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BackgroundAs availability of genomic testing grows, variant interpretation will increasingly be performed by genomic generalists, rather than domain-specific experts. Demand is rising for laboratories to accurately classify variants in inherited cardiac condition (ICC) genes, including as secondary findings.MethodsWe analyse evidence for inheritance patterns, allelic requirement, disease mechanism and disease-relevant variant classes for 65 ClinGen-curated ICC gene-disease pairs. We present this information for the first time in a structured dataset, CardiacG2P, and assess application in genomic variant filtering.ResultsFor 36/65 gene-disease pairs, loss-of-function is not an established disease mechanism, and protein truncating variants are not known to be pathogenic. Using CardiacG2P as an initial variant filter allows for efficient variant prioritisation whilst maintaining a high sensitivity for retaining pathogenic variants compared with two other variant filtering approaches.ConclusionsAccess to evidence-based structured data representing disease mechanism and allelic requirement aids variant filtering and analysis and is pre-requisite for scalable genomic testing.

Introduction In the last years, genetic testing for inherited cardiac conditions (ICCs) is expanded and evolved at an incredible rate. This tool may inform treatment options and lifestyle choices to avoid arrhythmia triggers. Furthermore, identifying the genetic underpinning of the disorder improves risk assessment for asymptomatic or pre-symptomatic family members. However, despite the large numbers of disease-causative genes identified in the last years, only 60% of the patients with a clinical diagnosis of ICCs carry a pathogenic or likely pathogenic variant. The remaining 40% of the cases have an inconclusive or ambiguous test caused by negative results or mainly by the identification of one or more variants of unknown significance (VUS). In this case, the test results are uninformative and clinically irrelevant, increasing uncertainty about medical management. Purpose We investigated whether a periodic re-evaluation of the detected VUS, using the American College of Medical Genetics and Genomics (ACMG) criteria, may impact the clinical setting of patients with suspected ICC and their family members. Methods We reevaluated 306 consecutive probands with suspected ICC undergoing genetic testing by next-generation sequencing using the Illumina TruSight Cardio Sequencing panel, from 2017 to 2021. Results Thirty-five percent of patients carried at least one variant in a gene associated with the phenotype. Of these, 94 had been previously classified as VUS and were not considered clinically actionable. After an average time of 36 months, they were reevaluated and 26.6% of the VUS were reclassified. In particular, 1 was downgraded to Benign and 24 were upgraded to Likely Pathogenic (16) or Pathogenic (8). According to the different phenotypes, the reclassification rate was 45.8% in Hypertrophic cardiomyopathy, 33.3% in Dilated cardiomyopathy, 27.3% in Arrhythmogenic cardiomyopathy, 12.5% in Brugada syndrome, and 50% in Long QT syndrome patients. This reclassification process allowed to recategorize 24 probands as clinically and molecularly diagnosed and to extend the genetic screening to their at-risk family members. Conclusions Given the extent of the clinical impact that genetic testing can have, these findings suggest that a periodic reevaluation of genetic test results, particularly VUS, should be a mandatory step in the ICC diagnostic workflow.

Background Acute myocarditis (AM) is a heart inflammatory disease that may also rarely occur as a complication of COVID-19 vaccines. Inflammation is involved in arrhythmogenic cardiomyopathy (ACM) pathogenesis. Little is known regarding the COVID-19 vaccines influence on ACM relapses. We present two cases of vaccine related AM revealing a pre-existent (silent) ACM. Cases presentation Table shows a summary of the patients’ main clinical characteristics. Discussion We presented 2 cases of arrhythmic myocarditis-like clinical presentation in patients without previous cardiovascular history, whose timing was temporally related to a dose of vaccine against COVID-19. Subsequent diagnostic workup suggested the possible presence of an underlying silent ACM. In our case series, tissue characterization provided by CMR played a fundamental role as a diagnostic tool, showing in all cases a prominent left ventricle involvement and identifying both the underlying ACM disease and the superimposed myocardial inflammation. We hypothesize that a vaccine-induced AM could have revealed the presence of a pre-existent ACM, on which an inflammatory acute phase triggered the arrhythmic manifestation. Conclusion Vaccine-induced AM could reveal the presence of a pre-existent ACM. Our report suggests that a high index of suspicion and a multidisciplinary approach is required, in order to continue the diagnostic process once the acute event has been resolved, as it may have fundamental implication in the patient management. Further studies are required to verify if some of the vaccine-triggered AM represent the ACM first manifestation.

Molecular genetic testing is an increasingly available test to support the clinical diagnosis of inherited cardiovascular diseases through identification of pathogenic gene variants and to make a preclinical genetic diagnosis among proband's family members (so-called "cascade family screening"). In athletes, the added value of molecular genetic testing is to assist in discriminating between physiological adaptive changes of the athlete's heart and inherited cardiovascular diseases, in the presence of overlapping phenotypic features such as ECG changes, imaging abnormalities or arrhythmias ("grey zone"). Additional benefits of molecular genetic testing in the athlete include the potential impact on the disease risk stratification and the implications for eligibility to competitive sports. This position statement of the Italian Society of Sports Cardiology aims to guide general sports medical physicians and sports cardiologists on clinical decision as why and when to perform a molecular genetic testing in the athlete, highlighting strengths and weaknesses for each inherited cardiovascular disease at-risk of sudden cardiac death during sport. The importance of early (preclinical) diagnosis to prevent the negative effects of exercise on phenotypic expression, disease progression and worsening of the arrhythmogenic substrate is also addressed.

The G4C2-repeat expansion in C9orf72 is the most common cause of frontotemporal dementia and of amyotrophic lateral sclerosis. The variability of age at onset and phenotypic presentations is a hallmark of C9orf72 disease. In this study, we aimed to identify modifying factors of disease onset in C9orf72 carriers using a family-based approach, in pairs of C9orf72 carrier relatives with concordant or discordant age at onset. Linkage and association analyses provided converging evidence for a locus on chromosome Xq27.3. The minor allele A of rs1009776 was associated with an earlier onset (P = 1 × 10−5). The association with onset of dementia was replicated in an independent cohort of unrelated C9orf72 patients (P = 0.009). The protective major allele delayed the onset of dementia from 5 to 13 years on average depending on the cohort considered. The same trend was observed in an independent cohort of C9orf72 patients with extreme deviation of the age at onset (P = 0.055). No association of rs1009776 was detected in GRN patients, suggesting that the effect of rs1009776 was restricted to the onset of dementia due to C9orf72. The minor allele A is associated with a higher SLITRK2 expression based on both expression quantitative trait loci (eQTL) databases and in-house expression studies performed on C9orf72 brain tissues. SLITRK2 encodes for a post-synaptic adhesion protein. We further show that synaptic vesicle glycoprotein 2 and synaptophysin, two synaptic vesicle proteins, were decreased in frontal cortex of C9orf72 patients carrying the minor allele. Upregulation of SLITRK2 might be associated with synaptic dysfunctions and drives adverse effects in C9orf72 patients that could be modulated in those carrying the protective allele. How the modulation of SLITRK2 expression affects synaptic functions and influences the disease onset of dementia in C9orf72 carriers will require further investigations. In summary, this study describes an original approach to detect modifier genes in rare diseases and reinforces rising links between C9orf72 and synaptic dysfunctions that might directly influence the occurrence of first symptoms.

Evidence for the role of the CACNA1C gene, which encodes for the α-subunit of the cardiac L-type calcium channel CaV1.2, as a cause of the BrS3 variant of Brugada syndrome (BrS) is contradictory.The purpose of this study was to define in a large BrS cohort the yield of molecular screening and to test whether appropriate patient selection could improve clinical utility.A total of 709 patients were included in this study. BrS probands (n = 563, consecutively referred) underwent CACNA1C sequencing. Two matched cohorts where defined: discovery cohort (n = 200) and confirmation cohort (n = 363). In addition, the clinical phenotypes of a matched SCN5A-positive BrS cohort (n = 146) were included for comparative genotype-phenotype correlation.In the discovery cohort, we identified 11 different rare variants in 9 patients; 10 of the variants (5%) were considered potentially causative based on their frequency in the general population. However, American College of Medical Genetics criteria were unable to classify the majority (80%) of them, which eventually were labeled as variants of unknown significance (VUS). Functional studies revealed a loss of function for 9 variants, pointing to a prevalence of CACNA1C causative variants in 4% of the discovery cohort. Genotype-phenotype correlation showed that pathogenic variants are significantly more frequent in patients with shorter QTc (12.9% vs 2.2% in patients with QTc390 ms).CACNA1C is an infrequent but definitive cause of BrS typically associated with short QT. Functional studies are highly relevant to improve variant interpretation.

The diagnosis of structural heart disease in athletes with ventricular arrhythmias (VAs) and an apparently normal heart can be very challenging. Several pieces of evidence demonstrate the importance of an extensive diagnostic work-up in apparently healthy young patients for the characterization of concealed cardiomyopathies. This study shows the various diagnostic levels and tools to help identify which athletes need deeper investigation in order to unmask possible underlying heart disease.

Background: The etiology of frontotemporal dementia (FTD) is poorly understood. To identify genes with predicted expression levels associated with FTD, we integrated summary statistics with external reference gene expression data using a transcriptome-wide association study approach. Methods: FUSION software was used to leverage FTD summary statistics (all FTD: n = 2154 cases, n = 4308 controls; behavioral variant FTD: n = 1337 cases, n = 2754 controls; semantic dementia: n = 308 cases, n = 616 controls; progressive nonfluent aphasia: n = 269 cases, n = 538 controls; FTD with motor neuron disease: n = 200 cases, n = 400 controls) from the International FTD-Genomics Consortium with 53 expression quantitative loci tissue type panels (n = 12,205; 5 consortia). Significance was assessed using a 5% false discovery rate threshold. Results: We identified 73 significant gene–tissue associations for FTD, representing 44 unique genes in 34 tissue types. Most significant findings were derived from dorsolateral prefrontal cortex splicing data (n = 19 genes, 26%). The 17q21.31 inversion locus contained 23 significant associations, representing 6 unique genes. Other top hits included SEC22B (a gene involved in vesicle trafficking), TRGV5, and ZNF302. A single gene finding (RAB38) was observed for behavioral variant FTD. For other clinical subtypes, no significant associations were observed. Conclusions: We identified novel candidate genes (e.g., SEC22B) and previously reported risk regions (e.g., 17q21.31) for FTD. Most significant associations were observed in dorsolateral prefrontal cortex splicing data despite the modest sample size of this reference panel. This suggests that our findings are specific to FTD and are likely to be biologically relevant highlights of genes at different FTD risk loci that are contributing to the disease pathology.

Aims Catecholaminergic polymorphic ventricular tachycardia (CPVT) and short QT syndrome (SQTS) are inherited arrhythmogenic disorders that can cause sudden death. Numerous genes have been reported to cause these conditions, but evidence supporting these gene–disease relationships varies considerably. To ensure appropriate utilization of genetic information for CPVT and SQTS patients, we applied an evidence-based reappraisal of previously reported genes. Methods and results Three teams independently curated all published evidence for 11 CPVT and 9 SQTS implicated genes using the ClinGen gene curation framework. The results were reviewed by a Channelopathy Expert Panel who provided the final classifications. Seven genes had definitive to moderate evidence for disease causation in CPVT, with either autosomal dominant (RYR2, CALM1, CALM2, CALM3) or autosomal recessive (CASQ2, TRDN, TECRL) inheritance. Three of the four disputed genes for CPVT (KCNJ2, PKP2, SCN5A) were deemed by the Expert Panel to be reported for phenotypes that were not representative of CPVT, while reported variants in a fourth gene (ANK2) were too common in the population to be disease-causing. For SQTS, only one gene (KCNH2) was classified as definitive, with three others (KCNQ1, KCNJ2, SLC4A3) having strong to moderate evidence. The majority of genetic evidence for SQTS genes was derived from very few variants (five in KCNJ2, two in KCNH2, one in KCNQ1/SLC4A3). Conclusions Seven CPVT and four SQTS genes have valid evidence for disease causation and should be included in genetic testing panels. Additional genes associated with conditions that may mimic clinical features of CPVT/SQTS have potential utility for differential diagnosis.

Hannu Laaksovirta konsortion jäsenenä. The Genomics England Research Consortium, The International ALS/FTD Genomics Consortium (iAFGC), The International FTD Genetics Consortium (IFGC), The International LBD Genomics Consortium (iLBDGC), The NYGC ALS Consortium, The PROSPECT Consortium,17 James B. Rowe,17 Luisa Benussi,18 Giuliano Binetti,18,19 Roberta Ghidoni,18 Edwin Jabbari,20,21 Coralie Viollet,22 Jonathan D. Glass,23 Andrew B. Singleton,24 Vincenzo Silani,25,26 Owen A. Ross,27 Mina Ryten,8,28,29 Ali Torkamani,30 Toshiko Tanaka,31 Luigi Ferrucci,31 Susan M. Resnick,32 We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40?64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington?s disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered. We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40?64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington?s disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered.

Background Inconsistent data support the role of CACNA1C as a disease-causing gene responsible for Brugada syndrome (BrS). As of today, the only gene consistently linked with BrS is SCN5A. Several CACNA1c genetic variants have been reported in association wirh BrS; however, due to the limited evidence, CACNA1C is not suggested for routine genetic screening for BrS. Purpose In this study, we carried out a systematic screening of CACNA1C gene, including a functional evaluation of the identified variants, in order to determine the yield of screening in a large series of BrS probands and to address the hypothesis that an appropriate clinical selection of patients would substantially improve the yield of genetic testing. Methods and results Overall 564 consecutive patients, referred for BrS genetic testing, were sequenced for CACNA1C gene. Patients were divided in two groups: discovery cohort (n=200 patients) and confirmation cohort (n=363 patients). Furthermore, analysis of the clinical phenotypes of a matched SCN5A positive BrS cohort (n=146) was included for phenotype characterization. In the discovery cohort we identified 11 different genetic variants of whom 2 (18%) were considered as potentially causative based on ACMG guidelines. However, a large proportion (81%) was classified as variants of unknown significance (VUS). Functional evaluation of the identified variants, including pathogenic and VUS, was assessed by patch-clamp and immunofluorescence studies. Re-evaluation of the variants, including functional studies results, indicated an increase of pathogenic or likely pathogenic variants (81%) getting a yield of screening of 5% in the discovery cohort. Results from the confirmation cohort confirmed a low rate of CACNA1C carriers with a yield of screening of 2.2%. Analysing the clinical phenotype of all CACNA1C carriers showed a significantly shorter QTc [371 ms ± 16 ms vs. 399±18 ms; p=0.000004]. Furthermore, the prevalence of CACNA1C variants was highest (12.9%) among patients with a QTc in the lowest quartile (QTc Conclusion We confirmed that CACNA1C variants are not a common cause of BrS, with a yield of screening of 2–5%. However, pathogenic variants are more frequent (12.5%) in patients with a shorter QTc, suggesting a genetic testing strategy in this subgroup of BrS patients. Furthermore, our data highlights the impact of robust functional studies to improve variant classification and reduce uncertainties. Funding Acknowledgement Type of funding source: None

Funder: QingLan Research Project of Jiangsu for Outstanding Young Teachers, Funder: Project funded by Postdoctoral Science Foundation of Xuzhou Medical University, Funder: Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) for Xuzhou Medical University, We employed Mendelian randomization (MR) to evaluate the causal relationship between leukocyte telomere length (LTL) and amyotrophic lateral sclerosis (ALS) with summary statistics from genome-wide association studies (n = ~ 38,000 for LTL and ~ 81,000 for ALS in the European population; n = ~ 23,000 for LTL and ~ 4,100 for ALS in the Asian population). We further evaluated mediation roles of lipids in the pathway from LTL to ALS. The odds ratio per standard deviation decrease of LTL on ALS was 1.10 (95% CI 0.93–1.31, p = 0.274) in the European population and 0.75 (95% CI 0.53–1.07, p = 0.116) in the Asian population. This null association was also detected between LTL and frontotemporal dementia in the European population. However, we found that an indirect effect of LTL on ALS might be mediated by low density lipoprotein (LDL) or total cholesterol (TC) in the European population. These results were robust against extensive sensitivity analyses. Overall, our MR study did not support the direct causal association between LTL and the ALS risk in neither population, but provided suggestive evidence for the mediation role of LDL or TC on the influence of LTL and ALS in the European population.

Background- Identification of variants of uncertain significance (VUSs) poses relevant challenges in counseling and managing patients. They have an unknown impact on health, making the genetic tests clinically irrelevant. Recent studies demonstrate that a routine reclassification analysis enables to reclassify from 20% to 80% of this type of variant, improving risk stratification. Purpose- We investigated whether, in the context of inherited cardiac conditions, a review of the updated literature, including new functional data, allele frequency (GnomAD) and segregation analysis may help in the variant reclassification. Methods- Retrospective review of all VUSs in genes associated with inherited cardiac conditions identified in our cardiogenetic clinic between 2016 and 2018. Results- Thirty-one VUSs, classified using ACMG guidelines, were identified in 26 cases with a confirmed or suspected diagnosis of inherited cardiovascular diseases, including Long QT syndrome, Brugada syndrome, Arrhythmogenic Cardiomyopathy and Hypertrophic Cardiomyopathy). Twentyfour variants were identified in well-defined causative genes (SCN5A, KCNQ1, KCNH2, KCNE1, DSP, DSG2, MYH7, TPM1, TNNI3, TNNT2, CACNA1C, MYL3) while the remaining variants were identified in minor genes with limited evidence to support their disease causation as, ANK2 and AKAP9 gene. Preliminary results of the reclassification analysis showed that two variants were downgraded to likely benign (LB) applying the BS1 criterion (allele frequency) and 4 variants were upgraded to likely pathogenic (LP) according to novel published data and family segregation studies. Moreover, further studies to assess cosegregation in other variants are still ongoing. Conclusion- Based on our experience, 25% of variants of uncertain significance in well-defined causative genes, identified in patients with a confirmed or suspected diagnosis of inherited cardiovascular disease, were reclassified. These findings suggest that re-evaluation of genetic test results should be performed routinely in all diagnostic labs, in order to improve risk stratification and identification of family members at high risk.

Supplemental Digital Content is available in the text., Background: Long QT syndrome (LQTS) is the first described and most common inherited arrhythmia. Over the last 25 years, multiple genes have been reported to cause this condition and are routinely tested in patients. Because of dramatic changes in our understanding of human genetic variation, reappraisal of reported genetic causes for LQTS is required. Methods: Utilizing an evidence-based framework, 3 gene curation teams blinded to each other’s work scored the level of evidence for 17 genes reported to cause LQTS. A Clinical Domain Channelopathy Working Group provided a final classification of these genes for causation of LQTS after assessment of the evidence scored by the independent curation teams. Results: Of 17 genes reported as being causative for LQTS, 9 (AKAP9, ANK2, CAV3, KCNE1, KCNE2, KCNJ2, KCNJ5, SCN4B, SNTA1) were classified as having limited or disputed evidence as LQTS-causative genes. Only 3 genes (KCNQ1, KCNH2, SCN5A) were curated as definitive genes for typical LQTS. Another 4 genes (CALM1, CALM2, CALM3, TRDN) were found to have strong or definitive evidence for causality in LQTS with atypical features, including neonatal atrioventricular block. The remaining gene (CACNA1C) had moderate level evidence for causing LQTS. Conclusions: More than half of the genes reported as causing LQTS have limited or disputed evidence to support their disease causation. Genetic variants in these genes should not be used for clinical decision-making, unless accompanied by new and sufficient genetic evidence. The findings of insufficient evidence to support gene-disease associations may extend to other disciplines of medicine and warrants a contemporary evidence-based evaluation for previously reported disease-causing genes to ensure their appropriate use in precision medicine.

Ventricular arrhythmias (VAs) are the most common cause of death in athletes. The differences in the electroanatomic substrate in athletes and nonathletes with complex VA are unknown.The purpose of this study was to compare the electroanatomic substrate of complex VA in athletes vs nonathletes.The study prospectively enrolled young athletes and nonathletes with VA. Patients underwent 2-dimensional echocardiography, cardiac magnetic resonance (CMR) imaging, coronary angiography, 3-dimensional electroanatomic mapping (3D-EAM), and 3D-EAM-guided endomyocardial biopsy (EMB). Follow-up included 24-hour electrocardiographic Holter or implantable cardioverter-defibrillator/loop recorder interrogation for VA recurrence.Thirty-three patients were enrolled: 18 competitive athletes (56%) and 15 nonathletes (44%). Left ventricular and right ventricular (RV) findings by echocardiography and CMR did not show structural disease. Nine athletes (50%) were asymptomatic compared to 1 nonathlete (7%; P.05). Unifocal origin of VA was reported in 14 athletes (93%) and 17 nonathletes (94%). Athletes showed a larger RV unipolar than bipolar scar (18 ± 17 cmThis study showed the need for extensive diagnostic workup in apparently healthy young patients with complex VA in order to characterize concealed cardiomyopathies.

Background Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death, but its progression over time and predictors of arrhythmias are still being defined. Objectives This study sought to describe the clinical course of ARVC and occurrence of life-threatening arrhythmic events (LAE) and cardiovascular mortality; identify risk factors associated with increased LAE risk; and define the response to therapy. Methods We determined the clinical course of 301 consecutive patients with ARVC using the Kaplan-Meier method adjusted to avoid the bias of delayed entry. Predictors of LAE over 5.8 years of follow-up were determined with Cox multivariable analysis. Treatment efficacy was assessed comparing LAE rates during matched time intervals. Results A first LAE occurred in 1.5 per 100 person-years between birth and age 20 years, in 4.0 per 100 person-years between ages 21 and 40 years, and in 2.4 per 100 person-years between ages 41 and 60 years. Cumulative probability of a first LAE at follow-up was 14% at 5 years, 23% at 10 years, and 30% at 15 years. Higher risk of LAE was predicted by atrial fibrillation (hazard ratio [HR]: 4.38; p = 0.002), syncope (HR: 3.36; p Conclusions The high risk of life-threatening arrhythmias in patients with ARVC spans from adolescence to advanced age, reaching its peak between ages 21 and 40 years. Atrial fibrillation, syncope, participation in strenuous exercise after the diagnosis of ARVC, hemodynamically tolerated sustained monomorphic ventricular tachycardia, and male sex predicted lethal arrhythmias at follow-up. The lack of efficacy of antiarrhythmic therapy and the life-saving role of the implantable cardioverter-defibrillator highlight the importance of risk stratification for patient management.

ATENCIÓ: la correcció està també al DDD, cal relacionar??? https://ddd.uab.cat/record/226203 Altres ajuts: The following studies and consortia have contributed to this manuscript. Amsterdam dementia Cohort (ADC): Research of the Alzheimer center Amsterdam is part of the neurodegeneration research program of Amsterdam Neuroscience. The Alzheimer Center Amsterdam is supported by Stichting Alzheimer Nederland and Stichting VUmc fonds. The clinical database structure was developed with funding from Stichting Dioraphte. Genotyping of the Dutch case-control samples was performed in the context of EADB (European Alzheimer DNA biobank) funded by the JPco-fuND FP-829-029 (ZonMW projectnumber 733051061). 100-Plus study: We are grateful for the collaborative efforts of all participating centenarians and their family members and/or relations. This work was supported by Stichting Alzheimer Nederland (WE09.2014-03), Stichting Diorapthe, horstingstuit foundation, Memorabel (ZonMW projectnumber 733050814) and Stichting VUmc Fonds. Genotyping of the 100-Plus Study was performed in the context of EADB (European Alzheimer DNA biobank) funded by the JPco-fuND FP-829-029 (ZonMW projectnumber 733051061). German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe): This study/publication is part of the German Research Network on Dementia (KND), the German Research Network on Degenerative Dementia (KNDD; German Study on Ageing, Cognition and Dementia in Primary Care Patients; AgeCoDe), and the Health Service Research Initiative (Study on Needs, health service use, costs and health-related quality of life in a large sample of oldest-old primary care patients (85+; AgeQualiDe)) and was funded by the German Federal Ministry of Education and Research (grants KND: 01GI0102, 01GI0420, 01GI0422, 01GI0423, 01GI0429, 01GI0431, 01GI0433, 01GI0434; grants KNDD: 01GI0710, 01GI0711, 01GI0712, 01GI0713, 01GI0714, 01GI0715, 01GI0716; grants Health Service Research Initiative: 01GY1322A, 01GY1322B, 01GY1322C, 01GY1322D, 01GY1322E, 01GY1322F, 01GY1322G). Alfredo Ramirez was partly supported by the ADAPTED consortium: Alzheimer's disease Apolipoprotein Pathology for Treatment Elucidation and Development, which has received funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 115975. Brain compendium: This work was funded by the UK Medical Research Council (13044). P.F.C. is a Wellcome Trust principal Fellow (212219/Z/18/Z) and a UK NIHR Senior Investigator, who receives support from the Medical Research Council Mitochondrial Biology Unit (MC_UU_00015/9), and the National Institute for Health Research (NIHR) Biomedical Research Centre based at Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health.Clinical AD, Sweden: We would like to thank UCL Genomics for performing the genotyping analyses. Danish data: The studies behind the Danish long-lived cases received funding from The National Program for Research Infrastructure 2007 (grant no. 09-063256), the Danish Agency for Science Technology and Innovation, the Velux Foundation, the US National Institute of Health (P01 AG08761), the Danish Agency for Science, Technology and Innovation/The Danish Council for Independent Research (grant no. 11-107308), the European Union's Seventh Framework Programme (FP7/2007-2011) under grant agreement no. 259679, the INTERREG 4 A programme Syddanmark-Schleswig-K.E.R.N. (by EU funds from the European Regional Development Fund), the CERA Foundation (Lyon), the AXA Research Fund, Paris, and The Health Foundation (Helsefonden), Copenhagen, Denmark. The GOYA study was conducted as part of the activities of the Danish Obesity Research Centre (DanORC, www.danorc.dk) and The MRC centre for Causal Analyses in Translational Epidemiology (MRC CAiTE). The genotyping for GOYA was funded by the Wellcome Trust (WT 084762). GOYA is a nested study within The Danish National Birth Cohort which was established with major funding from the Danish National Research Foundation. Additional support for this cohort has been obtained from the Pharmacy Foundation, the Egmont Foundation, The March of Dimes Birth Defects Foundation, the Augustinus Foundation, and the Health Foundation. Fundació ACE (FACE): We would like to thank patients and controls who participated in this project. We are indebted to Trinitat Port-Carbó and her family for their support of Fundació ACE research programs. Fundació ACE collaborates with the Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, Spain) and is one of the participating centers of the Dementia Genetics Spanish Consortium (DEGESCO). Agustín Ruiz has received support from the EU/EFPIA Innovative Medicines Initiative Joint Undertaking ADAPTED Grant No. 115975 and by grants PI13/02434 and PI16/01861. Acción Estratégica en Salud, integrated in the Spanish National R + D + I Plan and financed by ISCIII (Instituto de Salud Carlos III)-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER- "Una manera de Hacer Europa"), by Fundación bancaria "La Caixa" and Grifols SA (GR@ACE project). Genetics of Healthy Ageing Study (GEHA - NL): The work described in this paper was funded mainly by the EU GEHA Project contract no. LSHM-CT-2004-503-270. Gothenburg Birth Cohort (GBC) Studies: We would like to thank UCL Genomics for performing the genotyping analyses. The studies were supported by The Stena Foundation, The Swedish Research Council (2015-02830, 2013-8717), The Swedish Research Council for Health, Working Life and Wellfare (2013-1202, 2005-0762, 2008-1210, 2013-2300, 2013-2496, 2013-0475), The Brain Foundation, Sahlgrenska University Hospital (ALF), The Alzheimer's Association (IIRG-03-6168), The Alzheimer's Association Zenith Award (ZEN-01-3151), Eivind och Elsa K:son Sylvans Stiftelse, The Swedish Alzheimer Foundation. International FTD-Genomics Consortium (IFGC): International FTD-Genomics Consortium (IFGC): The authors thank the IFGC for providing relevant data to support the analyses presented in this manuscript. Further acknowledgments for IFGC (https://ifgcsite.wordpress.com/), e.g. full members list and affiliations, are found in the online supplementary files. IPDGC (​The International Parkinson Disease Genomics Consortium): We also would like to thank all members of the International Parkinson Disease Genomics Consortium (IPDGC). See for a complete overview of members, acknowledgements and funding http://pdgenetics.org/partners. Kompetenznetz Multiple Sklerose (KKNMS): This work was supported by the German Ministry for Education and Research (BMBF) as part of the "German Competence Network Multiple Sclerosis" (KKNMS) (grant nos. 01GI0916 and 01GI0917) and the Munich Cluster for Systems Neurology (SyNergy). TA was supported by the BMBF through the Integrated Network IntegraMent, under the auspices of the e:Med Programme (01ZX1614J). BH was supported by the EU Horizon 2020 project MultipleMS.Longitudinal Aging Study Amsterdam (LASA) is largely supported by a grant from the Netherlands Ministry of Health, Welfare and Sports, Directorate of Long-Term Care. The authors are grateful to all LASA participants, the fieldwork team and all researchers for their ongoing commitment to the study. Leiden Longevity Study: This study was supported by a grant from the Innovation-Oriented Research Program on Genomics (SenterNovem IGE05007), the Centre for Medical Systems Biology, and the Netherlands Consortium for Healthy Ageing (Grant 050-060-810), all in the framework of the Netherlands Genomics Initiative/Netherlands Organization for Scientific Research (NWO) and by Unilever Colworth.Maria Carolina Dalmasso: Georg Forster Research Award (Alexander von Humboldt Foundation). Mayo Clinic AD, DLB, PD, PSP: We thank the patients and their families for their participation, without whom these studies would not have been possible. Funding for this work was supported by National Institute on Aging [RF AG051504 to NET.; U01 AG046139 to NET]; and National Institute of Neurological Disorders and Stroke [R01 NS080820 to NET; P50 NS072187]. The Mayo Clinic is a Lewy Body Dementia Association (LBDA) Research Center of Excellence, American Parkinson Disease Association (APDA) Information and Referral Center and Center for Advanced Research, NINDS Tau Center without Walls (U54-NS100693) and is supported by Mayo Clinic AD and related dementias genetics program, The Little Family Foundation, the Mangurian Foundation for Lewy body research and NINDS R01 NS078086 (to OAR). The PD program at the Mayo Clinic Florida is also supported by the Mayo Clinic Center for Regenerative Medicine, Mayo Clinic Center for Individualized Medicine, Mayo Clinic Neuroscience Focused Research Team (Cecilia and Dan Carmichael Family Foundation, and the James C. and Sarah K. Kennedy Fund for Neurodegenerative Disease Research at Mayo Clinic in Florida), the gift from Carl Edward Bolch, Jr., and Susan Bass Bolch, and The Sol Goldman Charitable Trust. Samples included in this study are from the brain bank at Mayo Clinic in Jacksonville which is supported by CurePSP The online version of this article (10.1007/s00401-019-02026-8) contains supplementary material, which is available to authorized users.

Plakophilin-2 (PKP2) is a component of the desmosome complex and known for its role in cell-cell adhesion. Recently, alterations in the Pkp2 gene have been associated with different inherited cardiac conditions including Arrythmogenic Cardiomyopathy (ACM or ARVC), Brugada syndrome (BrS), and idiopathic ventricular fibrillation to name the most relevant. However, the assessment of pathogenicity regarding the genetic variations associated with Pkp2 is still a challenging task: the gene has a positive Residual Variation Intolerance Score and the potential deleterious role of several of its variants has been disputed. Limitations in facilitating interpretation and annotations of these variants are seen in the lack of segregation and clinical data in the control population of reference. In this review, we will provide a summary of all the currently available genetic information related to the Pkp2 gene, including different phenotypes, ClinVar annotations and data from large control database. Our goal is to provide a literature review that could help clinicians and geneticists in interpreting the role of Pkp2 variants in the context of heritable sudden death syndromes. Limitations of current algorithms and data repositories will be discussed.

Mutations in the microtubule-associated protein tau (MAPT) gene cause autosomal dominant frontotemporal lobar degeneration with tau inclusions (FTLD-tau). MAPT p.R406W carriers present clinically with progressive memory loss and neuropathologically with neuronal and glial tauopathy. However, the pathogenic events triggered by the expression of the mutant tau protein remain poorly understood. To identify the genes and pathways that are dysregulated in FTLD-tau, we performed transcriptomic analyses in induced pluripotent stem cell (iPSC)–derived neurons carrying MAPT p.R406W and CRISPR/Cas9-corrected isogenic controls. We found that the expression of the MAPT p.R406W mutation was sufficient to create a significantly different transcriptomic profile compared with that of the isogeneic controls and to cause the differential expression of 328 genes. Sixty-one of these genes were also differentially expressed in the same direction between MAPT p.R406W carriers and pathology-free human control brains. We found that genes differentially expressed in the stem cell models and human brains were enriched for pathways involving gamma-aminobutyric acid (GABA) receptors and pre-synaptic function. The expression of GABA receptor genes, including GABRB2 and GABRG2, were consistently reduced in iPSC-derived neurons and brains from MAPT p.R406W carriers. Interestingly, we found that GABA receptor genes, including GABRB2 and GABRG2, are significantly lower in symptomatic mouse models of tauopathy, as well as in brains with progressive supranuclear palsy. Genome wide association analyses reveal that common variants within GABRB2 are associated with increased risk for frontotemporal dementia (P −3). Thus, our systems biology approach, which leverages molecular data from stem cells, animal models, and human brain tissue can reveal novel disease mechanisms. Here, we demonstrate that MAPT p.R406W is sufficient to induce changes in GABA-mediated signaling and synaptic function, which may contribute to the pathogenesis of FTLD-tau and other primary tauopathies.

Background Long QT syndrome type 3 (LQT3) is a lethal disease caused by gain-of-function mutations in the SCN5A gene, coding for the alpha-subunit of the sodium channel NaV1.5. Mexiletine is used to block late sodium current and to shorten QT interval in LQT3 patients. Objectives The aim of this study was to determine whether mexiletine prevents arrhythmic events (arrhythmic syncope, aborted cardiac arrest, or sudden cardiac death) in LQT3 patients. Methods The endpoint of this retrospective cohort study, which studied consecutive LQT3 patients who were referred to our center and treated with mexiletine, was to evaluate the antiarrhythmic efficacy of mexiletine by comparing the number of arrhythmic events per patient and the annual rate of arrhythmic events during observation periods of equal duration before and after the beginning of therapy with mexiletine. Results The study population comprised 34 LQT3 patients, 19 (56%) of whom were male. The median age at beginning of treatment with mexiletine was 22 years, and median QTc interval before therapy 509 ms. The median duration of oral mexiletine therapy was 36 months, at an average daily dose of 8 ± 0.5 mg/kg. Mexiletine significantly shortened QTc (by 63 ± 6 ms; p < 0.0001) and reduced the percentage of patients with arrhythmic events (from 22% to 3%; p = 0.031), the mean number of arrhythmic events per patient (from 0.43 ± 0.17 to 0.03 ± 0.03; p = 0.027), and the annual rate of arrhythmic events (from 10.3% to 0.7%; p = 0.0097). Conclusions Besides shortening QTc interval, mexiletine caused a major reduction of life-threatening arrhythmic events in LQT3 patients, thus representing an efficacious therapeutic strategy.

Long QT syndrome (LQTS) is one the best characterized disorders among all inherited arrhythmogenic syndromes. A multi-parametric risk stratification scheme, which includes clinical variables (QTc, gender) and the main LQTS genotypes, was defined in the early 2000s and is currently used in clinical practice. However, the evidence of a marked phenotypic variability, even in the presence of the same genetic mutation has puzzled many investigators since the discovery of LQTS genes. Practically, variable expression in LQTS often limits the predictive accuracy of risk stratification markers. Therefore, in a subset of cases, the identification of subjects at a high risk of life-threatening arrhythmias and sudden death is difficult. The discovery of common genetic variants that explain the heritable components of the human electrocardiogram, including QT interval, generated the hypothesis that genetic modifiers may account for phenotypical variability in LQTS. Despite the fact that multiple SNPs have been linked to QT interval duration, clinical applications of any findings are limited by the small effect sizes conferred by single SNPs and incomplete knowledge on their functional consequences. Nevertheless, the possibility of introducing SNP genotyping in risk stratification schemes to improve patient-specificity is an attractive goal. Here we review the currently available evidence and future perspectives for the inclusion of genetic modifiers in the clinical management of LQTS.

On autopsy, a patient is found to have hypertrophic cardiomyopathy. The patient’s family pursues genetic testing that shows a “likely pathogenic” variant for the condition on the basis of a study in an original research publication. Given the dominant inheritance of the condition and the risk of sudden cardiac death, other family members are tested for the genetic variant to determine their risk. Several family members test negative and are told that they are not at risk for hypertrophic cardiomyopathy and sudden cardiac death, and those who test positive are told that they need to be regularly monitored for cardiomyopathy on echocardiography. Five years later, during a routine clinic visit of one of the genotype-positive family members, the cardiologist queries a database for current knowledge on the genetic variant and discovers that the variant is now interpreted as “likely benign” by another laboratory that uses more recently derived population-frequency data. A newly available testing panel for additional genes that are implicated in hypertrophic cardiomyopathy is initiated on an affected family member, and a different variant is found that is determined to be pathogenic. Family members are retested, and one member who previously tested negative is now found to be positive for this new variant. An immediate clinical workup detects evidence of cardiomyopathy, and an intracardiac defibrillator is implanted to reduce the risk of sudden cardiac death.

Background— Brugada syndrome (BrS) primarily associates with the loss of sodium channel function. Previous studies showed features consistent with sodium current ( I Na ) deficit in patients carrying desmosomal mutations, diagnosed with arrhythmogenic cardiomyopathy (or arrhythmogenic right ventricular cardiomyopathy). Experimental models showed correlation between the loss of expression of desmosomal protein plakophilin-2 (PKP2) and reduced I Na . We hypothesized that PKP2 variants that reduce I Na could yield a BrS phenotype, even without overt structural features characteristic of arrhythmogenic right ventricular cardiomyopathy. Methods and Results— We searched for PKP2 variants in the genomic DNA of 200 patients with a BrS diagnosis, no signs of arrhythmogenic cardiomyopathy, and no mutations in BrS-related genes SCN5A, CACNa1c, GPD1L , and MOG1. We identified 5 cases of single amino acid substitutions. Mutations were tested in HL-1–derived cells endogenously expressing Na V 1.5 but made deficient in PKP2 (PKP2-KD). Loss of PKP2 caused decreased I Na and Na V 1.5 at the site of cell contact. These deficits were restored by the transfection of wild-type PKP2, but not of BrS-related PKP2 mutants. Human induced pluripotent stem cell cardiomyocytes from a patient with a PKP2 deficit showed drastically reduced I Na . The deficit was restored by transfection of wild type, but not BrS-related PKP2. Super-resolution microscopy in murine PKP2-deficient cardiomyocytes related I Na deficiency to the reduced number of channels at the intercalated disc and increased separation of microtubules from the cell end. Conclusions— This is the first systematic retrospective analysis of a patient group to define the coexistence of sodium channelopathy and genetic PKP2 variations. PKP2 mutations may be a molecular substrate leading to the diagnosis of BrS.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death, but its progression over time and predictors of arrhythmias are still being defined.This study sought to describe the clinical course of ARVC and occurrence of life-threatening arrhythmic events (LAE) and cardiovascular mortality; identify risk factors associated with increased LAE risk; and define the response to therapy.We determined the clinical course of 301 consecutive patients with ARVC using the Kaplan-Meier method adjusted to avoid the bias of delayed entry. Predictors of LAE over 5.8 years of follow-up were determined with Cox multivariable analysis. Treatment efficacy was assessed comparing LAE rates during matched time intervals.A first LAE occurred in 1.5 per 100 person-years between birth and age 20 years, in 4.0 per 100 person-years between ages 21 and 40 years, and in 2.4 per 100 person-years between ages 41 and 60 years. Cumulative probability of a first LAE at follow-up was 14% at 5 years, 23% at 10 years, and 30% at 15 years. Higher risk of LAE was predicted by atrial fibrillation (hazard ratio [HR]: 4.38; p = 0.002), syncope (HR: 3.36; p 0.001), participation in strenuous exercise after the diagnosis (HR: 2.98; p = 0.028), hemodynamically tolerated sustained monomorphic ventricular tachycardia (HR: 2.19; p = 0.023), and male sex (HR: 2.49; p = 0.012). No difference was observed in the occurrence of LAE before and after treatment with amiodarone, beta-blockers, sotalol, or ablation. A total of 81 patients received an implantable cardioverter-defibrillator, 34 were successfully defibrillated.The high risk of life-threatening arrhythmias in patients with ARVC spans from adolescence to advanced age, reaching its peak between ages 21 and 40 years. Atrial fibrillation, syncope, participation in strenuous exercise after the diagnosis of ARVC, hemodynamically tolerated sustained monomorphic ventricular tachycardia, and male sex predicted lethal arrhythmias at follow-up. The lack of efficacy of antiarrhythmic therapy and the life-saving role of the implantable cardioverter-defibrillator highlight the importance of risk stratification for patient management.

Inherited arrhythmogenic diseases (IADs – also called cardiac channelopathies) are defined as a group of genetic diseases characterized by electrically unstable substrate in a structurally normal heart (1). Genetic testing in cardiac channelopathies has completed its transition from a research-based activity to that of a clinical genetic service. In parallel, the advancements of the sequencing technologies are providing ways to sequence several genes at a relatively low cost. This is progressively changing the approach to the genetic diagnosis of IADs. Indeed, while Sanger-based genetic testing was traditionally limited to the well characterized, most prevalent genes, next-generation sequencing (NGS) allows screening even the “minor” disease genes with very short turnaround time. This approach to genetic testing is highly efficient, but it is also generating remarkable interpretative problems mostly related to the high prevalence of variants of unknown significance (VUS), i.e., not clearly related to disease pathophysiology. This issue is relevant to several genetic diseases of the heart but is particularly evident in IADs, where the familial co-segregation analysis is hampered by the incomplete penetrance and the variable expressivity. How to design the most appropriate screening approach is challenging and it requires in-depth knowledge of the specific diseases of interest. In this Opinion article, we will review the available NGS approaches and try to outline the available strategies to optimize the performance of this genetic testing methodology.

Summary Background Frontotemporal dementia (FTD) is a complex disorder characterised by a broad range of clinical manifestations, differential pathological signatures, and genetic variability. Mutations in three genes— MAPT , GRN , and C9orf72 —have been associated with FTD. We sought to identify novel genetic risk loci associated with the disorder. Methods We did a two-stage genome-wide association study on clinical FTD, analysing samples from 3526 patients with FTD and 9402 healthy controls. To reduce genetic heterogeneity, all participants were of European ancestry. In the discovery phase (samples from 2154 patients with FTD and 4308 controls), we did separate association analyses for each FTD subtype (behavioural variant FTD, semantic dementia, progressive non-fluent aphasia, and FTD overlapping with motor neuron disease [FTD-MND]), followed by a meta-analysis of the entire dataset. We carried forward replication of the novel suggestive loci in an independent sample series (samples from 1372 patients and 5094 controls) and then did joint phase and brain expression and methylation quantitative trait loci analyses for the associated (p −8 ) single-nucleotide polymorphisms. Findings We identified novel associations exceeding the genome-wide significance threshold (p −8 ). Combined (joint) analyses of discovery and replication phases showed genome-wide significant association at 6p21.3, HLA locus (immune system), for rs9268877 (p=1·05 × 10 −8 ; odds ratio=1·204 [95% CI 1·11–1·30]), rs9268856 (p=5·51 × 10 −9 ; 0·809 [0·76–0·86]) and rs1980493 (p value=1·57 × 10 −8 , 0·775 [0·69–0·86]) in the entire cohort. We also identified a potential novel locus at 11q14, encompassing RAB38 / CTSC (the transcripts of which are related to lysosomal biology), for the behavioural FTD subtype for which joint analyses showed suggestive association for rs302668 (p=2·44 × 10 −7 ; 0·814 [0·71–0·92]). Analysis of expression and methylation quantitative trait loci data suggested that these loci might affect expression and methylation in cis . Interpretation Our findings suggest that immune system processes (link to 6p21.3) and possibly lysosomal and autophagy pathways (link to 11q14) are potentially involved in FTD. Our findings need to be replicated to better define the association of the newly identified loci with disease and to shed light on the pathomechanisms contributing to FTD. Funding The National Institute of Neurological Disorders and Stroke and National Institute on Aging, the Wellcome/MRC Centre on Parkinson's disease, Alzheimer's Research UK, and Texas Tech University Health Sciences Center.

ObjectivesThis study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far.BackgroundSQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained.MethodsSeventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months).ResultsCardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range

Importance Diabetes is associated with an elevated risk of coronary heart disease (CHD). Previous studies have suggested that the genetic factors predisposing to excess cardiovascular risk may be different in diabetic and nondiabetic individuals. Objective To identify genetic determinants of CHD that are specific to patients with diabetes. Design, Setting, and Participants We studied 5 independent sets of CHD cases and CHD-negative controls from the Nurses’ Health Study (enrolled in 1976 and followed up through 2008), Health Professionals Follow-up Study (enrolled in 1986 and followed up through 2008), Joslin Heart Study (enrolled in 2001-2008), Gargano Heart Study (enrolled in 2001-2008), and Catanzaro Study (enrolled in 2004-2010). Included were a total of 1517 CHD cases and 2671 CHD-negative controls, all with type 2 diabetes. Results in diabetic patients were compared with those in 737 nondiabetic CHD cases and 1637 nondiabetic CHD-negative controls from the Nurses’ Health Study and Health Professionals Follow-up Study cohorts. Exposures included 2 543 016 common genetic variants occurring throughout the genome. Main Outcomes and Measures Coronary heart disease—defined as fatal or nonfatal myocardial infarction, coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, or angiographic evidence of significant stenosis of the coronary arteries. Results A variant on chromosome 1q25 (rs10911021) was consistently associated with CHD risk among diabetic participants, with risk allele frequencies of 0.733 in cases vs 0.679 in controls (odds ratio, 1.36 [95% CI, 1.22-1.51]; P = 2 × 10 −8 ). No association between this variant and CHD was detected among nondiabetic participants, with risk allele frequencies of 0.697 in cases vs 0.696 in controls (odds ratio, 0.99 [95% CI, 0.87-1.13]; P = .89), consistent with a significant gene × diabetes interaction on CHD risk ( P = 2 × 10 −4 ). Compared with protective allele homozygotes, rs10911021 risk allele homozygotes were characterized by a 32% decrease in the expression of the neighboring glutamate-ammonia ligase ( GLUL ) gene in human endothelial cells ( P = .0048). A decreased ratio between plasma levels of γ-glutamyl cycle intermediates pyroglutamic and glutamic acid was also shown in risk allele homozygotes ( P = .029). Conclusion and Relevance A single-nucleotide polymorphism (rs10911021) was identified that was significantly associated with CHD among persons with diabetes but not in those without diabetes and was functionally related to glutamic acid metabolism, suggesting a mechanistic link.

Long-living individuals (LLIs) are used to study exceptional longevity. A number of genetic variants have been found associated in LLIs to date, but further identification of variants would improve knowledge on the mechanisms regulating the rate of aging. Therefore, we performed a genome-wide association study on 410 LLIs and 553 young control individuals with a 317K single-nucleotide polymorphism (SNP) chip to identify novel traits associated with aging. Among the top (p

A number of potential candidate genes in a variety of biological pathways have been associated with longevity in model organisms. Many of these genes have human homologs and thus have the potential to provide insights into human longevity. Recently, several studies suggested that FOXO3A functions as a key bridge for various signaling pathways that influence aging and longevity. Interestingly, Willcox and colleagues identified several variants that displayed significant genotype-gender interaction in male human longevity. In particular, a nested case-control study was performed in an ethnic Japanese population in Hawaii, and five candidate longevity genes were chosen based on links to the insulin-insulin-like growth factor-1 (IGF-1) signaling pathway. In the Willcox study, the investigated genetic variations (rs2802292, rs2764264, and rs13217795) within the FOXO3A gene were significantly associated with longevity in male centenarians. We validated the association of FOXO3A polymorphisms with extreme longevity in males from the Southern Italian Centenarian Study. Particularly, rs2802288, a proxy of rs2802292, showed the best allelic association-minor allele frequency (MAF) = 0.49; p = 0.003; odds ratio (OR) = 1.51; 95% confidence interval (CI), 1.15-1.98). Furthermore, we undertook a meta-analysis to explore the significance of rs2802292 association with longevity by combining the association results of the current study and the findings coming from the Willcox et al. investigation. Our data point to a key role of FOXO3A in human longevity and confirm the feasibility of the identification of such genes with centenarian-controls studies. Moreover, we hypothesize the susceptibility to the longevity phenotype may well be the result of complex interactions involving genes and environmental factors but also gender. © Mary Ann Liebert, Inc.

Several epidemiological published data support the protective role of omega-3 consumption in coronary artery disease, sudden cardiac death and ventricular arrhythmias, but interestingly, this is not the case for atrial arrhythmias. The purpose of this study is to evaluate different fatty acid profile between AF/AFL subjects and healthy controls.Gas chromatography was employed to determine fatty acid percentage of erythrocyte membranes from 40 idiopathic AFL/AF patients and 53 healthy control subjects.AFL/AF erythrocyte membranes had significantly lower percentage of saturated fatty acid (43.1 +/- SD2.2 versus 47.8 +/- SD9.6, p0.001), monounsaturated fatty acid (18.2 +/- SD2.5 versus 22.6 +/- SD5.2, p0.001) and total trans fatty acid (0.2 +/- SD0.1 vs 1.3 +/- SD1.1, p0.001) than controls. Furthermore, fatty acid (FA) profiles of arrhythmic individuals showed an increased percent of total polyunsaturated fatty acid (PUFA) (36.7 +/- SD2.4 versus 26.4 +/- SD10.4, p0.001), PUFA n-3 (5.3 +/- SD1.1 versus 2.8 +/- SD1.8, p0.001) and n-6 (31.4 +/- SD2.2 versus 23.5 +/- SD9.9, p0.001).This study shows that the erythrocyte membranes FA composition of AF/AFL subjects differs from that of healthy controls.

Background: Atrial fibrillation (AF) and atrial flutter (AFL) are common cardiac conduction disorders affecting many people. Recent studies on sporadic cases of AF/AFL showed a significant association of the single nucleotide polymorphism rs2200733T with the disease, suggesting a genetic factor in the development of the disease. Objectives: To determine the association of rs2200733 with AF/AFL derived from an Italian population sample. Subjects: 78 patients with AF/AFL and 348 controls took part in the study. Design: Genetic case–control study. Results: The results indicate that there is a positive, significant association between the rs2200733 T allele and patients with AF/AFL of Italian origin (allelic p,0.001 with OR = 2.17). Conclusion: These results derived from a sample of the Italian population agree with previously reported findings from an Icelandic study, which also found that the minor allele rs2200733 was associated with AF/AFL disease. Cardiac conduction disorders may depend upon a variety of predisposing factors, including developmental and congenital defects, acquired injuries or ischaemia of the conduction system and rarely inherited genetic defects that alter the electrophysiological properties of the heart. Atrial fibrillation (AF) is the most common sustained arrhythmia (supraventricular tachyarrhythmia). 1 It is associated with increased cardiovascular morbidity and mortality and it is a leading cause of stroke. 2 Other predisposing disease states include diabetes mellitus, essential hypertension (EH), congestive heart failure, valvular disease and myocardial infarction. The electrophysiological mechanism underlying AF may include the following events: myocardial electrical conduction and structural remodelling, genetic changes, ectopic electrical activity within the pulmonary veins and oxidative stress of the cardiac tissue. 13 Thus, more than one mechanism may be involved in the onset of AF. AF and atrial flutter (AFL) are closely related. 4

The exceptional longevity of centenarians is due in part to inherited genetic factors, as deduced from data that show that first degree relatives of centenarians live longer and have reduced overall mortality. In recent years, a number of groups have performed genetic association studies on long-living individuals (LLI) and young controls to identify alleles that are either positively or negatively selected in the centenarian population as consequence of a demographic pressure. Many of the reported studies have shown genetic loci associated with longevity. Of these, with the exception of APOE, none have been convincingly reproduced. We validated our populations by typing the APOE locus. In addition, we used 749 American Caucasian LLI, organized in two independent tiers and 355 American Caucasian controls in the attempt to replicate previously published findings. We tested Klotho (KL)-VS variant (rs952706), Cholesteryl Ester Transfer Protein (CETP) I405V (rs5882), Paraoxonase 1 (PON1) Q192R (rs662), Apolipoprotein C-III (APOC3) -641C/A (rs2542052), Microsomal Transfer Protein (MTP) -493G/T (rs2866164) and apolipoprotein E (APOE) epsilon2 and epsilon4 isoforms, (rs7412 and rs429358) haplotypes respectively. Our results show that, at present, except for APOE, none of the selected genes show association with longevity if carefully tested in a large cohort of LLI and their controls, pointing to the need of larger populations for case-control studies in extreme longevity.

Offspring of long-lived individuals are a useful model to discover biomarkers of longevity. The lipid composition of erythrocyte membranes from 41 nonagenarian offspring was compared with 30 matched controls. Genetic loci were also tested in 280 centenarians and 280 controls to verify a potential genetic predisposition in determining unique lipid profile. Gas chromatography was employed to determine fatty acid composition, and genotyping was performed using Taqman assays. Outcomes were measured for erythrocyte membrane percentage content of saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids (omega-6 and omega-3), geometrical isomers of arachidonic and oleic acids, and total trans-fatty acids. Also, allele and genotyping frequencies at endothelial-nitric oxide synthase and delta-5/delta-6 and delta-9 desaturase loci were considered. Erythrocyte membranes from nonagenarian offspring had significantly higher content of C16:1 n-7, trans C18:1 n-9, and total trans-fatty acids, and reduced content of C18:2 n-6 and C20:4 n-6. No association was detected at endothelial-nitric oxide synthase and delta-5/delta-6 and delta-9 desaturase loci that could justify genetic predisposition for the increased trans C18:1 n-9, monounsaturated fatty acids and decreased omega-6 synthesis. We concluded that erythrocyte membranes derived from nonagenarian offspring have a different lipid composition (reduced lipid peroxidation and increased membrane integrity) to that of the general population.

Background Brugada syndrome (BrS) is associated with loss of sodium channel function. Previous studies showed features consistent with sodium current (I Na ) deficit in patients carrying desmosomal mutations, diagnosed with arrhythmogenic cardiomyopathy ([AC]; or arrhythmogenic right ventricular cardiomyopathy [ARVC]). Experimental models showed correlation between loss of expression of desmosomal protein plakophilin-2 (PKP2) and reduced I Na . We hypothesized that PKP2 variants that reduce I Na could yield a BrS phenotype, even without cardiomyopathic features of AC. Methods and Results We searched for PKP2 variants in genomic DNA of 200 patients with BrS diagnosis, no signs of AC, and no mutations in BrS-related genes SCN5A, CACNa1c, GPD1L, and MOG1 . We identified 5 cases of single amino acid substitutions. One (Q62K) was previously described in AC patients as a variant of unknown significance; 4 were unreported. In a family with multiple cases of syncope and/or suspect ECG, novel variant R635Q cosegregated with the phenotype in all affected relatives and was absent in the nonaffected ones. Mutations were tested in HL-1–derived cells endogenously expressing Na v 1.5 but made deficient in PKP2 (PKP2-KD). Loss of PKP2 caused decreased I Na and Na v 1.5 at site of cell contact. These deficits were restored by transfection of wild-type PKP2 (PKP2-WT) but not of BrS-related PKP2 mutants. Similar results were obtained when cells were cotransfected with PKP2-WT and the BrS-related PKP2 variants, to mimic heterozygosity. Human-induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) from a patient with PKP2 deficit showed drastically reduced I Na . The deficit was restored by transfection of WT but not BrS-related PKP2 variant R635Q. Superresolution microscopy in murine PKP2-deficient cardiomyocytes related I Na deficiency to reduced number of channels at the intercalated disk and increased separation of microtubules from the cell end. Conclusions This is the first systematic retrospective analysis of a patient group to define the coexistence of sodium channelopathy and genetic PKP2 variations. PKP2 mutations may be a molecular substrate leading to the diagnosis of BrS.