation-agnostic alternative, AAV-Cx43, rescues multiple desmosomal ACM models (PMID: 41582809).

"Mutations in Plakophilin-2 (PKP2), encoding a desmosomal protein, account for approximately 40% of ARVC cases and result in reduced gene expression." — PMID: 38499690

"Late-stage AAV-PKP2 administration rescued desmosomal protein deficits and reduced pathological deficits including improved cardiac function in adult mice" — PMID: 39196150

"a single dose of AAV9:PKP2 gene delivery prevents disease development before the onset of cardiomyopathy and attenuates disease progression after overt cardiomyopathy" — PMID: 38499690

17. Single-cell/spatial transcriptomics reveal disease-associated cell states (F017)

• snRNA-seq of 5 ACM transplant hearts vs 4 donors showed increased fibroblast and adipocyte proportions and a disease-associated cardiomyocyte subpopulation (CM1) upregulating fibrosis-, metabolism-, and stress-related markers (PMID 40383406).
• scRNA-seq of 6 end-stage ARVC hearts + 2 controls identified NLRP3 as a therapeutic target; pharmacological NLRP3 inhibition prevented RV dilation/dysfunction in ARVC mice; RV was enriched for CCL3 (PMID 38185631).
• Spatial (Tomo-Seq) transmural profiling identified ZBTB11 specifically enriched at sites of active fibro-fatty replacement, inducing autophagy/cell-death programs (PMID 35576477).
• An integrated single-cell/single-nucleus atlas of 45 healthy, 70 DCM, 8 ARVC hearts identified ~1,100 myocardial B cells with disease-specific interaction networks (PMID 38736889).

"The snRNA-seq analysis revealed an increased proportion of fibroblasts and adipocytes in the left ventricles of LACM patients, suggesting a cellular basis for the fibrofatty remodeling observed in the disease." — PMID: 40383406

"Pharmacological inhibition of NLRP3 could prevent right ventricular dilation and dysfunction of mice with ARVC." — PMID: 38185631

"revealed Zinc finger and BTB domain-containing protein 11 (ZBTB11) to be specifically enriched at sites of active fibro-fatty replacement of myocardium" — PMID: 35576477

Ontology suggestions: CL:0000057 (fibroblast), CL:0000136 (adipocyte), CL:0000746 (cardiac muscle cell), CL:0000235 (macrophage), CL:0000236 (B cell).

18. Multi-omics implicates immune-metabolic dysregulation and nominates circulating biomarkers (F018)

Myocardial RNA-seq + label-free LC-MS/MS proteomics (n=10/group ACM vs DCM vs control) found 3,030 dysregulated mRNAs and 206 differentially expressed proteins in ACM vs control, enriched for immune activation, inflammation, ECM remodeling, and mitochondrial stress; three proteins (UCHL1, OCIAD1, desmoyokin) were consistently upregulated at transcript and protein level (PMID 41229088). Lipidomics of ACM fibro-fatty tissue showed increased saturated triglycerides and beige/brown fat markers; scRNA-seq showed pro-inflammatory macrophage accumulation, and plasma CCL3 predicted adverse heart-failure outcomes (PMID 40223064).

"Three novel proteins, UCHL1, OCIAD1 and desmoyokin, were consistently up-regulated at transcript and protein" — PMID: 41229088

"The expression of CCL3 in the fibro-fatty tissues was positively correlated with HF progression in patients with ACM." — PMID: 40223064

19. ARVC substantially impairs quality of life, with age-, sex-, and shock-dependent burden (F019)

A cross-sectional psychosocial survey of 159 ARVC patients (SF-36, Florida Shock Anxiety Scale, Florida Patient Acceptance Survey) found that ARVC patients reported lower physical and mental QoL than a U.S. normative sample. Patients aged 18–35 reported significantly lower mental QoL than older patients; ICD-shock history was associated with higher shock anxiety and lower mental QoL; and female patients reported significantly higher shock anxiety and lower mental QoL than males (PMID 28823501).

"ARVC patients reported lower physical and mental QOL compared to a normative U.S sample." — PMID: 28823501

"Female ARVC patients reported significantly higher shock anxiety and lower mental QOL compared to male patients." — PMID: 28823501

20. Male predominance is gene-specific, with DSP enriched in females (F020)

A SHaRe registry analysis of 3,410 genetically tested DCM/ACM patients found a 61% male predominance across genotype-positive, genotype-negative, and VUS subgroups (P=0.008), with significant gene-specific variation. TTN-truncating variants were less common in females (OR 0.42, 95% CI 0.33–0.54; P<0.01), whereas DSP variants (OR 3.3, 95% CI 2.35–4.78; P<0.01) and grouped non-TTN sarcomeric variants (OR 1.68, 95% CI 1.15–2.47; P<0.001) were more common in females (PMID 42159538).

"a 61% male predominance was present across subgroups of genotype positive, genotype negative, and variants of uncertain significance (P = 0.008), with significant gene-specific variation" — PMID: 42159538

"DSP (OR: 3.3 [95% CI: 2.35-4.78]; P < 0.01) and grouped non-TTN sarcomeric variants ... were more common (OR: 1.68 [95% CI: 1.15-2.47]; P < 0.001) in females" — PMID: 42159538

Section-by-Section Disease Profile

1. Disease Information

ARVC is an inherited cardiomyopathy characterized by fibrofatty replacement of the (predominantly right) ventricular myocardium, ventricular arrhythmias, and risk of sudden cardiac death, with later progression to heart failure. It is now understood as part of a broader arrhythmogenic cardiomyopathy (ACM) spectrum encompassing right-dominant (classic ARVC), left-dominant (ALVC), and biventricular forms.

• Key identifiers: MONDO:0016587; OMIM phenotype series (Naxos OMIM 601214, Carvajal OMIM 605676, ARVC-5/TMEM43); Orphanet ORPHA:247; ICD-10 I42.8; ICD-11 BC43.3; MeSH D019571 (Arrhythmogenic Right Ventricular Dysplasia).
• Synonyms: arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C); arrhythmogenic cardiomyopathy (ACM); arrhythmogenic ventricular cardiomyopathy (AVC).
• Information source: Aggregated disease-level resources (registries, OMIM, Orphanet, cohort studies), supplemented by individual clinical case reports and family-screening cohorts.

2. Etiology

Primary cause: Germline pathogenic variants in desmosomal genes (PKP2, DSP, DSG2, DSC2, JUP) and non-desmosomal genes (TMEM43, PLN, DES, FLNC, LMNA, TTN) (F001, F010). Environmental/lifestyle modifier: intense endurance exercise is the best-established disease accelerator, strongest for PKP2 (F003). Risk factors: male sex, family history, gene-elusive multifactorial background (F005, F008, F020). Protective factors: exercise restriction reduces phenotypic progression and arrhythmic risk (F003, F004); no well-established protective genetic variant is confirmed here. Gene–environment interaction: the "second-hit" model — a desmosomal/genetic predisposition combined with mechanical stress (exercise) or inflammation ("hot phase") triggers phenotypic expression (F003, F013).

3. Phenotypes

Age of onset: typically 2nd–4th decade; pediatric and recessive childhood-onset forms exist. Severity/progression: variable, progressive; episodic "hot phases" in DSP carriers (F013). QoL impact: significantly reduced physical and mental QoL, worse in young patients, women, and those with ICD shocks (F019).

4. Genetic/Molecular Information

Causal genes: PKP2 (~40%, most common), DSP, DSG2, DSC2, JUP (desmosomal); TMEM43, PLN, DES, FLNC, LMNA, TTN (non-desmosomal) (F001, F010). Variant types: missense, nonsense, frameshift, splice-site, and structural (e.g., PKP2 splice IVS10-1G>C; TMEM43 p.S358L founder missense; STRN deletion in dogs). Functional consequences: PKP2 haploinsufficiency (reduced expression); JUP loss-of-function; TMEM43 altering nuclear mechanics (F016, F010, F009). Modifier/gene-elusive: ~50% have no identified variant, implying modifier genes and multifactorial/polygenic contribution (F008). Epigenetic/chromosomal: not a principal driver; STRN deletion is the notable structural lesion (canine).

5. Environmental Information

The dominant non-genetic factor is intense/endurance physical exercise, which accelerates phenotype and arrhythmias (F003). Inflammatory/possibly infectious triggers may initiate "hot phases," clinically mimicking viral myocarditis, particularly in DSP carriers (F013). No specific occupational toxin or confirmed infectious agent is established as causal.

6. Mechanism / Pathophysiology — Causal Chain

1. Germline pathogenic variant in a desmosomal (PKP2/DSP/DSG2/DSC2/JUP)
   or non-desmosomal (TMEM43/PLN/DES/FLNC/LMNA) gene
│  leads to
▼
2. Structurally/functionally defective desmosome (or nuclear-membrane/
   cytoskeletal defect for TMEM43 → increased nuclear stiffness)
│  results in
▼
3. Impaired cardiomyocyte cell–cell adhesion at the intercalated disc;
   under mechanical stress (accelerated by endurance EXERCISE) →
├──► 4a. Cardiomyocyte detachment and DEATH
│         │ leads to
│         ▼
│    5a. Progressive myocyte loss → FIBRO-FATTY REPLACEMENT
│         (plakoglobin release → suppressed Wnt/β-catenin,
│          activated Hippo–YAP, PPARγ/TGF-β adipo-fibrogenic programs)
│
└──► 4b. Intercalated-disc remodeling:
  reduced Cx43 gap junctions + mislocalized/reduced NaV1.5
  │ results in
  ▼
     5b. Slowed conduction + reduced sodium current →
  ARRHYTHMIC SUBSTRATE (reentry) — often PRECEDES 5a
│
│  (branch) INFLAMMATION / autoimmunity / NLRP3 inflammasome
│  → "hot phases" (esp. DSP), amplifying injury
▼
6. Ventricular arrhythmias (VT/VF) → SUDDEN CARDIAC DEATH
   and, over time, RV → biventricular dysfunction → HEART FAILURE

Upstream events are the genetic lesion and adhesion failure; downstream are fibrofatty remodeling, electrical remodeling, arrhythmia, and heart failure. The electrical branch (5b) can dominate early (concealed phase), explaining SCD before overt structural disease (F002, F011, F012, F013).

Molecular pathways: Wnt/β-catenin (suppressed), Hippo–YAP (activated), TGF-β, PPARγ adipogenesis (F002). Cellular processes: apoptosis/cell death, inflammation, autophagy (ZBTB11), fibro-adipogenic differentiation (F002, F013, F017). Protein dysfunction: desmosomal loss-of-function/haploinsufficiency; Cx43/NaV1.5 mislocalization (F012, F016). Immune involvement: NLRP3 inflammasome, autoantibodies, macrophage/B-cell infiltration (F013, F017, F018). Omics: dysregulated immune-metabolic/mitochondrial pathways; biomarkers UCHL1, OCIAD1, desmoyokin, CCL3, ZBTB11 (F017, F018).

7. Anatomical Structures Affected

• Organ: heart, principally the right ventricle (UBERON:0002080), frequently the left ventricle (UBERON:0002084), especially DSP-ACM; body system cardiovascular (F014, F015).
• Tissue/cell: ventricular myocardium replaced by fibrous and adipose tissue; involved cells include cardiomyocytes (CL:0000746), fibroblasts (CL:0000057), adipocytes (CL:0000136), macrophages (CL:0000235), B cells (CL:0000236) (F002, F017).
• Subcellular: intercalated disc / desmosome / gap junction (GO:0005911, GO:0030057, GO:0005922); nuclear envelope for TMEM43 (GO:0005635) (F010, F012).
• Localization/lateralization: predominantly RV free wall / "triangle of dysplasia" and RVOT; often biventricular; DSP shows basal inferolateral LV involvement. Skin/hair in recessive syndromes (F007).

8. Temporal Development

Onset: typically 2nd–4th decade; concealed → electrical → structural → heart-failure phases. Progression: variable and generally progressive; episodic "hot phases" (F013). Course: lifelong chronic; arrhythmic risk lifelong; late heart failure. Critical periods: adolescence–young adulthood and periods of intense athletic training are windows of heightened vulnerability and intervention opportunity (F003, F005, F008).

9. Inheritance and Population

Prevalence ~1 in 2,000–5,000; predominantly autosomal-dominant with incomplete, age-dependent penetrance and variable expressivity; recessive cardiocutaneous forms (Naxos/JUP, Carvajal/DSP) (F005, F007, F008). Penetrance: TMEM43 p.S358L is fully penetrant; most desmosomal variants incompletely penetrant (F010, F008). Founder effects: TMEM43 p.S358L (Newfoundland/European origin) (F010). Sex ratio: overall male predominance (~61% in the DCM/ACM spectrum), but gene-specific — DSP enriched in females (F005, F020). Familial history in 30–50% (F008).

10. Diagnostics

• Clinical criteria: 2010 Revised Task Force Criteria (2020 Padua criteria add LV/tissue-characterization refinements) (F011).
• ECG/electrophysiology: T-wave inversion V1–V3, epsilon waves, late potentials, VT with LBBB morphology (F011).
• Imaging: echocardiography and cardiac MRI (RV dilation/dysfunction; late gadolinium enhancement, including isolated LV-LGE in DSP carriers) (F006, F014).
• Tissue: endomyocardial biopsy showing patchy, epicardial-predominant fibrofatty replacement.
• Biomarkers: troponin release in hot phases; investigational circulating miRNAs (miR-15a-5p/16-5p/92a-3p), plasma CCL3, proteomic candidates UCHL1/OCIAD1/desmoyokin (F006, F013, F018).
• Genetic testing: broad cardiomyopathy/arrhythmia gene panels, WES/WGS; single-gene/cascade testing of relatives; yield ~50% (F008).
• Differential diagnosis: idiopathic RVOT tachycardia, Brugada syndrome, athlete's heart, DCM, myocarditis, cardiac sarcoidosis, congenital RV aneurysms (F011).

11. Outcome/Prognosis

Principal outcomes are SCD (especially young/athletic males) and progressive biventricular heart failure. Combined RV+LV dysfunction is the strongest independent predictor of death/transplant (HR 6.3); tricuspid regurgitation and RV dysfunction are additional predictors (F015). The ARVC risk calculator estimates arrhythmic risk (F006). DSP-ACM carries particularly severe outcomes with LV fibrosis/dysfunction and HF (F014). QoL is substantially impaired (F019).

12. Treatment

No curative therapy. Pillars: exercise restriction; beta-blockers/antiarrhythmics (reduce arrhythmia, not SCD); catheter ablation (combined endo-epicardial preferred); ICD (only SCD-preventive intervention); heart transplantation for end-stage HF; bilateral cardiac sympathetic denervation for refractory VT (F004). Emerging disease-modifying: AAV9:PKP2 gene replacement and mutation-agnostic AAV-Cx43 (animal-validated, translating); apremilast and NLRP3 inhibition are experimental candidates (F016, F017). Personalized/genotype-guided management is increasingly relevant (DSP → immunomodulation in hot phases; PKP2 → exercise counseling and future gene therapy) (F013, F016).

NCIT suggestions: Implantable Cardioverter-Defibrillator; Catheter Ablation; Beta-Blocker Therapy; Amiodarone; Sotalol; Heart Transplantation; Gene Therapy.

13. Prevention

• Primary: exercise restriction / competitive-sport avoidance in gene carriers; preparticipation ECG screening (reduced athlete SCD in Italy) (F003, F004).
• Secondary: cascade family screening (clinical + genetic), regular surveillance of at-risk relatives — including gene-elusive families (F008).
• Tertiary: ICD, antiarrhythmics, ablation, HF therapy to prevent complications (F004, F015).
• Counseling: genetic counseling for family planning; risk stratification via the ARVC calculator (F006, F008).

14. Other Species / Natural Disease

Naturally occurring ARVC is well described in the Boxer dog (NCBITaxon:9615), associated with a striatin (STRN) deletion, causing SCD/HF with a middle-age onset; cats and other species also develop analogous disease (F009). This provides a spontaneous large-animal comparative model.

15. Model Organisms

• Mouse: Jup (plakoglobin) cardiomyocyte-restricted knockout recapitulates ventricular dilation, aneurysm, fibrosis, and spontaneous arrhythmias; Dsp-transgenic (R2834H) mice show exercise-accelerated RV disease with perturbed Wnt/β-catenin; Pkp2-deficient and PKP2 patient-splice-mutation mice model the commonest genotype and respond to AAV9:PKP2; TMEM43 models capture nuclear-stiffness mechanisms (F016, F002, F003, F010).
• iPSC-cardiomyocytes: patient-derived (e.g., DSP p.Glu952Ter) hiPSC-CMs show loss of cohesion rescued by apremilast — an in vitro human model.
• Applications: dissecting adhesion/signaling, arrhythmogenesis, and testing gene/pharmacologic therapies. Limitations: murine electrophysiology and RV geometry differ from human; incomplete recapitulation of the human "hot phase"/immune component.

Mechanistic Model / Interpretation

The evidence converges on a unifying model in which a genetic adhesion defect at the intercalated disc, unmasked by mechanical or inflammatory stress, drives two partially independent downstream arms: (1) an electrical arm (Cx43/NaV1.5 remodeling → conduction slowing → reentry), which can produce arrhythmia and SCD before overt structural change; and (2) a structural arm (myocyte death → plakoglobin/Hippo/Wnt/PPARγ/TGF-β-driven fibrofatty replacement), which produces the imaging hallmark and, ultimately, biventricular heart failure. Inflammation/autoimmunity (NLRP3, autoantibodies, CCL3, macrophage/B-cell infiltration) modulates both arms and dominates "hot phases," especially in DSP genotype. Genotype shapes the clinical face of the disease: PKP2 → classic right-dominant, exercise-sensitive; TMEM43 → most aggressive, fully penetrant; DSP → left-dominant/biventricular, inflammatory, female-enriched.

Evidence Base (selected)

Limitations and Knowledge Gaps

1. Gene-elusive disease (~50%): the genetic architecture of half of probands remains undefined, limiting variant-directed prevention and therapy (F008).
2. Penetrance/expressivity unexplained: the "genotype-phenotype plasticity" — why family members with identical variants diverge widely — lacks a validated modifier/polygenic explanation (F008).
3. Prognostic tools: the ARVC risk calculator was developed largely in 2010-Task-Force-Criteria populations and may under-serve DSP/ALVC phenotypes not meeting RV-focused criteria (F006, F014).
4. Biomarkers investigational: CCL3, miRNAs, UCHL1/OCIAD1/desmoyokin require prospective validation before clinical use (F006, F018).
5. Therapy evidence: no randomized trials of exercise restriction, drug therapy, or screening; gene therapies are pre-clinical/early-phase and untested for long-term human safety/durability (F004, F016).
6. Model limitations: murine and iPSC systems incompletely recapitulate human RV geometry, chronic remodeling, and the immune/hot-phase component.

Proposed Follow-up Experiments / Actions

1. Genetics of gene-elusive ARVC: apply large-scale WGS + polygenic risk scoring and rare-variant burden testing in gene-elusive probands and families to define missing heritability (addresses F008).
2. Prospective biomarker validation: multi-site cohorts to validate plasma CCL3, miR-15a-5p/16-5p/92a-3p, and UCHL1/OCIAD1/desmoyokin against arrhythmic and HF endpoints; integrate into the risk calculator (F006, F018).
3. DSP-specific risk model: develop and validate an ALVC/DSP-oriented risk score incorporating LV-LGE and inflammatory markers, since these patients evade RV-centric criteria (F014).
4. Clinical translation of gene therapy: advance AAV9:PKP2 and mutation-agnostic AAV-Cx43 to first-in-human trials with predefined safety, durability, and functional endpoints (F016).
5. Anti-inflammatory/NLRP3 trials: test NLRP3 inhibition and immunomodulation (guided by DSP genotype and hot-phase status) in randomized settings (F013, F017).
6. Exercise-prescription RCTs: quantify the dose–response of exercise restriction on phenotype progression, genotype-stratified (especially PKP2) (F003).
7. Single-cell longitudinal atlases: map the transition from concealed → electrical → structural phases at single-cell/spatial resolution to identify early, reversible intervention points (F017).

Answer to the Research Question

Arrhythmogenic right ventricular cardiomyopathy (ARVC/MONDO:0016587) is an inherited, mostly autosomal-dominant cardiomyopathy with incomplete penetrance in which pathogenic variants in desmosomal genes (PKP2 ~40%, DSP, DSG2, DSC2, JUP) and non-desmosomal genes (TMEM43, PLN, DES, FLNC, LMNA)—identified in ~50% of patients—impair cardiomyocyte adhesion at the intercalated disc, so that mechanical stress (accelerated by endurance exercise) and inflammation drive myocyte death, plakoglobin/Hippo–YAP-mediated Wnt suppression and PPARγ/TGF-β-driven fibrofatty replacement (right-ventricular, frequently biventricular/left-dominant), and Cx43/NaV1.5 remodeling, producing life-threatening ventricular arrhythmias, sudden cardiac death, and later heart failure. Diagnosis uses the 2010 Revised Task Force/2020 Padua criteria (ECG, CMR-LGE, genetics); risk is stratified with the validated ARVC risk calculator (arrhythmia) and biventricular dysfunction (death/transplant, HR 6.3); and management—exercise restriction, beta-blockers/antiarrhythmics, catheter ablation, and the only SCD-preventive intervention, the ICD—is complemented by disease-modifying gene therapies (AAV9:PKP2; mutation-agnostic AAV-Cx43) validated in animal models. The disease occurs naturally in Boxer dogs (STRN deletion) and is modeled in Jup/Dsp/Pkp2/Tmem43 mice and patient iPSC-cardiomyocytes.

Artifacts

• OpenScientist final report
• OpenScientist final report

Reference Validation

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All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• HP:0001645 (2 mentions) - the report calls it "Sudden cardiac death", "Outcome"; HP calls it Sudden cardiac death
• HP:0007502 (2 mentions) - the report calls it "Woolly hair"; HP calls it Follicular hyperkeratosis
• HP:0001962 (1 mention) - the report calls it "Symptom"; HP calls it Palpitations
• HP:0001279 (1 mention) - the report calls it "Symptom"; HP calls it Syncope
• HP:0001714 (1 mention) - the report calls it "Physical/imaging"; HP calls it Ventricular hypertrophy
• HP:0001644 (1 mention) - the report calls it "Physical/imaging"; HP calls it Dilated cardiomyopathy
• HP:0001635 (1 mention) - the report calls it "Clinical sign"; HP calls it Congestive heart failure
• HP:0012231 (1 mention) - the report calls it "Lab/ECG"; HP calls it Serous retinal detachment

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

• GO:0007156 (1 mention) - the report calls it "homophilic cell adhesion via plasma-membrane adhesion molecules"; GO calls it homophilic cell-cell adhesion
• GO:0005911 (2 mentions) - the report calls it "cell–cell junction / intercalated disc"; GO calls it cell-cell junction
• NCBITaxon:9615 (2 mentions) - the report calls it "Canis lupus familiaris", "Boxer dog"; NCBITaxon calls it Canis lupus familiaris, and lists "dog" among its other names
• HP:0004756 (2 mentions) - the report calls it "Ventricular arrhythmia"; HP calls it Ventricular tachycardia
• UBERON:0002080 (1 mention) - the report calls it "right ventricle", "Organ: heart, principally the right ventricle"; UBERON calls it heart right ventricle

Terms named inconsistently

The report gives these identifiers more than one name of its own:

• HP:0001645 - called "Sudden cardiac death", "Outcome"
• NCBITaxon:9615 - called "Canis lupus familiaris", "Boxer dog"
• UBERON:0002080 - called "right ventricle", "Organ: heart, principally the right ventricle"

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: ORPHA.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) — Comprehensive Disease Characteristics Report

Target disease: Arrhythmogenic right ventricular cardiomyopathy MONDO ID: MONDO:0016587 · Category: Mendelian (autosomal dominant, desmosomal) Investigation: 5 iterations · 20 confirmed findings · 81 papers reviewed

Summary

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease defined by progressive fibrofatty replacement of the ventricular myocardium — classically the right ventricle — that creates an electrically unstable substrate producing ventricular arrhythmias, heart failure, and sudden cardiac death (SCD), especially in young people and endurance athletes. It is fundamentally a disease of the cardiac desmosome: pathogenic loss-of-function variants in desmosomal genes account for the majority of cases, with PKP2 (plakophilin-2) the single most common cause, followed by DSP, DSG2, DSC2, and JUP, plus important non-desmosomal causes including TMEM43, PLN, and FLNC. Desmosomal gene variants account for 67.4% of ARVC cases in cohort studies and 96.1% of pathogenic variants in ClinVar (PMID: 42366226).

Mechanistically, destabilization of the intercalated disc triggers a convergent signaling cascade: activation of the Hippo pathway (Merlin/NF2 → MST1/2 → LATS1/2 → YAP phosphorylation), suppression of canonical Wnt/β-catenin signaling via nuclear plakoglobin/YAP–β-catenin sequestration, and engagement of TGF-β signaling — together driving a pro-adipogenic, pro-fibrotic transcriptional program. A shared, mutation-agnostic downstream feature is downregulation of the gap-junction protein connexin-43 (Cx43), which contributes to arrhythmogenesis independent of the causal gene. Increasingly, ARVC is also recognized as an inflammatory cardiomyopathy with episodic "hot phases" that mimic myocarditis. The key environmental modifier is endurance/high-intensity exercise, which accelerates penetrance and arrhythmic risk in a dose-dependent manner and largely explains the observed male predominance.

Clinically, ARVC has a prevalence of ~1:2,000 to 1:5,000, presents typically between the second and fourth decades of life, and is diagnosed by the multiparametric 2010 modified Task Force Criteria and 2020 Padua criteria integrating imaging, ECG, tissue, arrhythmia, and genetic data. Management is currently palliative: exercise restriction, beta-blockers and antiarrhythmics, catheter ablation, and ICD implantation guided by the 2019 ARVC risk calculator, with heart transplantation reserved for end-stage disease. A new generation of AAV-based gene therapies — PKP2 gene replacement (LX2020) and mutation-agnostic Cx43 restoration — show strong preclinical efficacy and represent the first potentially disease-modifying treatments.

1. Disease Information

ARVC is an inherited cardiomyopathy characterized by progressive fibrofatty replacement of ventricular myocardium, ventricular arrhythmias, and increased sudden cardiac death risk. It was originally called arrhythmogenic right ventricular dysplasia (ARVD), later broadened to arrhythmogenic cardiomyopathy (ACM) to encompass left-dominant and biventricular forms; the 2023 ESC guidelines reintroduced "ARVC" specifically for fibrofatty right ventricular disease while using "non-dilated left ventricular cardiomyopathy" for left-sided phenotypes (PMID: 39980788).

Key identifiers: - MONDO: MONDO:0016587 - OMIM: ARVD1 (107970, TGFB3), ARVD2 (600996, RYR2), ARVD5 (604400, TMEM43), ARVD8 (607450, DSP), ARVD9 (609040, PKP2), ARVD10 (610193, DSG2), ARVD11 (610476, DSC2), ARVD12 (611528, JUP) - Orphanet: ORPHA:247 - ICD-10: I42.8 · ICD-11: BC43.3 · MeSH: D019571 (Arrhythmogenic Right Ventricular Dysplasia)

Synonyms/alternative names: arrhythmogenic right ventricular dysplasia (ARVD), arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), arrhythmogenic cardiomyopathy (ACM), right ventricular cardiomyopathy. Left-predominant forms are termed arrhythmogenic left ventricular cardiomyopathy (ALVC).

Information source: Data are derived from aggregated disease-level resources (OMIM, Orphanet, ClinVar), disease registries (Johns Hopkins ARVC Registry, Utrecht, SHaRe, Scandinavian cohorts), and clinical/pathology studies rather than individual EHR-level extraction.

2. Etiology

Disease Causal Factors

The primary cause of ARVC is genetic, predominantly heterozygous loss-of-function variants in genes encoding the cardiac desmosome — the cell–cell adhesion junction of the intercalated disc. Desmosomal gene variants are predominant, "accounting for 67.4% of cases in cohort studies and 96.1% of pathogenic variants in ClinVar" (PMID: 42366226). Non-desmosomal genetic causes include TMEM43, PLN, FLNC, LMNA, SCN5A, DES, and RBM20 (PMID: 34970070).

Genetic Risk Factors

• Causal genes: PKP2 (most common), DSP, DSG2, DSC2, JUP, TMEM43, PLN, FLNC.
• Founder/high-penetrance variants: TMEM43 p.S358L (fully penetrant, Newfoundland founder); PKP2 Q59L (Finnish founder, ~20% penetrance).
• Modifier effect of multiple variants: carriers of >1 mutation (~4%) have earlier VT/VF (28±12 yr) and worse outcomes (PMID: 25616645).

Environmental Risk Factors

• Endurance/high-intensity exercise is the dominant modifier: "intense exercise may accelerate the phenotypic expression and the propensity to ventricular arrhythmias in patients with ACM" (PMID: 40470644).
• Male sex and age are associated with worse arrhythmic outcomes, but much of the sex effect is mediated by higher exercise dose in men (PMID: 33829244).
• Family history of ARVC/SCD.

Protective Factors

• Exercise restriction reduces arrhythmic risk and slows phenotypic progression — the primary modifiable protective intervention.
• No well-established protective genetic variants have been defined for ARVC. Non-carrier status among relatives in cascade screening is effectively protective.

Gene–Environment Interactions

The exercise–genotype interaction is the paradigmatic GxE relationship in ARVC. Mechanical load from endurance exercise stresses an already compromised desmosome, accelerating fibrofatty remodeling and arrhythmia. In a longitudinal cohort, male sex marked arrhythmia risk (OR 2.6) but lost significance after adjusting for exercise dose, indicating exercise mediates much of the sex difference (PMID: 33829244).

3. Phenotypes

ARVC symptoms typically emerge from the second to fourth decade of life (PMID: 25894016). The disease is progressive and often episodic (with arrhythmic and inflammatory "hot phase" flares).

In a tertiary cohort, "patients in the definite group were more symptomatic, with palpitations (57% vs. 17%), syncope (35% vs. 6%) and shortness of breath (28% vs. 5%, p < 0.001). T-wave inversion in V1-V3 and epsilon waves were observed only in the definite group" (PMID: 36635648).

Severity/progression: Variable and progressive; ranges from a "concealed phase" (arrhythmic risk without overt structure) to end-stage biventricular failure. In a Brazilian cohort, 5-year cumulative life-threatening arrhythmic event (LTAE) probability was 30% and HF-death/heart transplant 10% (PMID: 36720007).

Quality of life: Impaired by arrhythmia burden, ICD shocks, exercise restriction (particularly affecting athletes), heart-failure symptoms, and the psychological burden of SCD risk and cascade family screening. Formal EQ-5D/SF-36 disease-specific data were not identified in this investigation.

4. Genetic / Molecular Information

Causal Genes and Genotype–Phenotype Correlations

Variant Classification and Type

Variants are classified per ACMG/AMP guidelines (pathogenic, likely pathogenic, VUS). Most are truncating/loss-of-function (frameshift, nonsense, splice-site) — e.g., the PKP2 spectrum reported "5 frameshift, 2 nonsense, 2 splicing, 1 missense variants" (PMID: 34191271) — with important missense exceptions such as TMEM43 p.S358L. NGS panels in inherited heart disease clinics carry high VUS rates (~54%) (PMID: 39009076). Pathogenicity hotspots localize to critical domains (PKP2 ARM7/ARM8; DSG2 N-terminal cadherin repeats), whereas incidentally identified variants distribute like background population variation (PMID: 30985088).

Allele Frequency and Penetrance

ARVC-associated desmosomal variants are surprisingly prevalent in the general population but with reduced penetrance. In a Finnish cohort (n=6,334), "the collective prevalence of all 5 mutations... was 31 of 6,334 individuals, or 0.5%. The apparent founder mutation PKP2 Q59L is present in 0.3% of Finns and was previously shown to have an approximately 20% disease penetrance" (PMID: 21397041) — roughly 1 in 200 Finns carries a desmosomal variant.

Origin and Functional Consequences

Variants are germline. Functional consequence is predominantly loss of function / haploinsufficiency of desmosomal adhesion, with some dominant-negative effects. Endomyocardial samples of a DSG2 deletion carrier showed reduced immunoreactive signal for desmoglein-2, plakophilin-2, plakoglobin, and desmoplakin — indicating collective destabilization of the desmosomal complex (PMID: 21397041).

Modifier Genes, Epigenetics, Chromosomal

Carriage of a second variant modifies severity (PMID: 25616645). Epigenetic regulation involves tissue microRNAs: "miR-21-5p and miR-29b-3p are associated with fibrosis and extracellular matrix remodeling, whereas miR-133a-b and miR-130a are linked to cardiomyocyte integrity loss and desmosomal dysfunction" (PMID: 42353884); miR-217-5p, miR-708-5p, miR-135b link to Wnt/β-catenin and Hippo. No recurrent large-scale chromosomal abnormalities cause ARVC, though structural deletions (e.g., DSG2) occur.

5. Environmental Information

• Environmental factors: No environmental toxin or radiation exposure causes ARVC. The dominant non-genetic factor is mechanical/hemodynamic load from exercise.
• Lifestyle factors: Endurance and high-intensity/competitive sport is the principal lifestyle modifier — accelerating penetrance and arrhythmia; ARVC is among the most common causes of SCD in athletes (PMID: 40470644; PMID: 42305082).
• Infectious agents: None cause ARVC. However, desmosomal cardiomyopathy can present as myocarditis-like "hot phases" (most commonly DSP) with troponin release mimicking acute myocarditis, involving NLRP3-inflammasome activation and anti-desmosomal/anti-intercalated-disc autoantibodies (PMID: 41448261). This aseptic intracellular inflammation is frequently misdiagnosed as viral myocarditis, particularly in children (PMID: 41255689).

6. Mechanism / Pathophysiology

Core Causal Chain

Desmosomal LOF variant (PKP2/DSP/DSG2/DSC2/JUP)
│
▼
Intercalated disc destabilization  →  ↓ Connexin-43 (Cx43) gap junctions
│                                       │
▼                                       ▼
Plakoglobin translocates to nucleus     Slowed conduction, Na-current↓
│                                (arrhythmogenic substrate)
▼
Hippo activation (Merlin/NF2→MST1/2→LATS1/2→YAP-P)
│
▼
YAP-P + phospho-β-catenin sequestered  →  ↓ canonical Wnt/β-catenin, ↓TEAD
│
▼
Pro-adipogenic + pro-fibrotic transcription  (+ DSC2→TCF7→TGF-β2 in fibroblasts)
│
▼
FIBROFATTY REPLACEMENT of myocardium  →  VT/VF, SCD, heart failure
│
   (accelerated by exercise; amplified by inflammation/autoantibodies)

Molecular Pathways

Multiple independent reviews converge on canonical and non-canonical WNT signaling, the Hippo-YAP pathway, and TGF-β signaling as the central dysregulated pathways: "these pathways include canonical and non-canonical WNT signalling, the Hippo-Yes-associated protein (YAP) pathway and transforming growth factor-β signalling" (PMID: 31028357). "Imbalance in the Wnt/β-catenin signaling and also in the crosslinked Hippo pathway leads to the transcription of proadipogenic and profibrotic genes" (PMID: 36289882). Experimentally, "altered protein constituents of intercalated discs were associated with activation of the upstream Hippo molecules" (PMID: 24276085). A distinct fibrosis arm operates through DSC2: "DSC2 deficiency upregulated transcription factor 7 (TCF7) expression, promoting its binding to TGF-β2 promoter regions to enhance TGF-β2 transcription in cardiac fibroblasts" (PMID: 42366226).

Shared Mutation-Agnostic Defect: Cx43

"The reduction in expression of the ventricular gap junction protein Cx43 (connexin-43) is a common molecular alteration underlying desmosomal junctional deficits and arrhythmias" (PMID: 41582809) — making Cx43 both a unifying mechanism and a therapeutic target.

Cellular Processes

• Cardiomyocyte death (apoptosis/necrosis) → replacement fibrosis.
• Fibro-adipogenic differentiation of cardiac progenitor/interstitial cells.
• Microtubule detyrosination: PKP2 loss increases microtubule detyrosination and membrane stiffness, reducing sodium current; parthenolide rescues both (PMID: 42366968).
• Inflammation: ACM is increasingly framed as an inflammatory cardiomyopathy — desmosomal variants activate NFκB and GSK3β signaling, promoting cytokine release and immune infiltration that may precede structural change (PMID: 42193878).

Immune / Autoantibody Involvement

"Three pathogenic ACM-IgGs activated GSK-3β upstream of p38MAPK, leading to phosphorylation and junctional loss of β-catenin. GSK-3β inhibition rescued the loss of cell cohesion" (PMID: 42219531) — establishing a pathogenic autoantibody/GSK-3β axis and a druggable node.

Single-cell / Molecular Profiling

Single-nucleus RNA-seq of left-dominant ACM hearts (5 ACM vs 4 donors) "revealed an increased proportion of fibroblasts and adipocytes in the left ventricles of LACM patients, suggesting a cellular basis for the fibrofatty remodeling observed in the disease," plus a disease-associated cardiomyocyte subpopulation (CM1) upregulating fibrosis/metabolism/stress markers (PMID: 40383406).

Suggested ontology terms: GO:0016055 (Wnt signaling), GO:0035329 (Hippo signaling), GO:0007179 (TGF-β receptor signaling), GO:0007507 (heart development), GO:0050900 (leukocyte migration); CL:0000746 (cardiac muscle cell), CL:0000057 (fibroblast), CL:0000136 (adipocyte).

7. Anatomical Structures Affected

Organ level: The heart (UBERON:0000948), primarily the right ventricle (UBERON:0002080); secondary/left ventricle (UBERON:0002084) in biventricular and left-dominant variants. Body system: cardiovascular (UBERON:0004535).

"Triangle of dysplasia": Structural remodeling primarily involves three RV regions — "the three regions ('ARVC triangle') primarily involved in ARVC structural remodeling": RV inflow/subtricuspid region, RV outflow tract, and RV apex (PMID: 33927217). Ex vivo 9.4T MRI showed high fat content in these regions: "the healthy heart exhibited twice less fat than the ARVC heart (31.9%, 28.7% and 1.3% of fat in the same regions, respectively)," histologically confirmed, with fibrosis also present in fat-poor areas (PMID: 33927217).

Tissue/cell level: Cardiac muscle tissue is replaced by fibrous (connective) and adipose tissue. Cell populations: cardiomyocytes (CL:0000746, lost), fibroblasts (CL:0000057, expanded), adipocytes (CL:0000136, expanded) (PMID: 40383406).

Subcellular level: The intercalated disc / desmosome (GO:0030057 desmosome; GO:0005912 adherens junction), gap junction (GO:0005921), nucleus (plakoglobin/YAP translocation; increased nuclear stiffness in TMEM43 carriers), and cytoskeleton/microtubules (GO:0005874).

Progression pattern: Fibrofatty replacement typically advances from epicardium/mid-myocardium toward endocardium. Left-dominant/biventricular variants involve LV lateral/posterior basal segments — "cardiac magnetic resonance showed LV late gadolinium enhancement in the LV lateral and posterior basal segments in all patients" (PMID: 33197325).

Lateralization: RV-dominant (classic), LV-dominant (ALVC), or biventricular.

8. Temporal Development

• Onset: Usually adolescence to adulthood (2nd–4th decades) (PMID: 25894016); pediatric-onset ARVD occurs (mean 12±4 yr) and may be misdiagnosed as myocarditis (PMID: 31375646). Late presentation (≥50 yr) occurs in ~21% and is not benign — 65% sustained VA over 6 years (PMID: 28215569).
• Onset pattern: Insidious/chronic, punctuated by acute arrhythmic or inflammatory ("hot phase") episodes.
• Disease stages: (1) Concealed phase — arrhythmic risk with subtle/absent structure; (2) Overt electrical disease — symptomatic arrhythmias, ECG changes, structural RV abnormality; (3) RV failure; (4) Biventricular/end-stage failure.
• Progression rate: Variable, generally slowly progressive over decades; accelerated by exercise.
• Course pattern: Progressive with episodic arrhythmic/inflammatory flares.
• Duration: Chronic, lifelong.
• Critical periods: Adolescence/young adulthood coincident with sport participation is the critical window for SCD and for intervention (exercise restriction, ICD).

9. Inheritance and Population

• Prevalence: ~1:2,000 to 1:5,000: "Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic heart disease with a prevalence of 1 : 2000 to 1 : 5000" (PMID: 40202346).
• Inheritance: Predominantly autosomal dominant with reduced, age-dependent penetrance and variable expressivity. Recessive cardiocutaneous forms: Naxos disease — "mutations in the genes encoding the desmosomal proteins plakoglobin and desmoplakin have been identified as the cause of Naxos disease" (JUP; woolly hair + palmoplantar keratoderma; ~100% cardiac penetrance by adolescence — PMID: 16722579) — and Carvajal syndrome (DSP, left-dominant — PMID: 25824144).
• Penetrance: Incomplete and age-dependent — e.g., PKP2 Q59L ~20% penetrance (PMID: 21397041); by contrast TMEM43 p.S358L is fully penetrant (PMID: 24598986).
• Founder effects: TMEM43 p.S358L (Newfoundland; "an estimated age of 1300-1500 years for the mutation, which proves the European origin of the Newfoundland mutation" — PMID: 24598986); PKP2 Q59L (Finland).
• Carrier frequency: ~0.5% collective desmosomal-variant carrier prevalence (~1 in 200) in Finland (PMID: 21397041).
• Sex ratio: Male predominance. "Ventricular arrhythmia had occurred at inclusion or occurred during follow-up in 85 patients (33% of females vs. 55% of males, P = 0.002). Exercise doses were higher in males compared with females," and the sex effect lost significance after adjustment for exercise dose (PMID: 33829244); SHaRe registry showed 61% male predominance with gene-specific variation (DSP more common in females, OR 3.3) (PMID: 42159538).
• Age distribution: Clinically overt from 2nd–4th decades; a substantial minority present after 50.

10. Diagnostics

Clinical Criteria

Diagnosis uses the multiparametric 1994 Task Force Criteria, revised as the 2010 modified Task Force Criteria with quantitative structural thresholds, and updated by the 2020 Padua criteria (adding left-predominant/biventricular criteria incorporating CMR late gadolinium enhancement). "The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria" (PMID: 38512728); "in 2010, the task force criteria were revised to include quantitative abnormalities" (PMID: 32032135). The 2010 criteria are more specific: "Of 968 patients, 220 (22.7%) fulfilled either a major or a minor 1994 TFC, and 25 (2.6%) fulfilled any of the 2010 TFC criterion" (PMID: 24996808).

Tests

• ECG: T-wave inversion V1–V3, epsilon wave, QRS fragmentation, low precordial QRS voltage, signal-averaged ECG late potentials, LBBB-morphology VT.
• Imaging: Echocardiography and cardiac MRI (gold standard) demonstrating RV dilatation, reduced RVEF, aneurysms/regional wall-motion abnormalities, and late gadolinium enhancement; RV angiography ("pile d'assiettes" appearance) in select cases.
• Tissue: Endomyocardial biopsy showing fibrofatty replacement and reduced desmosomal immunoreactivity.
• Genetic testing: Broad cardiomyopathy/arrhythmia NGS gene panels (not limited to validated ARVC genes) are recommended; WES/WGS in select cases. Panels have ~31% diagnostic yield with ~54% VUS in ICC clinics (PMID: 39009076). "Using a broad cardiomyopathy and arrhythmia gene panel in ARVC probands, rather than limiting testing to validated ARVC genes alone, is warranted" (PMID: 42389803).
• Biomarkers: Circulating miR-15a-5p, miR-16-5p, miR-92a-3p differentiate high- vs low-risk patients (PMID: 40222719).
• Emerging: Machine-learning models (gradient-boosted trees, AUC 0.943) enhance ARVC detection from multimodal data (PMID: 41884351).

Differential Diagnosis

Idiopathic RVOT VT, myocarditis (including hot-phase overlap), cardiac sarcoidosis, Brugada syndrome, dilated cardiomyopathy, athlete's heart, and non-desmosomal phenocopies (e.g., RIT1-related) (PMID: 41918562).

Screening

First-degree relatives undergo cascade genetic + clinical screening (ECG, echo, Holter, CMR) with genetic counseling.

11. Outcome / Prognosis

• Mortality/SCD: Principal risk is SCD from ventricular arrhythmia, especially in young athletes — "ACM was the cause of SCD in 29% of athletes" in a 4-decade national juvenile registry (PMID: 42305082).
• Natural history: "The 5-year cumulative probability of LTAE was 30% and HF-death/HTx was 10%" (PMID: 36720007).
• Genotype-specific prognosis: PKP2 better prognosis (PMID: 34191271); DSG2/DSP higher HF/transplant risk; TMEM43 p.S358L malignant — "TMEM patients had worse composite endpoint of death or transplantation (60% vs. 0, P = 0.035; log-rank P = 0.013)" (PMID: 28960618).

Risk Stratification

The 2019 ARVC risk calculator estimates 5-year sustained-VA risk. Enhancers:

Other established prognostic factors: prior cardiac arrest/syncope, sustained VT, RV/LV dysfunction, extent of T-wave inversion, male sex, and young age.

12. Treatment

Current therapy is palliative — it manages arrhythmias and heart failure but does not address the molecular substrate (PMID: 41301430).

Pharmacotherapy (MAXO:0000058 pharmacotherapy)

• Beta-blockers — grade I for extrasystoles/VT: "Beta-blockers are recommended for patients with extrasystoles or ventricular tachycardia (grade I recommendation). If beta-blockers alone have an insufficient effect, amiodarone, flecainide or sotalol can be added (grade IIa)" (PMID: 40202346). Drug classes: beta-adrenergic antagonists, amiodarone (CHEBI:2663), sotalol, flecainide.
• Heart failure therapy for ventricular dysfunction.

Interventional / Device

• Catheter ablation — grade IIa for recurrent VT; palliative. Meta-analysis (24 studies, 717 patients): "acute efficacy of 89.8%, major complication of 5.2%, follow-up of 28.9 months, VT freedom of 75.3%, all-cause mortality of 1.1% and heart transplantation of 0.6%"; "epicardial ablation is associated with better long-term VT freedom" (OR 0.50 vs endocardial-only) (PMID: 33343648). DSP-ACM and TMEM43 require endo-epicardial mapping (PMID: 38206263).
• ICD (MAXO implantable cardioverter defibrillator) — grade I for SCD survivors; primary-prevention decisions guided by the ARVC risk calculator; earlier ICD reasonable for PLN/FLNC/LMNA genotypes.
• Heart transplantation (MAXO:0000384) — for end-stage HF or intractable arrhythmias.

Lifestyle

• Exercise restriction — central, because intense exercise accelerates phenotype and arrhythmia (PMID: 40470644).

Emerging / Experimental Therapies

• AAV PKP2 gene replacement (LX2020, AAVrh10): "we show minimal doses required for efficacy for AAVrh10.PKP2 (LX2020) to rescue cardiac (molecular and especially RV) deficits, arrhythmia burden and survival in PKP2 ACM mice," with no adverse events in non-human-primate safety studies (PMID: 40175378).
• Mutation-agnostic AAV-Cx43 restoration: "Administration of AAV-Cx43 (adeno-associated-viral-mediated connexin-43) gene therapy alleviated the severe biventricular dilatation, contractile dysfunction, and arrhythmias, while prolonging lifespan in 2 severe desmosomal ACM mouse models" (PMID: 41582809).
• AAV8-FGF21: mitigated structural change and adrenergic arrhythmias in PKP2-cKO mice (PMID: 41759869).
• Small molecules: parthenolide (microtubule detyrosination — PMID: 42366968); GSK-3β inhibition (autoantibody axis — PMID: 42219531); apremilast (PDE4 inhibitor; improves cardiomyocyte cohesion via plakoglobin Ser665 phosphorylation and ERK1/2 — PMID: 41185038).
• Immunomodulation during active inflammatory phases (NFκB/GSK3β/cytokine-directed) (PMID: 42193878).

Pharmacogenomics / Personalized Medicine

Genotype-guided management is emerging (e.g., earlier ICD for PLN/FLNC/LMNA; gene-specific ablation strategy) (PMID: 34970070).

13. Prevention

• Primary prevention: Exercise restriction/avoidance of competitive endurance sport in carriers; ICD in high-risk individuals.
• Secondary prevention: Cascade genetic and clinical screening of first-degree relatives with pre-/post-test genetic counseling; genotype-positive/phenotype-negative relatives receive periodic follow-up. "Pre-test and post-test counseling were provided to probands and cascade screening offered to relatives" (PMID: 39009076). Family screening is warranted even in gene-elusive ARVC — 17% of gene-elusive families harbored a P/LP variant in a different cardiomyopathy/arrhythmia gene (PMID: 42389803).
• Tertiary prevention: ICD, ablation, and HF therapy to prevent SCD and progression.
• Risk stratification: ARVC risk calculator + CMR LGE/strain + electroanatomic mapping (Section 11).
• Immunization/public health: Not applicable (non-infectious, non-communicable Mendelian disease).
• Counseling: Genetic counseling for family planning; preimplantation/prenatal testing possible for known familial variants.

14. Other Species / Natural Disease

• Taxonomy: Homo sapiens (NCBI:txid9606); naturally occurring in Canis lupus familiaris (dog, NCBI:txid9615).
• Breeds: Boxer and English bulldog dogs. "This myocardial disorder has also been described in Boxer and English bulldogs (EBs)" (PMID: 40540101). Boxer ARVC is associated with a striatin (STRN) deletion.
• Comparative pathology: Canine ACM recapitulates human ECG phenotype — in 59 EBs, ACM dogs showed wider QRS and longer terminal activation, and "the TWI and ɛ wave in ACM group were respectively present in 19% and 32%," correlating with echocardiographic RV parameters (PMID: 40540101).
• Orthologous genes: PKP2, DSP, DSG2, DSC2, JUP, TMEM43 are conserved across mammals; STRN in dogs.
• Zoonotic potential: None (genetic disease, not transmissible).

15. Model Organisms

Comprehensive reviews of intercalated-disc-gene animal models confirm that murine and hiPSC models have driven mechanistic understanding and therapeutic development (PMID: 38892395; PMID: 42137277). Limitations: murine models incompletely capture the exercise-dependent, slowly progressive, and inflammatory "hot-phase" aspects of human disease and human variant heterogeneity. Resources: MGI, IMPC, Cellosaurus, Alliance of Genome Resources, OMIA.

Mechanistic Model / Interpretation

ARVC is best understood as a desmosome-initiated, signaling-amplified, mechanically-triggered fibrofatty cardiomyopathy. The upstream event is loss of desmosomal adhesion at the intercalated disc. This has two immediate consequences that map onto the two clinical hallmarks:

1. Electrical instability (upstream, early): reduced Cx43 gap junctions and altered sodium-channel function (partly via microtubule detyrosination) slow conduction and create a re-entrant substrate — explaining why arrhythmias and SCD can precede overt structural disease (the concealed phase). This is the mutation-agnostic arrhythmia axis and the rationale for Cx43-restoration therapy.

2. Structural remodeling (downstream, progressive): nuclear translocation of plakoglobin, Hippo-YAP activation, Wnt/β-catenin suppression, and TGF-β/TCF7 engagement redirect transcription toward adipogenesis and fibrosis, producing the "triangle of dysplasia" fibrofatty replacement, RV dilatation/aneurysms, and eventually biventricular failure.

Layered on top is an inflammatory amplifier (NFκB/GSK3β, NLRP3-inflammasome, anti-DSG2 autoantibodies) that produces episodic myocarditis-like hot phases, and a mechanical accelerator (endurance exercise) that increases wall stress on an adhesion-deficient myocardium — accounting for the dose-dependent exercise effect and the male predominance mediated by exercise. Genotype tunes the phenotype: PKP2 is RV-predominant and comparatively benign; DSG2/DSP skew toward LV involvement and heart failure; TMEM43 p.S358L is fully penetrant and malignant.

Evidence Base

Limitations and Knowledge Gaps

1. Reduced penetrance and VUS burden: ~0.5% population carrier frequency with ~20% penetrance and ~54% VUS rate in panels complicate individual risk prediction and genetic counseling.
2. Gene-elusive disease: A substantial fraction of clinically definite ARVC lacks an identified pathogenic variant, limiting cascade screening in those families.
3. Risk stratification imperfection: The 2019 risk calculator underperforms in non-classical/left-dominant ACM; ringlike LGE and other markers add value but are not fully integrated.
4. Palliative therapeutics: No approved disease-modifying therapy currently exists; gene therapies remain preclinical/early-phase.
5. Causality of inflammation/autoantibodies: Whether inflammation initiates or merely amplifies disease — and whether anti-DSG2 autoantibodies are causal — remains incompletely established.
6. Quality-of-life data: Formal per-phenotype QoL instrument data (EQ-5D/SF-36) for ARVC were not identified in this investigation.
7. Model limitations: Murine models incompletely capture exercise-dependent, slowly progressive, and hot-phase human features.

Proposed Follow-up Experiments / Actions

1. Advance AAV gene therapies to clinical trials — track PKP2 replacement (LX2020) and mutation-agnostic Cx43 restoration; monitor ClinicalTrials.gov for first-in-human data.
2. Prospective validation of multimodal + ML risk models integrating CMR LGE (including ringlike pattern), FT-CMR strain, electroanatomic scar, and circulating miRNAs to improve the ARVC risk calculator, especially for left-dominant/biventricular phenotypes.
3. Test targeted small molecules (parthenolide, GSK-3β inhibitors, apremilast) and immunomodulation during hot phases in controlled preclinical and early-phase human studies.
4. Deep-phenotype gene-elusive families with WGS, structural-variant, and non-coding analyses; adopt broad cardiomyopathy/arrhythmia panels as standard.
5. Functionally reclassify VUS using hiPSC-CM and high-throughput assays to reduce diagnostic uncertainty.
6. Longitudinal exercise-dose studies to define safe activity thresholds by genotype and sex.
7. Collect standardized QoL/PROM data (EQ-5D, SF-36, ICD-specific measures) across ARVC registries.

References (selected PMIDs)

42366226, 42244336, 40202346, 25894016, 42305082, 40470644, 24276085, 34191271, 30790397, 25616645, 16722579, 21397041, 36635648, 36720007, 41582809, 42219531, 41185038, 40540101, 38512728, 32032135, 24996808, 41608798, 23392584, 40222719, 33927217, 33197325, 39009076, 42389803, 40383406, 42353884, 24598986, 28960618, 33343648, 33829244, 42159538, 31028357, 36289882, 40175378, 41759869, 42193878, 41448261, 41255689, 42366968, 38031154, 35152298, 24792740, 24515411, 28215569, 38206263, 41918562, 41884351, 34970070, 38892395, 42137277, 39980788, 25824144, 30985088, 41301430

Artifacts

• OpenScientist final report
• OpenScientist final report