The importance of variant reinterpretation in inherited cardiovascular diseases: Establishing the optimal timeframe.

Inherited cardiovascular diseases are rare diseases that are difficult to diagnose by non-expert professionals. Genetic analyses play a key role in the diagnosis of these diseases, in which the identification of a pathogenic genetic variant is often a diagnostic criterion. Therefore, genetic variant classification and routine reinterpretation as data become available represent one of the main challenges associated with genetic analyses. Using the genetic variants identified in an inherited cardiovascular diseases unit during a 10-year period, the objectives of this study were: 1) to evaluate the impact of genetic variant reinterpretation, 2) to compare the reclassification rates between different cohorts of cardiac channelopathies and cardiomyopathies, and 3) to establish the most appropriate periodicity for genetic variant reinterpretation. All the evaluated cohorts (full cohort of inherited cardiovascular diseases, cardiomyopathies, cardiac channelopathies, hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic cardiomyopathy, Brugada syndrome, long QT syndrome and catecholaminergic polymorphic ventricular tachycardia) showed reclassification rates above 25%, showing even higher reclassification rates when there is definitive evidence of the association between the gene and the disease in the cardiac channelopathies. Evaluation of genetic variant reclassification rates based on the year of the initial classification showed that the most appropriate frequency for the reinterpretation would be 2 years, with the possibility of a more frequent reinterpretation if deemed convenient. To keep genetic variant classifications up to date, genetic counsellors play a critical role in the reinterpretation process, providing clinical evidence that genetic diagnostic laboratories often do not have at their disposal and communicating changes in classification and the potential implications of these reclassifications to patients and relatives.

Implementing a New Algorithm for Reinterpretation of Ambiguous Variants in Genetic Dilated Cardiomyopathy.

Dilated cardiomyopathy is a heterogeneous entity that leads to heart failure and malignant arrhythmias. Nearly 50% of cases are inherited; therefore, genetic analysis is crucial to unravel the cause and for the early identification of carriers at risk. A large number of variants remain classified as ambiguous, impeding an actionable clinical translation. Our goal was to perform a comprehensive update of variants previously classified with an ambiguous role, applying a new algorithm of already available tools. In a cohort of 65 cases diagnosed with dilated cardiomyopathy, a total of 125 genetic variants were classified as ambiguous. Our reanalysis resulted in the reclassification of 12% of variants from an unknown to likely benign or likely pathogenic role, due to improved population frequencies. For all the remaining ambiguous variants, we used our algorithm; 60.9% showed a potential but not confirmed deleterious role, and 24.5% showed a potential benign role. Periodically updating the population frequencies is a cheap and fast action, making it possible to clarify the role of ambiguous variants. Here, we perform a comprehensive reanalysis to help to clarify the role of most of ambiguous variants. Our specific algorithms facilitate genetic interpretation in dilated cardiomyopathy.

Postmortem diagnosis of Takotsubo syndrome on autoptic findings: is it reliable? A systematic review.

Takotsubo syndrome (TTS) is a cardiac syndrome characterized by transient left ventricular systolic dysfunction in the absence of significant obstructive coronary artery disease. At the autopsy, its diagnosis is often challenging, since it is generally thought that it relates to no characteristic macroscopic or microscopic findings. In order to verify this last statement, we performed a systematic review of the literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA) criteria. To the best of our knowledge, it is the first systematic review addressing this issue. We identified recurring but not pathognomonic (microscopic) features of TTS: contraction band necrosis and non-specific inflammatory changes (e.g., interstitial infiltrates of mononuclear lymphocytes and macrophages) typically in the absence of microscopic findings typical of acute myocardial infarction. In cases of TTS-related sudden death, careful evaluation of anamnesis, autopsy data and post-mortem genetic results (to exclude other causes) should be considered to overcome the complexity of these cases.

LMNA-related muscular dystrophy: Identification of variants in alternative genes and personalized clinical translation.

Background: Laminopathies are caused by rare alterations in LMNA, leading to a wide clinical spectrum. Though muscular dystrophy begins at early ages, disease progression is different in each patient. We investigated variability in laminopathy phenotypes by performing a targeted genetic analysis of patients diagnosed with LMNA-related muscular dystrophy to identify rare variants in alternative genes, thereby explaining phenotypic differences. Methods: We analyzed 105 genes associated with muscular diseases by targeted sequencing in 26 pediatric patients of different countries, diagnosed with any LMNA-related muscular dystrophy. Family members were also clinically assessed and genetically analyzed. Results: All patients carried a pathogenic rare variant in LMNA. Clinical diagnoses included Emery-Dreifuss muscular dystrophy (EDMD, 13 patients), LMNA-related congenital muscular dystrophy (L-CMD, 11 patients), and limb-girdle muscular dystrophy 1B (LGMD1B, 2 patients). In 9 patients, 10 additional rare genetic variants were identified in 8 genes other than LMNA. Genotype-phenotype correlation showed additional deleterious rare variants in five of the nine patients (3 L-CMD and 2 EDMD) with severe phenotypes. Conclusion: Analysis f known genes related to muscular diseases in close correlation with personalized clinical assessments may help identify additional rare variants of LMNA potentially associated with early onset or most severe disease progression.

Reevaluation of ambiguous genetic variants in sudden unexplained deaths of a young cohort.

Sudden death cases in the young population remain without a conclusive cause of decease in almost 40% of cases. In these situations, cardiac arrhythmia of genetic origin is suspected as the most plausible cause of death. Molecular autopsy may reveal a genetic defect in up to 20% of families. Most than 80% of rare variants remain classified with an ambiguous role, impeding a useful clinical translation. Our aim was to update rare variants originally classified as of unknown significance to clarify their role. Our cohort included fifty-one post-mortem samples of young cases who died suddenly and without a definite cause of death. Five years ago, molecular autopsy identified at least one rare genetic alteration classified then as ambiguous following the American College of Medical Genetics and Genomics' recommendations. We have reclassified the same rare variants including novel data. About 10% of ambiguous variants change to benign/likely benign mainly because of improved population frequencies. Excluding cases who died before one year of age, almost 21% of rare ambiguous variants change to benign/likely benign. This fact makes it important to discard these rare variants as a cause of sudden unexplained death, avoiding anxiety in relatives' carriers. Twenty-five percent of the remaining variants show a tendency to suspicious deleterious role, highlighting clinical follow-up of carriers. Periodical reclassification of rare variants originally classified as ambiguous is crucial, at least updating frequencies every 5 years. This action aids to increase accuracy to enable and conclude a cause of death as well as translation into the clinic.

Eosinophilic Infiltration of the Sino-Atrial Node in Sudden Cardiac Death Caused by Long QT Syndrome.

Sudden death is defined as the unexpected death of a healthy person that occurs within the first hour of the onset of symptoms or within 24 h of the victim being last seen alive. In some of these cases, rare deleterious variants of genes associated with inherited cardiac disorders can provide a highly probable explanation for the fatal event. We report the case of a 21-year-old obese woman who lost consciousness suddenly in a public place and was pronounced dead after hospital admission. Clinical autopsy showed an inconclusive gross examination, while in the histopathological analysis an eosinophilic inflammatory focus and interstitial fibrosis in the sino-atrial node were found. Molecular autopsy revealed an intronic variant in the KCNQ1 gene (c.683 + 5G > A), classified as likely pathogenic for long QT syndrome according to the guidelines provided by the American College of Medical Genetics and Genomics. Therefore, there were many anomalies that could have played a role in the causation of the sudden death, such as the extreme obesity, the cardiac anomalies and the KNCQ1 variant. This case depicts the difficult interpretation of rare cardiac structural abnormalities in subjects carrying rare variants responsible for inherited arrhythmic disorders and the challenge for the forensic pathologist to make causal inferences in the determinism of the unexpected decease.

Unpredicted Aberrant Splicing Products Identified in Postmortem Sudden Cardiac Death Samples.

Molecular screening for pathogenic mutations in sudden cardiac death (SCD)-related genes is common practice for SCD cases. However, test results may lead to uncertainty because of the identification of variants of unknown significance (VUS) occurring in up to 70% of total identified variants due to a lack of experimental studies. Genetic variants affecting potential splice site variants are among the most difficult to interpret. The aim of this study was to examine rare intronic variants identified in the exonic flanking sequence to meet two main objectives: first, to validate that canonical intronic variants produce aberrant splicing; second, to determine whether rare intronic variants predicted as VUS may affect the splicing product. To achieve these objectives, 28 heart samples of cases of SCD carrying rare intronic variants were studied. Samples were analyzed using 85 SCD genes in custom panel sequencing. Our results showed that rare intronic variants affecting the most canonical splice sites displayed in 100% of cases that they would affect the splicing product, possibly causing aberrant isoforms. However, 25% of these cases (1/4) showed normal splicing, contradicting the in silico results. On the contrary, in silico results predicted an effect in 0% of cases, and experimental results showed >20% (3/14) unpredicted aberrant splicing. Thus, deep intron variants are likely predicted to not have an effect, which, based on our results, might be an underestimation of their effect and, therefore, of their pathogenicity classification and family members' follow-up.

Structural Heart Alterations in Brugada Syndrome: Is it Really a Channelopathy? A Systematic Review.

Brugada syndrome (BrS) is classified as an inherited cardiac channelopathy attributed to dysfunctional ion channels and/or associated proteins in cardiomyocytes rather than to structural heart alterations. However, hearts of some BrS patients exhibit slight histologic abnormalities, suggesting that BrS could be a phenotypic variant of arrhythmogenic cardiomyopathy. We performed a systematic review of the literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA) criteria. Our comprehensive analysis of structural findings did not reveal enough definitive evidence for reclassification of BrS as a cardiomyopathy. The collection and comprehensive analysis of new cases with a definitive BrS diagnosis are needed to clarify whether some of these structural features may have key roles in the pathophysiological pathways associated with malignant arrhythmogenic episodes.

Post-mortem toxicology analysis in a young sudden cardiac death cohort.

Risk of sudden cardiac death (SCD) increases with age, and several studies have examined the impact of different drugs on cardiovascular function. However, few studies have integrated epidemiological drug consumption data and genetic background in the context of cardiac death. We performed a retrospective population-based study in forensic sudden death cases from a 9-year period in Catalonia. The young cohort included 924 cases 18-50 years old, 566 of which had a cardiac cause of death. Complete autopsy, toxicological, and histopathological studies were performed. Molecular autopsy using next-generation sequencing was performed in nearly 400 cardiac cases. Cases related with fatal acute intoxication were excluded. Drug consumption prevalence was similar between forensic cases of cardiac and non-cardiac origin (62.5% versus 69.5%), with the exception of alcohol, which was more prevalent in the cardiac group than in the non-cardiac group (23.3% versus 17.1%). Individuals in the toxicology-positive group were carriers of more rare genetic variants and were significantly younger than the toxicology-negative group. Psychopharmacological drugs were identified in 22.3% of cardiac cases, and molecular autopsy identified an association between antiepileptic drugs or caffeine and pathogenic or likely pathogenic variants in arrhythmogenic genes. Specific substances could therefore play an essential role as triggers of SCD in genetically predisposed young people.

Rare variants in genes encoding structural myocyte contribute to a thickened ventricular septum in sudden death population without ventricular alterations.

Unexpected cardiac deaths are a current challenge to healthcare systems. In adults, coronary artery disease and acquired cardiomyopathies are the most frequent causes of sudden cardiac death while in younger than 35 years old, the main cause is represented by non-ischemic diseases, usually inherited. Nowadays, around 10%-15% of unexpected deaths remain without a definite cause of decease after a complete autopsy, then classified as deaths potentially due to an inherited arrhythmia. Discrete abnormalities in some of the heart measures have been considered as potential predictors or risk factors for sudden cardiac death. However, role of non-benign genetic variants in these scattered heart alterations remains to be clarified, especially if variants are classified of ambiguous role. Clinicians usually only take into consideration pathogenic variants for decision-making. It is yet unclear what the role of VUS genetic variants in modifying the anatomical parameters of the heart. We hypothesize that some heart measures might be influenced by polygenic components as some variants may individually confer minor risk but may actually produce additive effects when combined with others. Our aim was to investigate whether carrying non-benign rare variants in genes related to inherited arrhythmias may contribute to scattered cardiac alterations in anatomical normal hearts. The study is composed by 761 samples collected from autopsies of SD suffered by adults from 18 to 50 years of age who occurred in Catalonia (Spain) in a 9-year period. Complete medico-legal autopsy was performed to determine the cause of death. Molecular autopsy was performed as part of our forensic protocol, including genes associated with inherited diseases.To evaluate the effect of genetic rare variants into hearts measures we performed a linear regression model and data were presented as regression. This study showed, for the first time, that rare variants, regardless of significance (pathogenic, probably pathogenic or uncertain significance), may contribute to interventricular septum width in the structurally normal heart. While the cohort is based on sudden death cases, further studies and case-control studies will be necessary to conclude that the genetic determinants of septal thickness contributes to sudden cardiac death. We conclude that non-benign rare variants contribute to modify scattered septum width in structural normal hearts, being a potential risk factor of arrhythmia in genetic harbors. These evidence support the current recommendation in forensic protocols of including histologic analysis of septum when inherited arrhythmogenic disease is suspicious cause of decease.

Discerning the Ambiguous Role of Missense TTN Variants in Inherited Arrhythmogenic Syndromes.

The titin gene (TTN) is associated with several diseases, including inherited arrhythmias. Most of these diagnoses are attributed to rare TTN variants encoding truncated forms, but missense variants represent a diagnostic challenge for clinical genetics. The proper interpretation of genetic data is critical for translation into the clinical setting. Notably, many TTN variants were classified before 2015, when the American College of Medical Genetics and Genomics (ACMG) published recommendations to accurately classify genetic variants. Our aim was to perform an exhaustive reanalysis of rare missense TTN variants that were classified before 2015, and that have ambiguous roles in inherited arrhythmogenic syndromes. Rare missense TTN variants classified before 2015 were updated following the ACMG recommendations and according to all the currently available data. Our cohort included 193 individuals definitively diagnosed with an inherited arrhythmogenic syndrome before 2015. Our analysis resulted in the reclassification of 36.8% of the missense variants from unknown to benign/likely benign. Of all the remaining variants, currently classified as of unknown significance, 38.3% showed a potential, but not confirmed, deleterious role. Most of these rare missense TTN variants with a suspected deleterious role were identified in patients diagnosed with hypertrophic cardiomyopathy. More than 35% of the rare missense TTN variants previously classified as ambiguous were reclassified as not deleterious, mainly because of improved population frequencies. Despite being inconclusive, almost 40% of the variants showed a potentially deleterious role in inherited arrhythmogenic syndromes. Our results highlight the importance of the periodical reclassification of rare missense TTN variants to improve genetic diagnoses and help increase the accuracy of personalized medicine.

Influencia del grado de anemia en el pronóstico de los pacientes de edad avanzada con insuficiencia cardíaca (Estudio SPAN-HF) / Influence of the degree of anaemia on the prognosis of older adults with heart failure (SPAN-HF study)

Objetivo:Evaluar si un valor óptimo de hemoglobina sostenido en los 3 meses posteriores al ingreso por descompensación de insuficiencia cardíaca (IC) reduce la morbimortalidad durante los 12 meses posteriores a un ingreso por IC aguda.Pacientes y método:Estudio retrospectivo de los 1408 pacientes mayores de 65 años incluidos en el registro RICA divididos en 3 grupos: sin anemia (grupo A), anemia recuperada (grupo B) y anemia persistente (grupo C), según los niveles de hemoglobina en el ingreso y a los 3 meses tras el alta. Se construyeron curvas de Kaplan-Meier, comparando los grupos mediante la prueba de log-rank y se realizó un modelo de regresión de Cox para analizar la supervivencia.Resultados:Se incluyeron 578 (41,1%), 299 (21,2%) y 531 (37,7%) en los grupos A, B y C, respectivamente. Registramos un total de 768 muertes y reingresos. Hubo 23 (4%), 12 (4%) y 49 (9,2%) (p=0,001) individuos que fallecieron debido a la IC, y 154 (27%), 73 (24%) y 193 (36%) (p<0,001) reingresaron por esta patología, respectivamente. Los pacientes con anemia persistente tuvieron un riesgo superior de fallecimiento (RR: 1,29; IC95% de 1,04-1,61; p=0,024) o reingreso (1,92; IC95% de 1,16-3,19; p=0,012) por IC.Conclusiones:La anemia persistente en los meses posteriores a un ingreso por IC aumenta la morbimortalidad en el año posterior.

Objective:To assess whether a sustained optimal haemoglobin value in the 3 months after admission for heart failure (HF) decompensation reduces morbidity and mortality during the 12 months after admission for acute HF.Patients and method:Retrospective study of the 1408 patients older than 65 years included in the RICA registry divided into 3 groups: no anaemia (group A), recovered anaemia (group B), and persistent anaemia (group C), according to haemoglobin levels on admission, and 3 months after discharge. Kaplan-Meier curves were constructed, comparing the groups using the log-rank test and a Cox regression model was performed to analyse survival.Results:578 (41.1%), 299 (21.2%) and 531 (37.7%) were included in groups A, B and C, respectively. We recorded a total of 768 deaths and readmissions. There were 23 (4%), 12 (4%) and 49 (9.2%), (p=.001) individuals who died due to HF and 154 (27%), 73 (24%) and 193 (36%) (P<.001) admissions for this pathology, respectively. Patients with persistent anaemia had a higher risk of death (RR 1.29, 95% CI 1.04-1.61, P=.024) or readmission (1.92, 95% CI 1.16-3, 19; P=.012) due to HF.Conclusions:Persistent anaemia in the months after admission for HF increases morbidity and mortality in the subsequent year. (AU)

Clinical impact of rare variants associated with inherited channelopathies: a 5-year update.

A proper interpretation of the pathogenicity of rare variants is crucial before clinical translation. Ongoing addition of new data may modify previous variant classifications; however, how often a reanalysis is necessary remains undefined. We aimed to extensively reanalyze rare variants associated with inherited channelopathies originally classified 5 years ago and its clinical impact. In 2016, rare variants identified through genetic analysis were classified following the American College of Medical Genetics and Genomics' recommendations. Five years later, we have reclassified the same variants following the same recommendations but including new available data. Potential clinical implications were discussed. Our cohort included 49 cases of inherited channelopathies diagnosed in 2016. Update show that 18.36% of the variants changed classification mainly due to improved global frequency data. Reclassifications mostly occurred in minority genes associated with channelopathies. Similar percentage of variants remain as deleterious nowadays, located in main known genes (SCN5A, KCNH2 and KCNQ1). In 2016, 69.38% of variants were classified as unknown significance, but now, 53.06% of variants are classified as such, remaining the most common group. No management was modified after translation of genetic data into clinics. After 5 years, nearly 20% of rare variants associated with inherited channelopathies were reclassified. This supports performing periodic reanalyses of no more than 5 years since last classification. Use of newly available data is necessary, especially concerning global frequencies and family segregation. Personalized clinical translation of rare variants can be crucial to management if a significant change in classification is identified.

[Influence of the degree of anaemia on the prognosis of older adults with heart failure (SPAN-HF study)]. / Influencia del grado de anemia en el pronóstico de los pacientes de edad avanzada con insuficiencia cardíaca (Estudio SPAN-HF).

OBJECTIVE: To assess whether a sustained optimal haemoglobin value in the 3 months after admission for heart failure (HF) decompensation reduces morbidity and mortality during the 12 months after admission for acute HF. PATIENTS AND METHOD: Retrospective study of the 1408 patients older than 65 years included in the RICA registry divided into 3 groups: no anaemia (group A), recovered anaemia (group B), and persistent anaemia (group C), according to haemoglobin levels on admission, and 3 months after discharge. Kaplan-Meier curves were constructed, comparing the groups using the log-rank test and a Cox regression model was performed to analyse survival. RESULTS: 578 (41.1%), 299 (21.2%) and 531 (37.7%) were included in groups A, B and C, respectively. We recorded a total of 768 deaths and readmissions. There were 23 (4%), 12 (4%) and 49 (9.2%), (p=.001) individuals who died due to HF and 154 (27%), 73 (24%) and 193 (36%) (P<.001) admissions for this pathology, respectively. Patients with persistent anaemia had a higher risk of death (RR 1.29, 95% CI 1.04-1.61, P=.024) or readmission (1.92, 95% CI 1.16-3, 19; P=.012) due to HF. CONCLUSIONS: Persistent anaemia in the months after admission for HF increases morbidity and mortality in the subsequent year.

Early Identification of Prolonged QT Interval for Prevention of Sudden Infant Death.

Introduction: Long QT syndrome is the main arrhythmogenic disease responsible for sudden death in infants, especially in the first days of life. Performing an electrocardiogram in newborns could enable early diagnosis and adoption of therapeutic measures focused on preventing lethal arrhythmogenic events. However, the inclusion of an electrocardiogram in neonatal screening protocols still remains a matter of discussion. To comprehensively analyse the potential clinical value of performing an electrocardiogram and subsequent follow-up in a cohort of newborns. Methods: Electrocardiograms were performed in 685 neonates within the first week of life. One year follow-up was performed if QTc > 450 ms identified. Comprehensive genetic analysis using massive sequencing was performed in all cases with QTc > 470 ms. Results: We identified 54 neonates with QTc > 450 ms/ <470 ms; all normalized QTc values within 6 months. Eight cases had QTc > 480 ms at birth and, if persistent, pharmacological treatment was administrated during follow-up. A rare variant was identified as the potential cause of long QT syndrome in five cases. Three cases showed a family history of sudden arrhythmogenic death. Conclusions: Our prospective study identifies 0.14% of cases with a definite long QT, supporting implementation of electrocardiograms in routine pediatric protocols. It is an effective, simple and non-invasive approach that can help prevent sudden death in neonates and their relatives. Genetic analyses help to unravel the cause of arrhythmogenic disease in diagnosing neonates. Further, clinical assessment and genetic analysis of relatives allowed early identification of family members at risk of arrhythmias helping to adopt preventive personalized measures.

Sudden Death without a Clear Cause after Comprehensive Investigation: An Example of Forensic Approach to Atypical/Uncertain Findings.

Sudden death (SD) is defined as the unexpected natural death occurred within an hour after the onset of symptoms or from the last moment the subject has been seen in a healthy condition. Brugada syndrome (BrS) is one of the most remarkable cardiac causes of SD among young people. We report the case of a 20-year-old man who suddenly died after reportedly having smoked cannabis. Autopsy, toxicology, and genetic testing were performed. Autopsy found a long and thick myocardial bridging (MB) at 2 cm from the beginning of the left anterior descending coronary artery. Furthermore, at the histopathological examination, fibrosis and disarray in myocardial area above the MB, fatty tissue in the right ventricle and fibrosis of the sino-atrial node area were found. Toxicology testing was inconclusive, while genetic testing found a rare missense variant of the TTN gene, classified as likely benign, and a variant of unknown significance in the SLMAP gene (a gene that can be associated with BrS). Hence, despite several atypical features were found, no inference on the cause of the death could be made under current evidence.

Analysis of Brugada syndrome loci reveals that fine-mapping clustered GWAS hits enhances the annotation of disease-relevant variants.

Genome-wide association studies (GWASs) are instrumental in identifying loci harboring common single-nucleotide variants (SNVs) that affect human traits and diseases. GWAS hits emerge in clusters, but the focus is often on the most significant hit in each trait- or disease-associated locus. The remaining hits represent SNVs in linkage disequilibrium (LD) and are considered redundant and thus frequently marginally reported or exploited. Here, we interrogate the value of integrating the full set of GWAS hits in a locus repeatedly associated with cardiac conduction traits and arrhythmia, SCN5A-SCN10A. Our analysis reveals 5 common 7-SNV haplotypes (Hap1-5) with 2 combinations associated with life-threatening arrhythmia-Brugada syndrome (the risk Hap1/1 and protective Hap2/3 genotypes). Hap1 and Hap2 share 3 SNVs; thus, this analysis suggests that assuming redundancy among clustered GWAS hits can lead to confounding disease-risk associations and supports the need to deconstruct GWAS data in the context of haplotype composition.

Malignant Arrhythmogenic Role Associated with RBM20: A Comprehensive Interpretation Focused on a Personalized Approach.

The RBM20 gene encodes the muscle-specific splicing factor RNA-binding motif 20, a regulator of heart-specific alternative splicing. Nearly 40 potentially deleterious variants in RBM20 have been reported in the last ten years, being found to be associated with highly arrhythmogenic events in familial dilated cardiomyopathy. Frequently, malignant arrhythmias can be a primary manifestation of disease. The early recognition of arrhythmic genotypes is crucial in avoiding lethal episodes, as it may have an impact on the adoption of personalized preventive measures. Our study performs a comprehensive update of data concerning rare variants in RBM20 that are associated with malignant arrhythmogenic phenotypes with a focus on personalized medicine.

Rare Variants Associated with Arrhythmogenic Cardiomyopathy: Reclassification Five Years Later.

Genetic interpretation of rare variants associated with arrhythmogenic cardiomyopathy (ACM) is essential due to their diagnostic implications. New data may relabel previous variant classifications, but how often reanalysis is necessary remains undefined. Five years ago, 39 rare ACM-related variants were identified in patients with features of cardiomyopathy. These variants were classified following the American College of Medical Genetics and Genomics' guidelines. In the present study, we reevaluated these rare variants including novel available data. All cases carried one rare variant classified as being of ambiguous significance (82.05%) or likely pathogenic (17.95%) in 2016. In our comprehensive reanalysis, the classification of 30.77% of these variants changed, mainly due to updated global frequencies. As in 2016, nowadays most variants were classified as having an uncertain role (64.1%), but the proportion of variants with an uncertain role was significantly decreased (17.95%). The percentage of rare variants classified as potentially deleterious increased from 17.95% to 23.07%. Moreover, 83.33% of reclassified variants gained certainty. We propose that periodic genetic reanalysis of all rare variants associated with arrhythmogenic cardiomyopathy should be undertaken at least once every five years. Defining the roles of rare variants may help clinicians obtain a definite diagnosis.

Ripening-related cell wall modifications in olive (Olea europaea L.) fruit: A survey of nine genotypes.

The production of olive (Olea europaea L.) is very important economically in many areas of the world, and particularly in countries around the Mediterranean basin. Ripening-associated modifications in cell wall composition and structure of fruits play an important role in attributes like firmness or susceptibility to infestations, rots and mechanical damage, but limited information on these aspects is currently available for olive. In this work, cell wall metabolism was studied in fruits from nine olive cultivars ('Arbequina', 'Argudell', 'Empeltre', 'Farga', 'Manzanilla', 'Marfil', 'Morrut', 'Picual' and 'Sevillenca') picked at three maturity stages (green, turning and ripe). Yields of alcohol-insoluble residue (AIR) recovered from fruits, as well as calcium content in fruit pericarp, decreased along ripening. Cultivar-specific diversity was observed in time-course change patterns of enzyme activity, particularly for those acting on arabinosyl- and galactosyl-rich pectin side chains. Even so, fruit firmness levels were associated to higher pectin methylesterase (PME) activity and calcium contents. In turn, fruit firmness correlated inversely with ascorbate content and with α-l-arabinofuranosidase (AFase) and ß-galactosidase (ß-Gal) activities, resulting in preferential loss of neutral sugars from cell wall polymers.