Browsing by Author "Ackerman, Michael J."

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    Calmodulin mutations and life-threatening cardiac arrhythmias: insights from the International Calmodulinopathy Registry
    (Oxford University Press, 2016-06-06) Crotti, Lia; Spazzolini, Carla; Tester, David J; Ghidoni, Alice; Baruteau, Alban-Elouen; Beckmann, Britt-Maria; Behr, Elijah R; Bennett, Jeffrey S; Bezzina, Connie R; Bhuiyan, Zahurul A; Celiker, Alpay; Cerrone, Marina; Dagradi, Federica; De Ferrari, Gaetano M; Etheridge, Susan P; Fatah, Meena; Garcia-Pavia, Pablo; Al-Ghamdi, Saleh; Hamilton, Robert M; Al-Hassnan, Zuhair N; Horie, Minoru; Jimenez-Jaimez, Juan; Kanter, Ronald J.; Kaski, Juan P.; Kotta, Maria-Christina; Lahrouchi, Najim; Makita, Naomasa; Norrish, Gabrielle; Odland, Hans H.; Ohno, Seiko; Papagiannis, John; Parati, Gianfranco; Sekarski, Nicole; Tveten, Kristian; Vatta, Matteo; Webster, Gregory; Wilde, Arthur A. M.; Wojciak, Julianne; George, Alfred L., Jr; Ackerman, Michael J.; Schwartz, Peter J.; Medical and Molecular Genetics, School of Medicine
    Aims Calmodulinopathies are rare life-threatening arrhythmia syndromes which affect mostly young individuals and are, caused by mutations in any of the three genes (CALM 1–3) that encode identical calmodulin proteins. We established the International Calmodulinopathy Registry (ICalmR) to understand the natural history, clinical features, and response to therapy of patients with a CALM-mediated arrhythmia syndrome. Methods and results A dedicated Case Report File was created to collect demographic, clinical, and genetic information. ICalmR has enrolled 74 subjects, with a variant in the CALM1 (n = 36), CALM2 (n = 23), or CALM3 (n = 15) genes. Sixty-four (86.5%) were symptomatic and the 10-year cumulative mortality was 27%. The two prevalent phenotypes are long QT syndrome (LQTS; CALM-LQTS, n = 36, 49%) and catecholaminergic polymorphic ventricular tachycardia (CPVT; CALM-CPVT, n = 21, 28%). CALM-LQTS patients have extremely prolonged QTc intervals (594 ± 73 ms), high prevalence (78%) of life-threatening arrhythmias with median age at onset of 1.5 years [interquartile range (IQR) 0.1–5.5 years] and poor response to therapies. Most electrocardiograms (ECGs) show late onset peaked T waves. All CALM-CPVT patients were symptomatic with median age of onset of 6.0 years (IQR 3.0–8.5 years). Basal ECG frequently shows prominent U waves. Other CALM-related phenotypes are idiopathic ventricular fibrillation (IVF, n = 7), sudden unexplained death (SUD, n = 4), overlapping features of CPVT/LQTS (n = 3), and predominant neurological phenotype (n = 1). Cardiac structural abnormalities and neurological features were present in 18 and 13 patients, respectively. Conclusion Calmodulinopathies are largely characterized by adrenergically-induced life-threatening arrhythmias. Available therapies are disquietingly insufficient, especially in CALM-LQTS. Combination therapy with drugs, sympathectomy, and devices should be considered.
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    A Case for Inclusion of Genetic Counselors in Cardiac Care
    (Wolters Kluwer, 2016-03) Arscott, Patricia; Caleshu, Colleen; Kotzer, Katrina; Kreykes, Sarah; Kruisselbrink, Teresa; Orland, Kate; Rigelsky, Christina; Smith, Emily; Spoonamore, Katherine; Larsen Haidle, Joy; Marvin, Monica; Ackerman, Michael J.; Hadi, Azam; Mani, Arya; Ommen, Steven; Cherny, Sara; Department of Medicine, IU School of Medicine
    Recent advances in genetic testing for heritable cardiac diseases have led to an increasing involvement of the genetic counselor in cardiology practice. We present a series of cases collected from a nationwide query of genetics professionals regarding issues related to cost and utilization of genetic testing. Three themes emerged across cases: (1) choosing the most appropriate genetic test, (2) choosing the best person to test, and (3) interpreting results accurately. These cases demonstrate that involvement of a genetic counselor throughout the evaluation, diagnosis, and continuing management of individuals and families with inherited cardiovascular conditions helps to promote the efficient use of healthcare dollars.
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    Clinical presentation of calmodulin mutations: the International Calmodulinopathy Registry
    (Oxford University Press, 2023) Crotti, Lia; Spazzolini, Carla; Nyegaard, Mette; Overgaard, Michael T.; Kotta, Maria-Christina; Dagradi, Federica; Sala, Luca; Aiba, Takeshi; Ayers, Mark D.; Baban, Anwar; Barc, Julien; Beach, Cheyenne M.; Behr, Elijah R.; Bos, J. Martijn; Cerrone, Marina; Covi, Peter; Cuneo, Bettina; Denjoy, Isabelle; Donner, Birgit; Elbert, Adrienne; Eliasson, Håkan; Etheridge, Susan P.; Fukuyama, Megumi; Girolami, Francesca; Hamilton, Robert; Horie, Minoru; Iascone, Maria; Jiménez-Jaimez, Juan; Jensen, Henrik Kjærulf; Kannankeril, Prince J.; Kaski, Juan P.; Makita, Naomasa; Muñoz-Esparza, Carmen; Odland, Hans H.; Ohno, Seiko; Papagiannis, John; Porretta, Alessandra Pia; Prandstetter, Christopher; Probst, Vincent; Robyns, Tomas; Rosenthal, Eric; Rosés-Noguer, Ferran; Sekarski, Nicole; Singh, Anoop; Spentzou, Georgia; Stute, Fridrike; Tfelt-Hansen, Jacob; Till, Jan; Tobert, Kathryn E.; Vinocur, Jeffrey M.; Webster, Gregory; Wilde, Arthur A. M.; Wolf, Cordula M.; Ackerman, Michael J.; Schwartz, Peter J.; Pediatrics, School of Medicine
    Aims: Calmodulinopathy due to mutations in any of the three CALM genes (CALM1-3) causes life-threatening arrhythmia syndromes, especially in young individuals. The International Calmodulinopathy Registry (ICalmR) aims to define and link the increasing complexity of the clinical presentation to the underlying molecular mechanisms. Methods and results: The ICalmR is an international, collaborative, observational study, assembling and analysing clinical and genetic data on CALM-positive patients. The ICalmR has enrolled 140 subjects (median age 10.8 years [interquartile range 5-19]), 97 index cases and 43 family members. CALM-LQTS and CALM-CPVT are the prevalent phenotypes. Primary neurological manifestations, unrelated to post-anoxic sequelae, manifested in 20 patients. Calmodulinopathy remains associated with a high arrhythmic event rate (symptomatic patients, n = 103, 74%). However, compared with the original 2019 cohort, there was a reduced frequency and severity of all cardiac events (61% vs. 85%; P = .001) and sudden death (9% vs. 27%; P = .008). Data on therapy do not allow definitive recommendations. Cardiac structural abnormalities, either cardiomyopathy or congenital heart defects, are present in 30% of patients, mainly CALM-LQTS, and lethal cases of heart failure have occurred. The number of familial cases and of families with strikingly different phenotypes is increasing. Conclusion: Calmodulinopathy has pleiotropic presentations, from channelopathy to syndromic forms. Clinical severity ranges from the early onset of life-threatening arrhythmias to the absence of symptoms, and the percentage of milder and familial forms is increasing. There are no hard data to guide therapy, and current management includes pharmacological and surgical antiadrenergic interventions with sodium channel blockers often accompanied by an implantable cardioverter-defibrillator.
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    International Criteria for Electrocardiographic Interpretation in Athletes
    (Elsevier, 2017-02) Sharma, Sanjay; Drezner, Jonathan A.; Baggish, Aaron; Papadakis, Michael; Wilson, Mathew G.; Prutkin, Jordan M.; La Gerche, Andre; Ackerman, Michael J.; Borjesson, Mats; Salerno, Jack C.; Asif, Irfan M.; Owens, David S.; Chung, Eugene H.; Emery, Michael S.; Froelicher, Victor F.; Heidbuchel, Hein; Adamuz, Carmen; Asplund, Chad A.; Cohen, Gordon; Harmon, Kimberly G.; Marek, Joseph C.; Molossi, Silvana; Niebauer, Josef; Pelto, Hank F.; Perez, Marco V.; Riding, Nathan R.; Saarel, Tess; Schmied, Christian M.; Shipon, David M.; Stein, Ricardo; Vetter, Victoria L.; Pelliccia, Antonio; Corrado, Domenico; Medicine, School of Medicine
    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural, or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly over the last decade; pushed by a growing body of scientific data that both tests proposed criteria sets and establishes new evidence to guide refinements. On February 26-27, 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington, to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.
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    Loss of function of hNav1.5 by a ZASP1 mutation associated with intraventricular conduction disturbances in left ventricular noncompaction
    (Ovid Technologies Wolters Kluwer -American Heart Association, 2012-10) Xi, Yutao; Ai, Tomohiko; De Lange, Enno; Li, Zhaohui; Wu, Geru; Brunelli, Luca; Kyle, W. Buck; Turker, Isik; Cheng, Jie; Ackerman, Michael J.; Kimura, Akinori; Weiss, James N.; Qu, Zhilin; Kim, Jeffrey J.; Faulkner, Georgine; Vatta, Matteo; Department of Medicine, IU School of Medicine
    BACKGROUND: Defects of cytoarchitectural proteins can cause left ventricular noncompaction, which is often associated with conduction system diseases. We have previously identified a p.D117N mutation in the LIM domain-binding protein 3-encoding Z-band alternatively spliced PDZ motif gene (ZASP) in a patient with left ventricular noncompaction and conduction disturbances. We sought to investigate the role of p.D117N mutation in the LBD3 NM_001080114.1 isoform (ZASP1-D117N) for the regulation of cardiac sodium channel (Na(v)1.5) that plays an important role in the cardiac conduction system. METHODS AND RESULTS: Effects of ZASP1-wild-type and ZASP1-D117N on Na(v)1.5 were studied in human embryonic kidney-293 cells and neonatal rat cardiomyocytes. Patch-clamp study demonstrated that ZASP1-D117N significantly attenuated I(Na) by 27% in human embryonic kidney-293 cells and by 32% in neonatal rat cardiomyocytes. In addition, ZASP1-D117N rightward shifted the voltage-dependent activation and inactivation in both systems. In silico simulation using Luo-Rudy phase 1 model demonstrated that altered Na(v)1.5 function can reduce cardiac conduction velocity by 28% compared with control. Pull-down assays showed that both wild-type and ZASP1-D117N can complex with Na(v)1.5 and telethonin/T-Cap, which required intact PDZ domains. Immunohistochemical staining in neonatal rat cardiomyocytes demonstrates that ZASP1-D117N did not significantly disturb the Z-line structure. Disruption of cytoskeletal networks with 5-iodonaphthalene-1-sulfonyl homopiperazine and cytochalasin D abolished the effects of ZASP1-D117N on Na(v)1.5. CONCLUSIONS: ZASP1 can form protein complex with telethonin/T-Cap and Na(v)1.5. The left ventricular noncompaction-specific ZASP1 mutation can cause loss of function of Na(v)1.5, without significant alteration of the cytoskeletal protein complex. Our study suggests that electric remodeling can occur in left ventricular noncompaction subject because of a direct effect of mutant ZASP on Na(v)1.5.
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    Novel Timothy Syndrome Mutation Leading to Increase in CACNA1C Window Current
    (Elsevier, 2015-01) Boczek, Nicole J.; Miller, Erin M.; Ye, Dan; Nesterenko, Vlad V.; Tester, David J.; Antzelevitch, Charles; Czosek, Richard J.; Ackerman, Michael J.; Ware, Stephanie M.; Department of Pediatrics, IU School of Medicine
    Background Timothy syndrome (TS) is a rare multisystem genetic disorder characterized by a myriad of abnormalities, including QT prolongation, syndactyly, and neurologic symptoms. The predominant genetic causes are recurrent de novo missense mutations in exon 8/8A of the CACNA1C-encoded L-type calcium channel; however, some cases remain genetically elusive. Objective The purpose of this study was to identify the genetic cause of TS in a patient who did not harbor a CACNA1C mutation in exon 8/A, and was negative for all other plausible genetic substrates. Methods Diagnostic exome sequencing was used to identify the genetic substrate responsible for our case of TS. The identified mutation was characterized using whole-cell patch-clamp technique, and the results of these analyses were modeled using a modified Luo–Rudy dynamic model to determine the effects on the cardiac action potential. Results Whole exome sequencing revealed a novel CACNA1C mutation, p.Ile1166Thr, in a young male with diagnosed TS. Functional electrophysiologic analysis identified a novel mechanism of TS-mediated disease, with an overall loss of current density and a gain-of-function shift in activation, leading to an increased window current. Modeling studies of this variant predicted prolongation of the action potential as well as the development of spontaneous early afterdepolarizations. Conclusion Through expanded whole exome sequencing, we identified a novel genetic substrate for TS, p.Ile1166Thr-CACNA1C. Electrophysiologic experiments combined with modeling studies have identified a novel TS mechanism through increased window current. Therefore, expanded genetic testing in cases of TS to the entire CACNA1C coding region, if initial targeted testing is negative, may be warranted.