Publications by authors named "Eline A Nannenberg"

19 Publications

  • Page 1 of 1

Mutation Type and a Genetic Risk Score Associate Variably With Brugada Syndrome Phenotype in Families.

Circ Genom Precis Med 2020 12 9;13(6):e002911. Epub 2020 Nov 9.

Molecular and Clinical Sciences Research Institute, St George's University of London, Cardiovascular Clinical Academic Group, St George's University Hospitals National Health Service (NHS) Foundation Trust, United Kingdom (Y.D.W., V.B., M.M., H.R., M.P., S.S., E.R.B.).

Background: Brugada syndrome (BrS) is characterized by the type 1 Brugada ECG pattern. Pathogenic rare variants in (mutations) are identified in 20% of BrS families in whom incomplete penetrance and genotype-negative phenotype-positive individuals are observed. E1784K- is the most common mutation identified. We determined the association of a BrS genetic risk score (BrS-GRS) and mutation type on BrS phenotype in BrS families with mutations.

Methods: Subjects with a spontaneous type 1 pattern or positive/negative drug challenge from cohorts harboring mutations were recruited from 16 centers (n=312). Single nucleotide polymorphisms previously associated with BrS at genome-wide significance were studied in both cohorts: rs11708996, rs10428132, and rs9388451. An additive linear genetic model for the BrS-GRS was assumed (6 single nucleotide polymorphism risk alleles).

Results: In the total population (n=312), BrS-GRS ≥4 risk alleles yielded an odds ratio of 4.15 for BrS phenotype ([95% CI, 1.45-11.85]; =0.0078). Among -positive individuals (n=258), BrS-GRS ≥4 risk alleles yielded an odds ratio of 2.35 ([95% CI, 0.89-6.22]; =0.0846). In -negative relatives (n=54), BrS-GRS ≥4 alleles yielded an odds ratio of 22.29 ([95% CI, 1.84-269.30]; =0.0146). Among E1784K- positive family members (n=79), hosting ≥4 risk alleles gave an odds ratio=5.12 ([95% CI, 1.93-13.62]; =0.0011).

Conclusions: Common genetic variation is associated with variable expressivity of BrS phenotype in families, explaining in part incomplete penetrance and genotype-negative phenotype-positive individuals. mutation genotype and a BrS-GRS associate with BrS phenotype, but the strength of association varies according to presence of a mutation and severity of loss of function.
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http://dx.doi.org/10.1161/CIRCGEN.120.002911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7748043PMC
December 2020

Enhancing rare variant interpretation in inherited arrhythmias through quantitative analysis of consortium disease cohorts and population controls.

Authors:
Roddy Walsh Najim Lahrouchi Rafik Tadros Florence Kyndt Charlotte Glinge Pieter G Postema Ahmad S Amin Eline A Nannenberg James S Ware Nicola Whiffin Francesco Mazzarotto Doris Škorić-Milosavljević Christian Krijger Elena Arbelo Dominique Babuty Hector Barajas-Martinez Britt M Beckmann Stéphane Bézieau J Martijn Bos Jeroen Breckpot Oscar Campuzano Silvia Castelletti Candan Celen Sebastian Clauss Anniek Corveleyn Lia Crotti Federica Dagradi Carlo de Asmundis Isabelle Denjoy Sven Dittmann Patrick T Ellinor Cristina Gil Ortuño Carla Giustetto Jean-Baptiste Gourraud Daisuke Hazeki Minoru Horie Taisuke Ishikawa Hideki Itoh Yoshiaki Kaneko Jørgen K Kanters Hiroki Kimoto Maria-Christina Kotta Ingrid P C Krapels Masahiko Kurabayashi Julieta Lazarte Antoine Leenhardt Bart L Loeys Catarina Lundin Takeru Makiyama Jacques Mansourati Raphaël P Martins Andrea Mazzanti Stellan Mörner Carlo Napolitano Kimie Ohkubo Michael Papadakis Boris Rudic Maria Sabater Molina Frédéric Sacher Hatice Sahin Georgia Sarquella-Brugada Regina Sebastiano Sanjay Sharma Mary N Sheppard Keiko Shimamoto M Benjamin Shoemaker Birgit Stallmeyer Johannes Steinfurt Yuji Tanaka David J Tester Keisuke Usuda Paul A van der Zwaag Sonia Van Dooren Lut Van Laer Annika Winbo Bo G Winkel Kenichiro Yamagata Sven Zumhagen Paul G A Volders Steven A Lubitz Charles Antzelevitch Pyotr G Platonov Katja E Odening Dan M Roden Jason D Roberts Jonathan R Skinner Jacob Tfelt-Hansen Maarten P van den Berg Morten S Olesen Pier D Lambiase Martin Borggrefe Kenshi Hayashi Annika Rydberg Tadashi Nakajima Masao Yoshinaga Johan B Saenen Stefan Kääb Pedro Brugada Tomas Robyns Daniela F Giachino Michael J Ackerman Ramon Brugada Josep Brugada Juan R Gimeno Can Hasdemir Pascale Guicheney Silvia G Priori Eric Schulze-Bahr Naomasa Makita Peter J Schwartz Wataru Shimizu Takeshi Aiba Jean-Jacques Schott Richard Redon Seiko Ohno Vincent Probst Elijah R Behr Julien Barc Connie R Bezzina

Genet Med 2021 Jan 7;23(1):47-58. Epub 2020 Sep 7.

Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.

Purpose: Stringent variant interpretation guidelines can lead to high rates of variants of uncertain significance (VUS) for genetically heterogeneous disease like long QT syndrome (LQTS) and Brugada syndrome (BrS). Quantitative and disease-specific customization of American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines can address this false negative rate.

Methods: We compared rare variant frequencies from 1847 LQTS (KCNQ1/KCNH2/SCN5A) and 3335 BrS (SCN5A) cases from the International LQTS/BrS Genetics Consortia to population-specific gnomAD data and developed disease-specific criteria for ACMG/AMP evidence classes-rarity (PM2/BS1 rules) and case enrichment of individual (PS4) and domain-specific (PM1) variants.

Results: Rare SCN5A variant prevalence differed between European (20.8%) and Japanese (8.9%) BrS patients (p = 5.7 × 10) and diagnosis with spontaneous (28.7%) versus induced (15.8%) Brugada type 1 electrocardiogram (ECG) (p = 1.3 × 10). Ion channel transmembrane regions and specific N-terminus (KCNH2) and C-terminus (KCNQ1/KCNH2) domains were characterized by high enrichment of case variants and >95% probability of pathogenicity. Applying the customized rules, 17.4% of European BrS and 74.8% of European LQTS cases had (likely) pathogenic variants, compared with estimated diagnostic yields (case excess over gnomAD) of 19.2%/82.1%, reducing VUS prevalence to close to background rare variant frequency.

Conclusion: Large case-control data sets enable quantitative implementation of ACMG/AMP guidelines and increased sensitivity for inherited arrhythmia genetic testing.
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http://dx.doi.org/10.1038/s41436-020-00946-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7790744PMC
January 2021

Transethnic Genome-Wide Association Study Provides Insights in the Genetic Architecture and Heritability of Long QT Syndrome.

Authors:
Najim Lahrouchi Rafik Tadros Lia Crotti Yuka Mizusawa Pieter G Postema Leander Beekman Roddy Walsh Kanae Hasegawa Julien Barc Marko Ernsting Kari L Turkowski Andrea Mazzanti Britt M Beckmann Keiko Shimamoto Ulla-Britt Diamant Yanushi D Wijeyeratne Yu Kucho Tomas Robyns Taisuke Ishikawa Elena Arbelo Michael Christiansen Annika Winbo Reza Jabbari Steven A Lubitz Johannes Steinfurt Boris Rudic Bart Loeys M Ben Shoemaker Peter E Weeke Ryan Pfeiffer Brianna Davies Antoine Andorin Nynke Hofman Federica Dagradi Matteo Pedrazzini David J Tester J Martijn Bos Georgia Sarquella-Brugada Óscar Campuzano Pyotr G Platonov Birgit Stallmeyer Sven Zumhagen Eline A Nannenberg Jan H Veldink Leonard H van den Berg Ammar Al-Chalabi Christopher E Shaw Pamela J Shaw Karen E Morrison Peter M Andersen Martina Müller-Nurasyid Daniele Cusi Cristina Barlassina Pilar Galan Mark Lathrop Markus Munter Thomas Werge Marta Ribasés Tin Aung Chiea C Khor Mineo Ozaki Peter Lichtner Thomas Meitinger J Peter van Tintelen Yvonne Hoedemaekers Isabelle Denjoy Antoine Leenhardt Carlo Napolitano Wataru Shimizu Jean-Jacques Schott Jean-Baptiste Gourraud Takeru Makiyama Seiko Ohno Hideki Itoh Andrew D Krahn Charles Antzelevitch Dan M Roden Johan Saenen Martin Borggrefe Katja E Odening Patrick T Ellinor Jacob Tfelt-Hansen Jonathan R Skinner Maarten P van den Berg Morten Salling Olesen Josep Brugada Ramón Brugada Naomasa Makita Jeroen Breckpot Masao Yoshinaga Elijah R Behr Annika Rydberg Takeshi Aiba Stefan Kääb Silvia G Priori Pascale Guicheney Hanno L Tan Christopher Newton-Cheh Michael J Ackerman Peter J Schwartz Eric Schulze-Bahr Vincent Probst Minoru Horie Arthur A Wilde Michael W T Tanck Connie R Bezzina

Circulation 2020 Jul 20;142(4):324-338. Epub 2020 May 20.

Amsterdam UMC, University of Amsterdam, Heart Center; Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, The Netherlands (N.L., R.T., Y.M., P.G.P., L.B., R.W., N.H., H.L.T., A.A.W., C.R.B.).

Background: Long QT syndrome (LQTS) is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. A causal rare genetic variant with large effect size is identified in up to 80% of probands (genotype positive) and cascade family screening shows incomplete penetrance of genetic variants. Furthermore, a proportion of cases meeting diagnostic criteria for LQTS remain genetically elusive despite genetic testing of established genes (genotype negative). These observations raise the possibility that common genetic variants with small effect size contribute to the clinical picture of LQTS. This study aimed to characterize and quantify the contribution of common genetic variation to LQTS disease susceptibility.

Methods: We conducted genome-wide association studies followed by transethnic meta-analysis in 1656 unrelated patients with LQTS of European or Japanese ancestry and 9890 controls to identify susceptibility single nucleotide polymorphisms. We estimated the common variant heritability of LQTS and tested the genetic correlation between LQTS susceptibility and other cardiac traits. Furthermore, we tested the aggregate effect of the 68 single nucleotide polymorphisms previously associated with the QT-interval in the general population using a polygenic risk score.

Results: Genome-wide association analysis identified 3 loci associated with LQTS at genome-wide statistical significance (<5×10) near , , and , and 1 missense variant in (p.Asp85Asn) at the suggestive threshold (<10). Heritability analyses showed that ≈15% of variance in overall LQTS susceptibility was attributable to common genetic variation ( 0.148; standard error 0.019). LQTS susceptibility showed a strong genome-wide genetic correlation with the QT-interval in the general population (r=0.40; =3.2×10). The polygenic risk score comprising common variants previously associated with the QT-interval in the general population was greater in LQTS cases compared with controls (<10-13), and it is notable that, among patients with LQTS, this polygenic risk score was greater in patients who were genotype negative compared with those who were genotype positive (<0.005).

Conclusions: This work establishes an important role for common genetic variation in susceptibility to LQTS. We demonstrate overlap between genetic control of the QT-interval in the general population and genetic factors contributing to LQTS susceptibility. Using polygenic risk score analyses aggregating common genetic variants that modulate the QT-interval in the general population, we provide evidence for a polygenic architecture in genotype negative LQTS.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.045956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382531PMC
July 2020

An International, Multicentered, Evidence-Based Reappraisal of Genes Reported to Cause Congenital Long QT Syndrome.

Circulation 2020 02 27;141(6):418-428. Epub 2020 Jan 27.

Division of Cardiology, Toronto General Hospital and University of Toronto, Canada (A.A, M.C., M.H.G.).

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 () were classified as having limited or disputed evidence as LQTS-causative genes. Only 3 genes () were curated as definitive genes for typical LQTS. Another 4 genes () were found to have strong or definitive evidence for causality in LQTS with atypical features, including neonatal atrioventricular block. The remaining gene () 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.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.119.043132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7017940PMC
February 2020

Pregnancy in Catecholaminergic Polymorphic Ventricular Tachycardia.

JACC Clin Electrophysiol 2019 03 26;5(3):387-394. Epub 2018 Dec 26.

Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

Objectives: This investigation was a retrospective study of catecholaminergic polymorphic ventricular tachycardia (CPVT) patients in Canada and the Netherlands to compare pregnancy, postpartum, and nonpregnant event rates.

Background: CPVT is characterized by life-threatening arrhythmias during exertion or emotional stress. The arrhythmic risk in CPVT patients during pregnancy is unknown.

Methods: Baseline demographics, genetics, treatment, and pregnancy complications were reviewed. Event rate calculations assumed a 40-week pregnancy and 24-week postpartum period.

Results: Ninety-six CPVT patients had 228 pregnancies (median 2 pregnancies per patient; range: 1 to 10; total: 175.4 pregnant patient-years). The median age of CPVT diagnosis was 40.7 years (range: 12 to 84 years), with a median follow-up of 2.9 years (range: 0 to 20 years; total 448.1 patient-years). Most patients had pregnancies before CPVT diagnosis (82%). Pregnancy and postpartum cardiac events included syncope (5%) and an aborted cardiac arrest (1%), which occurred in patients who were not taking beta-blockers. Other complications included miscarriages (13%) and intrauterine growth restriction (1 case). There were 6 cardiac events (6%) during the nonpregnant period. The pregnancy and postpartum event rates were 1.71 and 2.85 events per 100 patient-years, respectively, and the combined event rate during the pregnancy and postpartum period was 2.14 events per 100 patient-years. These rates were not different from the nonpregnant event rate (1.46 events per 100 patient-years).

Conclusions: The combined pregnancy and postpartum arrhythmic risk in CPVT patients was not elevated compared with the nonpregnant period. Most patients had pregnancies before diagnosis, and all patients with events were not taking beta-blockers at the time of the event.
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http://dx.doi.org/10.1016/j.jacep.2018.10.019DOI Listing
March 2019

Effect of Ascertainment Bias on Estimates of Patient Mortality in Inherited Cardiac Diseases.

Circ Genom Precis Med 2018 10;11(10):e001797

Department of Clinical Genetics (E.A.N., J.P.v.T., I.C.), Academic Medical Center, Amsterdam, The Netherlands.

Background: Accurate estimates of survival are indispensable for cardiologists, clinical geneticists, and genetic counselors dealing with families with an inherited cardiac disease. However, a bias towards a more severe disease with a worse outcome in the first publications may not accurately represent the actual survival forecast. We, therefore, evaluated the effect of ascertainment bias on survival in 3 different inherited cardiac diseases (idiopathic ventricular fibrillation, SCN5A overlap syndrome, and arrhythmogenic cardiomyopathy) caused by a founder mutation.

Methods: We collected mortality data from mutation-positive subjects with either DPP6-associated idiopathic ventricular fibrillation, SCN5A overlap syndrome, and PLN-R14del-mediated arrhythmogenic cardiomyopathy >2 to 10 years of ongoing clinical/cascade genetic screening.

Results: The median age of survival in DPP6 mutation-positive subjects increased from 44.6 years in the original cohort from 2008 (n=60; 95% CI, 36.8-52.4 years) to 68.2 years in the extended cohort from 2012 (n=235; 95% CI, 64.6-71.7 years; P<0.001). In the SCN5A overlap syndrome, survival increased from 56.1 years in 1999 (n=86; 95% CI, 48.0-64.2 years) to 69.7 years in 2009 (n=197; 95% CI, 61.3-78.2 years; P=0.049). In PLN-R14del positive patients, the median age of survival increased from 63.5 years in 2010 (n=89; 95% CI, 59.1-68.0 years) to 65.2 years in 2012 (n=370; 95% CI, 62.0-68.3 years; P=0.046).

Conclusions: The median age of survival in 3 different inherited cardiac diseases with an established pathogenic substrate significantly increased once genetic testing and cascade screening extended, after the first publication that elucidated the discovery of the disease-susceptibility gene/mutation. This underscores the direct and negative influence of ascertainment bias on survival forecasts and the importance of ongoing clinical/genetic follow-up to establish the most accurate disease prognosis for genetically mediated heart diseases.
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http://dx.doi.org/10.1161/CIRCGEN.117.001797DOI Listing
October 2018

Yield and Pitfalls of Ajmaline Testing in the Evaluation of Unexplained Cardiac Arrest and Sudden Unexplained Death: Single-Center Experience With 482 Families.

JACC Clin Electrophysiol 2017 12 28;3(12):1400-1408. Epub 2017 Jun 28.

Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, the Netherlands. Electronic address:

Objectives: This study evaluated the yield of ajmaline testing and assessed the occurrence of confounding responses in a large cohort of families with unexplained cardiac arrest (UCA) or sudden unexplained death (SUD).

Background: Ajmaline testing to diagnose Brugada syndrome (BrS) is routinely used in the evaluation of SUD and UCA, but its yield, limitations, and appropriate dosing have not been studied in a large cohort.

Methods: We assessed ajmaline test response and genetic testing results in 637 individuals from 482 families who underwent ajmaline testing for SUD or UCA.

Results: Overall, 89 individuals (14%) from 88 families (18%) had a positive ajmaline test result. SCN5A mutations were identified in 9 of 86 ajmaline-positive cases (10%). SCN5A mutation carriers had positive test results at significantly lower ajmaline doses than noncarriers (0.75 [range: 0.64 to 0.98] mg/kg vs. 1.03 [range: 0.95 to 1.14] mg/kg, respectively; p < 0.01). In 7 of 88 families (8%), it was concluded that the positive ajmaline response was a confounder, either in the presence of an alternative genetic diagnosis accounting for UCA/SUD (5 cases) or noncosegregation of positive ajmaline response and arrhythmia (2 cases). The rate of confounding responses was significantly higher in positive ajmaline responses obtained at >1 mg/kg than in those obtained at ≤1 mg/kg (7 of 48 vs. 0 of 41 individuals; Fisher's exact test: p = 0.014).

Conclusions: In line with previous, smaller studies, a positive ajmaline response was observed in a large proportion of UCA/SUD families. Importantly, our data emphasize the potential for confounding possibly false-positive ajmaline responses in this population, particularly at high doses, which could possibly lead to a misdiagnosis. Clinicians should consider all alternative causes in UCA/SUD and avoid ajmaline doses >1 mg/kg.
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http://dx.doi.org/10.1016/j.jacep.2017.04.005DOI Listing
December 2017

A common co-morbidity modulates disease expression and treatment efficacy in inherited cardiac sodium channelopathy.

Eur Heart J 2018 08;39(31):2898-2907

Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, University of Amsterdam, Meibergdreef 15, PO Box 22660, 1100 DD Amsterdam, The Netherlands.

Aims: Management of patients with inherited cardiac ion channelopathy is hindered by variability in disease severity and sudden cardiac death (SCD) risk. Here, we investigated the modulatory role of hypertrophy on arrhythmia and SCD risk in sodium channelopathy.

Methods And Results: Follow-up data was collected from 164 individuals positive for the SCN5A-1795insD founder mutation and 247 mutation-negative relatives. A total of 38 (obligate) mutation-positive patients died suddenly or suffered life-threatening ventricular arrhythmia. Of these, 18 were aged >40 years, a high proportion of which had a clinical diagnosis of hypertension and/or cardiac hypertrophy. While pacemaker implantation was highly protective in preventing bradycardia-related SCD in young mutation-positive patients, seven of them aged >40 experienced life-threatening arrhythmic events despite pacemaker treatment. Of these, six had a diagnosis of hypertension/hypertrophy, pointing to a modulatory role of this co-morbidity. Induction of hypertrophy in adult mice carrying the homologous mutation (Scn5a1798insD/+) caused SCD and excessive conduction disturbances, confirming a modulatory effect of hypertrophy in the setting of the mutation. The deleterious effects of the interaction between hypertrophy and the mutation were prevented by genetically impairing the pro-hypertrophic response and by pharmacological inhibition of the enhanced late sodium current associated with the mutation.

Conclusion: This study provides the first evidence for a modulatory effect of co-existing cardiac hypertrophy on arrhythmia risk and treatment efficacy in inherited sodium channelopathy. Our findings emphasize the need for continued assessment and rigorous treatment of this co-morbidity in SCN5A mutation-positive individuals.
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http://dx.doi.org/10.1093/eurheartj/ehy247DOI Listing
August 2018

GNB5 Mutations Cause an Autosomal-Recessive Multisystem Syndrome with Sinus Bradycardia and Cognitive Disability.

Am J Hum Genet 2016 09 11;99(3):704-710. Epub 2016 Aug 11.

Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, viale Cappuccini, 71013 San Giovanni Rotondo, Foggia, Italy. Electronic address:

GNB5 encodes the G protein β subunit 5 and is involved in inhibitory G protein signaling. Here, we report mutations in GNB5 that are associated with heart-rate disturbance, eye disease, intellectual disability, gastric problems, hypotonia, and seizures in nine individuals from six families. We observed an association between the nature of the variants and clinical severity; individuals with loss-of-function alleles had more severe symptoms, including substantial developmental delay, speech defects, severe hypotonia, pathological gastro-esophageal reflux, retinal disease, and sinus-node dysfunction, whereas related heterozygotes harboring missense variants presented with a clinically milder phenotype. Zebrafish gnb5 knockouts recapitulated the phenotypic spectrum of affected individuals, including cardiac, neurological, and ophthalmological abnormalities, supporting a direct role of GNB5 in the control of heart rate, hypotonia, and vision.
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http://dx.doi.org/10.1016/j.ajhg.2016.06.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5010642PMC
September 2016

Type 1 papillary renal cell carcinoma in a patient with schwannomatosis: Mosaic versus loss of SMARCB1 expression in respectively schwannoma and renal tumor cells.

Genes Chromosomes Cancer 2016 Apr 22;55(4):350-4. Epub 2016 Jan 22.

Department of Pathology, Nijmegen Center for Molecular Life Sciences (NCMLS), Radboud University Medical Center, Nijmegen, The Netherlands.

In schwannomatosis, germline SMARCB1 or LZTR1 mutations predispose to the development of multiple benign schwannomas. Besides these, other tumors may occur in schwannomatosis patients. We present a 45-year-old male patient who developed multiple schwannomas and in addition a malignant type 1 papillary renal cell carcinoma (pRCC1). We identified a duplication of exon 7 of SMARCB1 on chromosome 22 in the constitutional DNA of the patient (c.796-2246_986 + 5250dup7686), resulting in the generation of a premature stop codon in the second exon 7 copy (p.Glu330*). The mutant SMARCB1 allele proved to be retained in three schwannomas and in the pRCC1 of the patient. Loss of heterozygosity analysis demonstrated partial loss of the wild-type SMARCB1 allele containing chromosome 22, suggesting loss of that chromosome in only a subset of tumor cells, in all four tumors. Immunohistochemical staining with a SMARCB1 antibody revealed a mosaic SMARCB1 expression pattern in the three benign schwannomas, but absence of expression in the malignant tumor cells of the pRCC1. To our knowledge, this difference in SMARCB1 protein expression has not been reported before. We conclude that a germline SMARCB1 mutation may predispose to the development of pRCC1, thereby further widening the spectrum of tumors that can develop in the context of schwannomatosis.
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http://dx.doi.org/10.1002/gcc.22338DOI Listing
April 2016

Detailed characterization of familial idiopathic ventricular fibrillation linked to the DPP6 locus.

Heart Rhythm 2016 Apr 8;13(4):905-12. Epub 2015 Dec 8.

Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia. Electronic address:

Background: Familial idiopathic ventricular fibrillation (IVF) is a severe disease entity and is notoriously difficult to manage because there are no clinical risk indicators for premature cardiac arrest. Previously, we identified a link between familial IVF and a risk haplotype on chromosome 7q36 (involving the arrhythmia gene DPP6).

Objective: The purpose of this study was to expand our knowledge of familial IVF and to discuss its (extended) clinical characteristics.

Methods: We studied 601 family members and probands: 286 DPP6 risk-haplotype positive (haplotype-positive) and 315 DPP6 risk-haplotype negative (haplotype-negative) individuals. Clinical parameters, a combination of all-cause mortality and (aborted) cardiac arrest and differences between haplotype-positives and haplotype-negatives, were evaluated.

Results: There were no differences in electrocardiographic indices between haplotype-positives and haplotype-negatives, or between haplotype-positives with or without events. Cardiac magnetic resonance documented slightly larger ventricular volumes in haplotype-positives compared to controls (P <.05), but these were not clinically useful. Mortality and/or cardiac arrest occurred in 85 haplotype-positives (30%) and 18 haplotype-negatives (6%). Twenty-four haplotype-positives (8% male) were resuscitated from ventricular fibrillation (VF). Documented VF was always elicited by monomorphic short-coupled extrasystoles from the right ventricular apex/lower free wall. Median survival in risk-haplotype haplotype-positives was 70 vs. 93 years for haplotype-negatives (P < .01), with a worse phenotype in males (median survival 63 vs. 83 years in females, P < .01). Implantable cardioverter-defibrillators were implanted in 99 patients (76 [77%] for primary prevention). Two arrhythmic events occurred in the primary prevention group during follow-up (5 ± 3 years).

Conclusion: Despite our extensive analysis, the complexity in identifying asymptomatic IVF family members at risk for future arrhythmias based on clinical parameters is once more demonstrated.
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http://dx.doi.org/10.1016/j.hrthm.2015.12.006DOI Listing
April 2016

Role of common and rare variants in SCN10A: results from the Brugada syndrome QRS locus gene discovery collaborative study.

Cardiovasc Res 2015 Jun 17;106(3):520-9. Epub 2015 Feb 17.

Human Genetics Research Centre, ICCS, St George's University of London, London SW17 0RE, UK

Aims: Brugada syndrome (BrS) remains genetically heterogeneous and is associated with slowed cardiac conduction. We aimed to identify genetic variation in BrS cases at loci associated with QRS duration.

Methods And Results: A multi-centre study sequenced seven candidate genes (SCN10A, HAND1, PLN, CASQ2, TKT, TBX3, and TBX5) in 156 Caucasian SCN5A mutation-negative BrS patients (80% male; mean age 48) with symptoms (64%) and/or a family history of sudden death (47%) or BrS (18%). Forty-nine variants were identified: 18 were rare (MAF <1%) and non-synonymous; and 11/18 (61.1%), mostly in SCN10A, were predicted as pathogenic using multiple bioinformatics tools. Allele frequencies were compared with the Exome Sequencing and UK10K Projects. SKAT methods tested rare variation in SCN10A finding no statistically significant difference between cases and controls. Co-segregation analysis was possible for four of seven probands carrying a novel pathogenic variant. Only one pedigree (I671V/G1299A in SCN10A) showed co-segregation. The SCN10A SNP V1073 was, however, associated strongly with BrS [66.9 vs. 40.1% (UK10K) OR (95% CI) = 3.02 (2.35-3.87), P = 8.07 × 10-19]. Voltage-clamp experiments for NaV1.8 were performed for SCN10A common variants V1073, A1073, and rare variants of interest: A200V and I671V. V1073, A200V and I671V, demonstrated significant reductions in peak INa compared with ancestral allele A1073 (rs6795970).

Conclusion: Rare variants in the screened QRS-associated genes (including SCN10A) are not responsible for a significant proportion of SCN5A mutation negative BrS. The common SNP SCN10A V1073 was strongly associated with BrS and demonstrated loss of NaV1.8 function, as did rare variants in isolated patients.
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http://dx.doi.org/10.1093/cvr/cvv042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447806PMC
June 2015

Outcome in phospholamban R14del carriers: results of a large multicentre cohort study.

Circ Cardiovasc Genet 2014 Aug 8;7(4):455-65. Epub 2014 Jun 8.

Departments of Cardiology (I.A.W.v.R., Y.M.P., H.L.T., A.A.M.W.), Genetics (E.A.N., R.H.L.d.D., I.C.), and Epidemiology (A.H.Z.), Academic Medical Center, Amsterdam, The Netherlands; Departments of Genetics (P.A.v.d.Z., J.D.H.J., J.P.v.T.) and Cardiology (R.A.d.B., M.P.v.d.B.), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands (J.A.G., Y.M.P., R.N.W.H., A.A.M.W.); Departments of Cardiology (J.A.G., R.N.W.H.) and Genetics (J.G.P.), University Medical Center Utrecht, Utrecht, The Netherlands.

Background: The pathogenic phospholamban R14del mutation causes dilated and arrhythmogenic right ventricular cardiomyopathies and is associated with an increased risk of malignant ventricular arrhythmias and end-stage heart failure. We performed a multicentre study to evaluate mortality, cardiac disease outcome, and risk factors for malignant ventricular arrhythmias in a cohort of phospholamban R14del mutation carriers.

Methods And Results: Using the family tree mortality ratio method in a cohort of 403 phospholamban R14del mutation carriers, we found a standardized mortality ratio of 1.7 (95% confidence interval, 1.4-2.0) with significant excess mortality starting from the age of 25 years. Cardiological data were available for 295 carriers. In a median follow-up period of 42 months, 55 (19%) individuals had a first episode of malignant ventricular arrhythmias and 33 (11%) had an end-stage heart failure event. The youngest age at which a malignant ventricular arrhythmia occurred was 20 years, whereas for an end-stage heart failure event this was 31 years. Independent risk factors for malignant ventricular arrhythmias were left ventricular ejection fraction <45% and sustained or nonsustained ventricular tachycardia with hazard ratios of 4.0 (95% confidence interval, 1.9-8.1) and 2.6 (95% confidence interval, 1.5-4.5), respectively.

Conclusions: Phospholamban R14del mutation carriers are at high risk for malignant ventricular arrhythmias and end-stage heart failure, with left ventricular ejection fraction <45% and sustained or nonsustained ventricular tachycardia as independent risk factors. High mortality and a poor prognosis are present from late adolescence. Genetic and cardiac screening is, therefore, advised from adolescence onwards.
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http://dx.doi.org/10.1161/CIRCGENETICS.113.000374DOI Listing
August 2014

Gender-specific differences in major cardiac events and mortality in lamin A/C mutation carriers.

Eur J Heart Fail 2013 Apr 25;15(4):376-84. Epub 2012 Nov 25.

Department of Cardiology (Heart Failure Research Center), Academic Medical Center, Amsterdam, The Netherlands.

Aims: Mutations in the lamin A/C gene (LMNA) cause a variety of clinical phenotypes, including dilated cardiomyopathy. LMNA is one of the most prevalent mutated genes in dilated cardiomyopathy, and is associated with a high risk of arrhythmias, sudden cardiac death, and heart failure. There are few data on the impact of age and gender on cardiac disease penetrance and mortality.

Methods And Results: In a multicentre cohort of 269 LMNA mutation carriers, we evaluated gender-specific penetrance of cardiac involvement and major cardiac events. All-cause mortality of mutation carriers [standardized mortality ratio (SMR)] was determined. Cardiac disease penetrance was age dependent and almost complete at the age of 70 years. The presence of an LVEF ≤45% was significantly higher in men (P < 0.001). However, there was no difference between genders in the prevalence of atrioventricular block, atrial tachyarrhythmias, and non-sustained ventricular tachycardia. Malignant ventricular arrhythmias (26% vs. 8%) and end-stage heart failure (28% vs. 14%) were more common in men than in women (P < 0.001 and P = 0.006, respectively). All-cause mortality of mutation carriers was significantly increased [SMR 4.0, 95% confidence interval (CI) 2.8-5.2] between the ages of 15 and 75 years. Mortality in men was higher than in women (hazard ratio 2.2, 95% CI 1.2-4.3).

Conclusions: This large cohort of LMNA mutation carriers demonstrates a high cardiac disease penetrance and a high mortality in mutation carriers. Male mutation carriers have a worse prognosis due to a higher prevalence of malignant ventricular arrhythmias and end-stage heart failure.
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http://dx.doi.org/10.1093/eurjhf/hfs191DOI Listing
April 2013

Mortality of inherited arrhythmia syndromes: insight into their natural history.

Circ Cardiovasc Genet 2012 Apr 28;5(2):183-9. Epub 2012 Feb 28.

Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands.

Background: For most arrhythmia syndromes, the risk of sudden cardiac death for asymptomatic mutation carriers is ill defined. Data on the natural history of these diseases, therefore, are essential. The family tree mortality ratio method offers the unique possibility to study the natural history at a time when the disease was not known and patients received no treatment.

Methods And Results: In 6 inherited arrhythmia syndromes caused by specific mutations, we analyzed all-cause mortality with the family tree mortality ratio method (main outcome measure, standardized mortality ratio [SMR]). In long-QT syndrome (LQTS) type 1, severely increased mortality risk during all years of childhood was observed (1-19 years), in particular during the first 10 years of life (SMR, 2.9; 95% CI, 1.5-5.1). In LQTS type 2, we observed increasing SMRs starting from age 15 years, which just reached significance between age 30 and 39 (SMR, 4.0; 95% CI, 1.1-10.0). In LQTS type 3, the SMR was increased between age 15 and 19 years (SMR, 5.8; 95% CI, 1.2-16.9). In the SCN5A overlap syndrome, excess mortality was observed between age 10 and 59 years, with a peak between 20 and 39 years (SMR, 3.8; 95% CI, 2.5-5.7). In catecholaminergic polymorphic ventricular tachycardia, excess mortality was restricted to ages 20 to 39 years (SMR, 3.0; 95% CI, 1.3-6.0). In Brugada syndrome, excess mortality was observed between age 40 and 59 (SMR, 1.79; 95% CI, 1.2-2.4), particularly in men.

Conclusions: We identified age ranges during which the mortality risk manifests in an unselected and untreated population, which can guide screening in these families.
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http://dx.doi.org/10.1161/CIRCGENETICS.111.961102DOI Listing
April 2012

Mortality risk of untreated myosin-binding protein C-related hypertrophic cardiomyopathy: insight into the natural history.

J Am Coll Cardiol 2011 Nov;58(23):2406-14

Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands.

Objectives: The goal of this study was to assess the mortality of hypertrophic cardiomyopathy (HCM), partly in times when the disease was not elucidated and patients were untreated.

Background: HCM is feared for the risk of sudden cardiac death (SCD). Insight in the natural history of the disorder is needed to design proper screening strategies for families with HCM.

Methods: In 6 large, 200-year multigenerational pedigrees (identified by using genealogical searches) and in 140 small (contemporary) pedigrees (first-degree relatives of the proband) with HCM caused by a truncating mutation in the myosin-binding protein C gene (n = 1,118), we determined all-cause mortality using the family tree mortality ratio method. The study's main outcome measure was the standardized mortality ratio (SMR).

Results: In the large pedigrees, overall mortality was not increased (SMR 0.86 [95% confidence interval (CI): 0.72 to 1.03]), but significant excess mortality occurred between 10 and 19 years (SMR 2.7 [95% CI: 1.2 to 5.2]). In the small families, the SMR was increased (SMR 1.5 [95% CI: 1.3 to 1.6]) [corrected] and excess mortality was observed between 10 and 39 years (SMR 3.2 [95% CI: 2.3 to 4.3]) and 50 and 59 years (SMR 1.9 [95% CI: 1.4 to 2.5]).

Conclusions: We identified specific age categories with increased mortality risks in HCM families. The small, referred pedigrees had higher mortality risks than the large 200-year multigenerational pedigrees. Our findings support the strategy of starting cardiological and genetic screening in the first-degree relatives of a proband from 10 years onward and including persons in the screening at least until the age of 60 years. Screening of more distant relatives is probably most efficient between 10 and 19 years.
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http://dx.doi.org/10.1016/j.jacc.2011.07.044DOI Listing
November 2011

High yield of LMNA mutations in patients with dilated cardiomyopathy and/or conduction disease referred to cardiogenetics outpatient clinics.

Am Heart J 2007 Dec 14;154(6):1130-9. Epub 2007 Sep 14.

Department of Genetics, University Medical Center Groningen, University of Groningen, The Netherlands.

Background: Among the most frequently encountered mutations in dilated cardiomyopathy (DCM) are those in the lamin A/C (LMNA) gene. Our goal was to analyze the LMNA gene in patients with DCM and/or conduction disease referred to the cardiogenetics outpatient clinic and to evaluate the prevalence of LMNA mutations and their clinical expression.

Methods And Results: The LMNA gene was screened in 61 index patients. Eleven mutations (including 6 novel) were identified, mainly in the subgroup of familial DCM with cardiac conduction disease (3/10 index patients) and in patients with DCM and Emery-Dreifuss, Limb-Girdle, or unclassified forms of muscular dystrophy (7/8 index patients). In addition, a mutation was identified in 1 of 4 families with only cardiac conduction disease. We did not identify any large deletions or duplications. Genotype-phenotype relationships revealed a high rate of sudden death and cardiac transplants in carriers of the p.N195K mutation. Our study confirmed that the p.R225X mutation leads to cardiac conduction disease with late or no development of DCM, underscoring the importance of this mutation in putative familial "lone conduction disease." Nearly one third of LMNA mutation carriers had experienced a thromboembolic event.

Conclusions: This study highlights the role of LMNA mutations in DCM and related disorders. A severe phenotype in p.N195K mutation carriers and preferential cardiac conduction disease in p.R225X carriers was encountered. Because of the clinical variability, including the development of associated symptoms in time, LMNA screening should be considered in patients with DCM or familial lone conduction disease.
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http://dx.doi.org/10.1016/j.ahj.2007.07.038DOI Listing
December 2007

Neonatal paroxysmal trismus and camptodactyly: the Crisponi syndrome.

Am J Med Genet A 2005 Feb;133A(1):90-2

Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.

The Crisponi syndrome is an infrequently described syndrome characterized by extensive muscular contractions in the face after even minimal stimuli, hypertonia, camptodactyly, and typical facial features (chubby cheeks, broad nose with anteverted nares, and long philtrum). Most patients have died in the first months of life due to hyperthermia. The syndrome has been described in Italians only; the inheritance pattern is most probably autosomal recessive. Here we describe a 4-year-old boy of Portuguese descent with this entity. Polysomnography during a paroxysmal muscle contraction showed severe obstructive breathing pattern. The overall breathing pattern outside the attacks showed a bizarre mix of disorders of control of breathing with central apneas, hypopnea, obstructive apneas, and long periods of expiratory apneas while the boy was awake. The hyperexcitability disappeared in the course of the first year of life. With time it became clear that he was developmentally delayed. A short review is provided, and the resemblance with the Stuve-Wiedemann syndrome is stressed.
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http://dx.doi.org/10.1002/ajmg.a.30536DOI Listing
February 2005