scholarly journals The Role of MicroRNAs in Arrhythmogenic Cardiomyopathy: Biomarkers or Innocent Bystanders of Disease Progression?

2020 ◽  
Vol 21 (17) ◽  
pp. 6434
Author(s):  
Maria Bueno Marinas ◽  
Rudy Celeghin ◽  
Marco Cason ◽  
Gaetano Thiene ◽  
Cristina Basso ◽  
...  
Keyword(s):  
Gene Expression Regulation ◽  
Phenotypic Variability ◽  
Incomplete Penetrance ◽  
Primary Role ◽  
Arrhythmogenic Cardiomyopathy ◽  
Small Noncoding Rnas ◽  
Early Disease Detection ◽  
Pathogenic Variants ◽  
Fatty Replacement ◽  
Genes Encoding

Arrhythmogenic cardiomyopathy (AC) is an inherited cardiac disease characterized by a progressive fibro-fatty replacement of the working myocardium and by life-threatening arrhythmias and risk of sudden cardiac death. Pathogenic variants are identified in nearly 50% of affected patients mostly in genes encoding for desmosomal proteins. AC incomplete penetrance and phenotypic variability advocate that other factors than genetics may modulate the disease, such as microRNAs (miRNAs). MiRNAs are small noncoding RNAs with a primary role in gene expression regulation and network of cellular processes. The implication of miRNAs in AC pathogenesis and their role as biomarkers for early disease detection or differential diagnosis has been the objective of multiple studies employing diverse designs and methodologies to detect miRNAs and measure their expression levels. Here we summarize experiments, evidence, and flaws of the different studies and hitherto knowledge of the implication of miRNAs in AC pathogenesis and diagnosis.

scholarly journals Quantitative Approach to Fragmented QRS in Arrhythmogenic Cardiomyopathy: From Disease towards Asymptomatic Carriers of Pathogenic Variants

2020 ◽  
Vol 9 (2) ◽  
pp. 545 ◽  
Author(s):  
Rob W. Roudijk ◽  
Laurens P. Bosman ◽  
Jeroen F. van der Heijden ◽  
Jacques M. T. de Bakker ◽  
Richard N. W. Hauer ◽  
...  
Keyword(s):  
Early Stage ◽  
Pathogenic Variant ◽  
Observer Agreement ◽  
Arrhythmogenic Cardiomyopathy ◽  
Fragmented Qrs ◽  
Early Disease Detection ◽  
Pathogenic Variants ◽  
Disease Penetrance ◽  
Ecg Leads ◽  
And Control

Fragmented QRS complexes (fQRS) are common in patients with arrhythmogenic cardiomyopathy (ACM). A new method of fQRS quantification may aid early disease detection in pathogenic variant carriers and assessment of prognosis in patients with early stage ACM. Patients with definite ACM (n = 221, 66%), carriers of a pathogenic ACM-associated variant without a definite ACM diagnosis (n = 57, 17%) and control subjects (n = 58, 17%) were included. Quantitative fQRS (Q-fQRS) was defined as the total amount of deflections in the QRS complex in all 12 electrocardiography (ECG) leads. Q-fQRS was scored by a single observer and reproducibility was determined by three independent observers. Q-fQRS count was feasible with acceptable intra- and inter-observer agreement. Q-fQRS count is significantly higher in patients with definite ACM (54 ± 15) and pathogenic variant carriers (55 ± 10) compared to controls (35 ± 5) (p < 0.001). In patients with ACM, Q-fQRS was not associated with sustained ventricular arrhythmia (p = 0.701) at baseline or during follow-up (p = 0.335). Both definite ACM patients and pathogenic variant carriers not fulfilling ACM diagnosis have a higher Q-fQRS than controls. This may indicate that increased Q-fQRS is an early sign of disease penetrance. In concealed and early stages of ACM the role of Q-fQRS for risk stratification is limited.

A Familial Case of a Whole Germline CDC73 Deletion Discordant for Primary Hyperparathyroidism

2019 ◽  
Vol 92 (1) ◽  
pp. 56-63
Author(s):  
Naomi Hatabu ◽  
Naho Katori ◽  
Takeshi Sato ◽  
Naonori Maeda ◽  
Eri Suzuki ◽  
...  
Keyword(s):  
Primary Hyperparathyroidism ◽  
Phenotypic Variability ◽  
Early Adulthood ◽  
Familial Case ◽  
Incomplete Penetrance ◽  
Heterozygous Deletion ◽  
Imaging Studies ◽  
Intact Pth ◽  
Pathogenic Variants ◽  
Pth Level

Introduction: Primary hyperparathyroidism (PHPT) occurs as part of familial syndromes, including CDC73-related disorders caused by germline pathogenic variants of the CDC73 gene, particularly in early adulthood. Herein, we report a familial case of a whole germline CDC73 deletion discordant for PHPT. Case Description: A 15-year-old boy was admitted to our hospital because of persistent nausea and vomiting. Laboratory tests showed hypercalcemia (13.6 mg/dL), hypophosphatemia (2.4 mg/dL), and elevated intact PTH level (149 pg/mL). Imaging studies showed an enlarged single parathyroid gland. Thus, the diagnosis of PHPT was made. Microarray analysis of peripheral blood DNA showed a 3.4-Mb heterozygous deletion of 1q31 encompassing 11 genes, including CDC73. Total thyroidectomy/parathyroidectomy was performed; histology was compatible with parathyroid adenoma without any evidence of malignancy. DNA sequencing of the removed adenoma confirmed a hemizygous nonsense variant in the CDC73 gene in a mosaic manner, which was potentially involved in parathyroid tumorigenesis as the “second hit.” Importantly, the same deletion was identified in his 52-year-old father who had an unremarkable medical history. Conclusions: These data clearly demonstrate the Knudson two-hit theory from a molecular viewpoint. Phenotypic variability and incomplete penetrance of CDC73-related disorders, even if caused by a gross deletion, should be noted in a clinical setting.

Coinheritance of 2 New Potentially Damaging Heterozygous COL7A1 Variants in a Family With Autosomal Dominant Epidermolysis Bullosa Pruriginosa

2018 ◽  
Vol 21 (6) ◽  
pp. 580-584
Author(s):  
Gordon I Hale ◽  
Marta C Cohen ◽  
Oliver W Quarrell ◽  
John A McGrath ◽  
Andrew G Messenger
Keyword(s):  
Epidermolysis Bullosa ◽  
Autosomal Dominant ◽  
Late Onset ◽  
Phenotypic Variability ◽  
Incomplete Penetrance ◽  
Histopathological Diagnosis ◽  
Delayed Presentation ◽  
Pathogenic Variants ◽  
Type Vii Collagen ◽  
Phenotypic And Genotypic Variability

Epidermolysis bullosa pruriginosa (EBP) is a rare subtype of EB which is characterized by intense pruritus with blistering and nodular or lichenoid lesions most prominent on the lower extremities. It is caused by variants in COL7A1 which encodes for type VII collagen. There is wide phenotypic and genotypic variability between affected individuals. We report 2 potentially pathogenic variants in COL7A1 occurring on the same allele in a family with EBP and autosomal dominant inheritance. Late-onset EBP and incomplete penetrance may lead to delayed presentation in affected family members with the same variants. The broad phenotypic variability seen in EBP suggests that further genotypic and environmental factors may influence presentation. Genetic and histopathological diagnosis is essential, given the considerable overlap with clinically similar presentations such as hypertrophic lichen planus.

scholarly journals Buccal Mucosa Cells as a Potential Diagnostic Tool to Study Onset and Progression of Arrhythmogenic Cardiomyopathy

2021 ◽  
Vol 23 (1) ◽  
pp. 57
Author(s):  
Helen E. Driessen ◽  
Stephanie M. van der Voorn ◽  
Mimount Bourfiss ◽  
Freyja H. M. van Lint ◽  
Ferogh Mirzad ◽  
...  
Keyword(s):  
Buccal Mucosa ◽  
Cardiac Tissue ◽  
Task Force ◽  
Arrhythmogenic Cardiomyopathy ◽  
Cardiac Tissues ◽  
Protein Levels ◽  
Pathogenic Variants ◽  
Buccal Mucosa Cells ◽  
Genes Encoding ◽  
The Individual

In arrhythmogenic cardiomyopathy (ACM) pathogenic variants are found in genes encoding desmosomal proteins and in non-desmosomal genes, such as phospholamban (PLN, p.Arg14del variant). Previous research showed that plakoglobin protein levels and localization in the cardiac tissue of ACM patients, and PLN p.Arg14del patients diagnosed with an ACM phenotype, are disturbed. Moreover, the effects of pathogenic variants in desmosomal genes are reflected in non-cardiac tissues like buccal mucosa cells (BMC) which could serve as a promising new and non-invasive tool to support diagnosis. We collected the BMC of 33 ACM patients, 17 PLN p.Arg14del patients and 34 controls, labelled the BMC with anti-plakoglobin antibodies at different concentrations, and scored their membrane labelling. We found that plakoglobin protein levels were significantly reduced in BMC obtained from diagnosed ACM patients and preclinical variant carriers when compared to controls. This effect was independent from age and sex. Moderate to strong correlations were found with the revised 2010 Task Force Criteria score which is commonly used for ACM diagnosis (rs = −0.67, n = 64, p < 0.0001 and rs = −0.71, n = 64, p < 0.0001). In contrast, plakoglobin scores in PLN p.Arg14del patients were comparable to controls (p > 0.209), which suggests differences in underlying etiology. However, for the individual diagnosis of the ‘classical’ ACM patient, this method might not be discriminative enough to distinguish true patients from variant carriers and controls, because of the high interindividual variability.

scholarly journals Cadherin 2-Related Arrhythmogenic Cardiomyopathy: Prevalence and Clinical Features

2021 ◽  
Author(s):  
Alice Ghidoni ◽  
Perry M. Elliott ◽  
Petros Syrris ◽  
Hugh Calkins ◽  
Cynthia A. James ◽  
...  
Keyword(s):  
Heart Failure ◽  
Clinical Features ◽  
Genetic Screening ◽  
Rare Variants ◽  
Family Members ◽  
Arrhythmogenic Cardiomyopathy ◽  
Cascade Screening ◽  
Pathogenic Variants ◽  
Fatty Replacement ◽  
The Right

Background - Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disease characterized by fibro-fatty replacement of the right and/or left ventricle, often causing ventricular dysfunction and life-threatening arrhythmias. Variants in desmosomal genes account for up to 60% of cases. Our objective was to establish the prevalence and clinical features of ACM stemming from pathogenic variants, in the non-desmosomal cadherin 2 ( CDH2 ), a novel genetic substrate of ACM. Methods - A cohort of 500 unrelated patients with a definite diagnosis of ACM and no disease-causing variants in the main ACM genes was assembled. Genetic screening of CDH2 was performed through next-generation or Sanger sequencing. Whenever possible, cascade screening was initiated in the families of CDH2 -positive probands, and clinical evaluation was assessed. Results - Genetic screening of CDH2 led to the identification of 7 rare variants: five, identified in 6 probands, were classified as pathogenic or likely pathogenic. The previously established p.D407N pathogenic variant was detected in 2 additional probands. Probands and family members with pathogenic/likely pathogenic variants in CDH2 were clinically evaluated, and along with previously published cases, altogether contributed to the identification of gene-specific features (13 cases from this cohort and 11 previously published, for a total of 9 probands and 15 family members). Ventricular arrhythmic events occurred in most CDH2 -positive subjects (20/24, 83%), while the occurrence of heart failure was rare (2/24, 8.3%). Among probands, sustained ventricular tachycardia and/or sudden cardiac death occurred in 5/9 (56%). Conclusions - In this worldwide cohort of previously genotype-negative ACM patients, the prevalence of probands with CDH2 pathogenic/likely pathogenic variants was 1.2% (6/500). Our data show that this cohort of CDH2 -ACM patients has a high incidence of ventricular arrhythmias, while evolution toward heart failure is rare.

scholarly journals New SHH and Known SIX3 Variants in a Series of Latin American Patients with Holoprosencephaly

2021 ◽  
pp. 1-15
Author(s):  
Viviane Freitas de Castro ◽  
Daniel Mattos ◽  
Flavia Martinez de Carvalho ◽  
Denise Pontes Cavalcanti ◽  
Milagros M. Duenas-Roque ◽  
...  
Keyword(s):  
Latin American ◽  
Sanger Sequencing ◽  
Phenotypic Variability ◽  
Phenotypic Expression ◽  
Driver Gene ◽  
Incomplete Penetrance ◽  
Phenotype Correlation ◽  
Pathogenic Variants ◽  
Facial Defects ◽  
Domain Conservation

Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the <i>SHH</i>, <i>SIX3</i>, <i>ZIC2</i>, and <i>TGIF1</i> genes explain ∼25% of the known causes of nonchromosomal HPE. We studied these 4 genes and clinically described 27 Latin American families presenting with nonchromosomal HPE. Three new <i>SHH</i> variants and a third known <i>SIX3</i> likely pathogenic variant found by Sanger sequencing explained 15% of our cases. Genotype-phenotype correlation in these 4 families and published families with identical or similar driver gene, mutated domain, conservation of residue in other species, and the type of variant explain the pathogenicity but not the phenotypic variability. Nine patients, including 2 with <i>SHH</i> pathogenic variants, presented benign variants of the <i>SHH</i>, <i>SIX3</i>, <i>ZIC2</i>, and <i>TGIF1</i> genes with potential alteration of splicing, a causal proposition in need of further studies. Finding more families with the same <i>SIX3</i> variant may allow further identification of genetic or environmental modifiers explaining its variable phenotypic expression.

scholarly journals Update on Genes Associated with Arrhythmogenic Cardiomyopathy

2020 ◽  
Author(s):  
Marta Vallverdú-Prats ◽  
Mireia Alcalde ◽  
Georgia Sarquella-Brugada ◽  
Sergi Cesar ◽  
Elena Arbelo ◽  
...  
Keyword(s):  
Rare Variants ◽  
Correct Diagnosis ◽  
Phenotypic Expression ◽  
Genetic Alterations ◽  
Left Ventricular ◽  
Incomplete Penetrance ◽  
Arrhythmogenic Cardiomyopathy ◽  
Young Males ◽  
Genes Encoding ◽  
The Right

Arrhythmogenic cardiomyopathy is a rare genetic entity characterized by progressive fibro-fatty replacement of myocardium leading to malignant arrhythmias, syncope, and sudden cardiac death. Mostly it affects the right ventricle, but cases have also been described with biventricular and even isolated left ventricular involvement. The disease affects mainly young males and arrhythmias are usually induced by exercise. Arrhythmogenic cardiomyopathy has a genetic origin and is basically caused by deleterious alterations in genes encoding desmosomal proteins, especially plakophilin-2. To date, more than 400 rare genetic alterations have been identified in 18 genes, mainly with autosomal dominant inheritance, but some recessive forms have also been reported (Naxos disease and Carvajal syndrome). A comprehensive genetic analysis identifies a rare variant as potential cause of the disease in around 60% of patients, suggesting the existence of unknown genes as well as other genome alterations not yet discovered. Genetic interpretation classifies some of these rare variants as ambiguous, playing an uncertain role in arrhythmogenic cardiomyopathy. This makes a proper translation of genetic data into clinical practice difficult. Moreover, incomplete penetrance and variable phenotypic expression makes it difficult to arrive at the correct diagnosis. In the present chapter, we focus on recent advances in the knowledge regarding the genetic basis of arrhythmogenic cardiomyopathy.

scholarly journals Phenotypic Variability of a Pathogenic PKP2 Mutation in an Italian Family Affected by Arrhythmogenic Cardiomyopathy and Juvenile Sudden Death: Considerations From Molecular Autopsy to Sport Restriction

2021 ◽  
Vol 8 ◽  
Author(s):  
Maria Pia Leone ◽  
Pietro Palumbo ◽  
Johan Saenen ◽  
Sandra Mastroianno ◽  
Stefano Castellana ◽  
...  
Keyword(s):  
Task Force ◽  
Phenotypic Variability ◽  
Genetic Disorder ◽  
Physical Exertion ◽  
Dominant Mode ◽  
Specific Gene ◽  
Incomplete Penetrance ◽  
Arrhythmogenic Cardiomyopathy ◽  
Cascade Screening ◽  
Molecular Autopsy

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder with an estimated prevalence between 1:2,000 and 1:5,000 and is characterized by the fibrofatty replacement of cardiomyocytes that predisposes to malignant arrhythmias, heart failure, and sudden cardiac death. The diagnosis is based on the 2010 Task Force Criteria including family history, electrocardiographic traits and arrhythmogenic pattern, specific gene mutations, and structural and/or histological abnormalities. Most ACMs display an autosomal dominant mode of inheritance often with incomplete penetrance and variable expressivity. Genetic screening of patients with ACM identifies pathogenic or likely pathogenic variants, prevalently in genes encoding the cardiac desmosome (PKP2, DSP, DSC2, DSG2, and JUP) or less frequently in non-desmosomal genes (CTNNA3, PLN, TMEM43, RYR2, SCN5A, CDH2, and DES).Methods: In the present study, we performed molecular autopsy in a boy who died suddenly during physical exertion. In addition to post-mortem examination, a DNA sample was analyzed with next-generation sequencing (NGS).Results: The genetic analysis revealed the presence of pathogenic heterozygous c.314del (p.Pro105Leufs*7) frameshift variant in the PKP2 gene. Cascade screening of family members allowed us to identify 12 mutation carriers and to intervene on subjects at risk, many of whom were athletes.Conclusions: Molecular autopsy can establish cardiogenetic diagnosis and allow appropriate preventative measures in high-risk relatives.

scholarly journals The pathogenic p.(R391G) ABCC6 displays incomplete penetrance implying the necessity of an interacting partner for the development of pseudoxanthoma elasticum

2020 ◽  
Author(s):  
Flora Szeri ◽  
Agnes Miko ◽  
Nastassia Navasiolava ◽  
Ambrus Kaposi ◽  
Shana Verschuere ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Pseudoxanthoma Elasticum ◽  
Reference Population ◽  
Pathogenic Variant ◽  
Ectopic Calcification ◽  
Incomplete Penetrance ◽  
Sequence Variant ◽  
Primary Role ◽  
Inorganic Pyrophosphate ◽  
Pathogenic Variants

AbstractABCC6 encodes a transmembrane transporter playing a primary role in the efflux of ATP from hepatocytes to the bloodstream. ATP is then cleaved to AMP and inorganic pyrophosphate, a major inhibitor of ectopic calcification. Pathogenic variants of ABCC6 cause pseudoxanthoma elasticum, a multisystemic recessive ectopic calcification disease of variable severity. One of the mechanisms influencing the heterogeneity of a disorder is the penetrance of pathogenic variants. The penetrance of a sequence variant shows the proportion of individuals developing the expected phenotype in the presence of the variant. Incomplete penetrance indicates that the disease does not develop in all the cases when the pathogenic variant is present. Here, we investigated whether incomplete penetrance participates in the heterogeneity of pseudoxanthoma elasticum. By integrating the clinical and genetic data of 590 patients, we created the largest European pseudoxanthoma elasticum cohort. We identified two incomplete penetrant pathogenic variants, p.(V787I) and p.(R391G), based on their allele frequencies in our cohort and in the European reference population of gnomAD. The detailed characterization of the frequent p.(R391G) pathogenic variant suggested only 2% penetrance with an unaltered severity of the clinical phenotype. Based on our biochemical analysis, we hypothesize that the variant becomes deleterious only if an interacting partner is mutated simultaneously. These data point to new molecular mechanisms by revealing the potential existence of the first interacting partner of ABCC6. Our data are important for genetic counseling of pseudoxanthoma elasticum, suggesting a much lower disease heritability of these pathogenic variants.

scholarly journals Whole-Exome Sequencing Identifies Pathogenic Variants in TJP1 Gene Associated With Arrhythmogenic Cardiomyopathy

2018 ◽  
Vol 11 (10) ◽  
Author(s):  
Marzia De Bortoli ◽  
Alex V. Postma ◽  
Giulia Poloni ◽  
Martina Calore ◽  
Giovanni Minervini ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Arrhythmogenic Cardiomyopathy ◽  
Pathogenic Variants ◽  
Whole Exome
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