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Jiang C, Zhang Y. Current updates on arrhythmia within Timothy syndrome: genetics, mechanisms and therapeutics. Expert Rev Mol Med 2023; 25:e17. [PMID: 37132248 PMCID: PMC10407238 DOI: 10.1017/erm.2023.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/13/2023] [Accepted: 04/23/2023] [Indexed: 05/04/2023]
Abstract
Timothy syndrome (TS), characterised by multiple system malfunction especially the prolonged corrected QT interval and synchronised appearance of hand/foot syndactyly, is an extremely rare disease affecting early life with devastating arrhythmia. In this work, firstly, the various mutations in causative gene CACNA1C encoding cardiac L-type voltage-gated calcium channel (LTCC), regard with the genetic pathogeny and nomenclature of TS are reviewed. Secondly, the expression profile and function of CACNA1C gene encoding Cav1.2 proteins, and its gain-of-function mutation in TS leading to multiple organ disease phenotypes especially arrhythmia are discussed. More importantly, we focus on the altered molecular mechanism underlying arrhythmia in TS, and discuss about how LTCC malfunction in TS can cause disorganised calcium handling with excessive intracellular calcium and its triggered dysregulated excitation-transcription coupling. In addition, current therapeutics for TS cardiac phenotypes including LTCC blockers, beta-adrenergic blocking agents, sodium channel blocker, multichannel inhibitors and pacemakers are summarised. Eventually, the research strategy using patient-specific induced pluripotent stem cells is recommended as one of the promising future directions for developing therapeutic approaches. This review updates our understanding on the research progress and future avenues to study the genetics and molecular mechanism underlying the pathogenesis of devastating arrhythmia within TS, and provides novel insights for developing therapeutic measures.
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Affiliation(s)
- Congshan Jiang
- National Regional Children's Medical Centre (Northwest), Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province, Xi'an Key Laboratory of Children's Health and Diseases, Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710003, China
| | - Yanmin Zhang
- National Regional Children's Medical Centre (Northwest), Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province, Xi'an Key Laboratory of Children's Health and Diseases, Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710003, China
- Department of Cardiology, Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710003, China
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2
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Levy RJ, Timothy KW, Underwood JFG, Hall J, Bernstein JA, Pașca SP. A Cross-Sectional Study of the Neuropsychiatric Phenotype of CACNA1C-Related Disorder. Pediatr Neurol 2023; 138:101-106. [PMID: 36436328 DOI: 10.1016/j.pediatrneurol.2022.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/26/2022] [Accepted: 10/29/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND CACNA1C encodes the voltage-gated L-type calcium channel CaV1.2. A specific gain-of-function pathogenic variant in CACNA1C causes Timothy syndrome type 1 (TS1) with cardiac long QT syndrome, syndactyly, and neuropsychiatric symptoms. Our previous work found that the TS1 mutation alters neuronal activity-dependent signaling and interneuron migration. Recent case series highlighted a broader spectrum of CACNA1C-related disorder (CRD) that includes isolated cardiac disease, isolated neurologic deficits, and TS, but it is unknown how the clinical presentation of other CRD variants relates to neural defects. We surveyed individuals with CRD to define the neuropsychiatric and developmental phenotype in an effort to guide future research into the role of calcium channels in neural development. METHODS Caregivers of and individuals with CRD completed an online survey of pre- and perinatal events, cardiac events, developmental milestones, neuropsychiatric symptoms, and neuropsychiatric diagnoses. Multiple Mann-Whitney tests were used for comparison of categorical values and Fisher exact test for comparison of categorical variables between participants with and without cardiac arrhythmia. RESULTS Twenty-four participants with germline CACNA1C variants including TS1 completed the survey. The most common neuropsychiatric symptoms and/or diagnoses were developmental delay in 92%, incoordination in 71%, hypotonia in 67%, autism spectrum disorder in 50% (autistic features in 92%), seizures in 37.5%, and attention-deficit/hyperactivity disorder in 21% of participants. There were no significant differences in symptoms between participants with and without arrhythmia. CONCLUSIONS In our CRD cohort, there was an increased prevalence of multiple neuropsychiatric symptoms compared with the general population. These findings indicate the key role of CaV1.2 in brain development and the clinical importance of screening and therapeutically addressing neuropsychiatric symptoms in all individuals with CRD. Future directions include deep phenotyping of neuropsychiatric symptoms and efforts to relate these symptoms to cellular defects.
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Affiliation(s)
- Rebecca J Levy
- Division of Medical Genetics in the Department of Pediatrics, Stanford University, Stanford, California; Division of Child Neurology in the Department of Neurology, Stanford University, Stanford, California
| | | | - Jack F G Underwood
- Neuroscience & Mental Health Innovation Institute, Cardiff University, Cardiff, Wales, UK
| | - Jeremy Hall
- Neuroscience & Mental Health Innovation Institute, Cardiff University, Cardiff, Wales, UK
| | - Jonathan A Bernstein
- Division of Medical Genetics in the Department of Pediatrics, Stanford University, Stanford, California.
| | - Sergiu P Pașca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California; Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute and Bio-X, Stanford University, Stanford, California.
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Mironova GY, Haghbin N, Welsh DG. Functional tuning of Vascular L-type Ca2+ channels. Front Physiol 2022; 13:1058744. [DOI: 10.3389/fphys.2022.1058744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
Vascular smooth muscle contraction is intimately tied to membrane potential and the rise in intracellular Ca2+ enabled by the opening of L-type Ca2+ channels. While voltage is often viewed as the single critical factor gating these channels, research is starting to reveal a more intricate scenario whereby their function is markedly tuned. This emerging concept will be the focus of this three-part review, the first part articulating the mechanistic foundation of contractile development in vascular smooth muscle. Part two will extend this foundational knowledge, introducing readers to functional coupling and how neighboring L-type Ca2+ channels work cooperatively through signaling protein complexes, to facilitate their open probability. The final aspect of this review will discuss the impact of L-type Ca2+ channel trafficking, a process tied to cytoskeleton dynamics. Cumulatively, this brief manuscript provides new insight into how voltage, along with channel cooperativity and number, work in concert to tune Ca2+ responses and smooth muscle contraction.
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Zhao J, Segura E, Marsolais M, Parent L. A CACNA1C variant associated with cardiac arrhythmias provides mechanistic insights in the calmodulation of L-type Ca 2+ channels. J Biol Chem 2022; 298:102632. [PMID: 36273583 PMCID: PMC9691931 DOI: 10.1016/j.jbc.2022.102632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/12/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
We recently reported the identification of a de novo single nucleotide variant in exon 9 of CACNA1C associated with prolonged repolarization interval. Recombinant expression of the glycine to arginine variant at position 419 produced a gain in the function of the L-type CaV1.2 channel with increased peak current density and activation gating but without significant decrease in the inactivation kinetics. We herein reveal that these properties are replicated by overexpressing calmodulin (CaM) with CaV1.2 WT and are reversed by exposure to the CaM antagonist W-13. Phosphomimetic (T79D or S81D), but not phosphoresistant (T79A or S81A), CaM surrogates reproduced the impact of CaM WT on the function of CaV1.2 WT. The increased channel activity of CaV1.2 WT following overexpression of CaM was found to arise in part from enhanced cell surface expression. In contrast, the properties of the variant remained unaffected by any of these treatments. CaV1.2 substituted with the α-helix breaking proline residue were more reluctant to open than CaV1.2 WT but were upregulated by phosphomimetic CaM surrogates. Our results indicate that (1) CaM and its phosphomimetic analogs promote a gain in the function of CaV1.2 and (2) the structural properties of the first intracellular linker of CaV1.2 contribute to its CaM-induced modulation. We conclude that the CACNA1C clinical variant mimics the increased activity associated with the upregulation of CaV1.2 by Ca2+-CaM, thus maintaining a majority of channels in a constitutively active mode that could ultimately promote ventricular arrhythmias.
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Affiliation(s)
- Juan Zhao
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Emilie Segura
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Mireille Marsolais
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Lucie Parent
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada,For correspondence: Lucie Parent
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The Oxidative Balance Orchestrates the Main Keystones of the Functional Activity of Cardiomyocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7714542. [PMID: 35047109 PMCID: PMC8763515 DOI: 10.1155/2022/7714542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 11/03/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
This review is aimed at providing an overview of the key hallmarks of cardiomyocytes in physiological and pathological conditions. The main feature of cardiac tissue is the force generation through contraction. This process requires a conspicuous energy demand and therefore an active metabolism. The cardiac tissue is rich of mitochondria, the powerhouses in cells. These organelles, producing ATP, are also the main sources of ROS whose altered handling can cause their accumulation and therefore triggers detrimental effects on mitochondria themselves and other cell components thus leading to apoptosis and cardiac diseases. This review highlights the metabolic aspects of cardiomyocytes and wanders through the main systems of these cells: (a) the unique structural organization (such as different protein complexes represented by contractile, regulatory, and structural proteins); (b) the homeostasis of intracellular Ca2+ that represents a crucial ion for cardiac functions and E-C coupling; and (c) the balance of Zn2+, an ion with a crucial impact on the cardiovascular system. Although each system seems to be independent and finely controlled, the contractile proteins, intracellular Ca2+ homeostasis, and intracellular Zn2+ signals are strongly linked to each other by the intracellular ROS management in a fascinating way to form a "functional tetrad" which ensures the proper functioning of the myocardium. Nevertheless, if ROS balance is not properly handled, one or more of these components could be altered resulting in deleterious effects leading to an unbalance of this "tetrad" and promoting cardiovascular diseases. In conclusion, this "functional tetrad" is proposed as a complex network that communicates continuously in the cardiomyocytes and can drive the switch from physiological to pathological conditions in the heart.
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Ahern BM, Sebastian A, Levitan BM, Goh J, Andres DA, Satin J. L-type channel inactivation balances the increased peak calcium current due to absence of Rad in cardiomyocytes. J Gen Physiol 2021; 153:212476. [PMID: 34269819 PMCID: PMC8289690 DOI: 10.1085/jgp.202012854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/25/2021] [Indexed: 12/15/2022] Open
Abstract
The L-type Ca2+ channel (LTCC) provides trigger calcium to initiate cardiac contraction in a graded fashion that is regulated by L-type calcium current (ICa,L) amplitude and kinetics. Inactivation of LTCC is controlled to fine-tune calcium flux and is governed by voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). Rad is a monomeric G protein that regulates ICa,L and has recently been shown to be critical to β-adrenergic receptor (β-AR) modulation of ICa,L. Our previous work showed that cardiomyocyte-specific Rad knockout (cRadKO) resulted in elevated systolic function, underpinned by an increase in peak ICa,L, but without pathological remodeling. Here, we sought to test whether Rad-depleted LTCC contributes to the fight-or-flight response independently of β-AR function, resulting in ICa,L kinetic modifications to homeostatically balance cardiomyocyte function. We recorded whole-cell ICa,L from ventricular cardiomyocytes from inducible cRadKO and control (CTRL) mice. The kinetics of ICa,L stimulated with isoproterenol in CTRL cardiomyocytes were indistinguishable from those of unstimulated cRadKO cardiomyocytes. CDI and VDI are both enhanced in cRadKO cardiomyocytes without differences in action potential duration or QT interval. To confirm that Rad loss modulates LTCC independently of β-AR stimulation, we crossed a β1,β2-AR double-knockout mouse with cRadKO, resulting in a Rad-inducible triple-knockout mouse. Deletion of Rad in cardiomyocytes that do not express β1,β2-AR still yielded modulated ICa,L and elevated basal heart function. Thus, in the absence of Rad, increased Ca2+ influx is homeostatically balanced by accelerated CDI and VDI. Our results indicate that the absence of Rad can modulate the LTCC without contribution of β1,β2-AR signaling and that Rad deletion supersedes β-AR signaling to the LTCC to enhance in vivo heart function.
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Affiliation(s)
- Brooke M Ahern
- Department of Physiology, University of Kentucky, Lexington, KY
| | | | - Bryana M Levitan
- Department of Physiology, University of Kentucky, Lexington, KY.,Gill Heart and Vascular Institute, University of Kentucky, Lexington, KY
| | - Jensen Goh
- Department of Physiology, University of Kentucky, Lexington, KY
| | - Douglas A Andres
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY
| | - Jonathan Satin
- Department of Physiology, University of Kentucky, Lexington, KY
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7
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Freitag CM, Chiocchetti AG, Haslinger D, Yousaf A, Waltes R. [Genetic risk factors and their influence on neural development in autism spectrum disorders]. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2021; 50:187-202. [PMID: 34128703 DOI: 10.1024/1422-4917/a000803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Genetic risk factors and their influence on neural development in autism spectrum disorders Abstract. Abstract. Autism spectrum disorders are etiologically based on genetic and specific gene x biologically relevant environmental risk factors. They are diagnosed based on behavioral characteristics, such as impaired social communication and stereotyped, repetitive behavior and sensory as well as special interests. The genetic background is heterogeneous, i. e., it comprises diverse genetic risk factors across the disorder and high interindividual differences of specific genetic risk factors. Nevertheless, risk factors converge regarding underlying biological mechanisms and shared pathways, which likely cause the autism-specific behavioral characteristics. The current selective literature review summarizes differential genetic risk factors and focuses particularly on mechanisms and pathways currently being discussed by international research. In conclusion, clinically relevant aspects and open translational research questions are presented.
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Affiliation(s)
- Christine M Freitag
- Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Universitätsklinikum Frankfurt, Goethe-Universität, Frankfurt am Main
| | - Andreas G Chiocchetti
- Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Universitätsklinikum Frankfurt, Goethe-Universität, Frankfurt am Main
| | - Denise Haslinger
- Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Universitätsklinikum Frankfurt, Goethe-Universität, Frankfurt am Main
| | - Afsheen Yousaf
- Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Universitätsklinikum Frankfurt, Goethe-Universität, Frankfurt am Main
| | - Regina Waltes
- Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Universitätsklinikum Frankfurt, Goethe-Universität, Frankfurt am Main
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Nascimento E, Tinoco CF, Silva CD, Cortez FFM, Kaufman R. Aborted Sudden Death Due to Severe Ventricular Arrhythmia in Timothy Syndrome. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2021. [DOI: 10.36660/ijcs.20200061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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9
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Detection of a DNA Methylation Signature for the Intellectual Developmental Disorder, X-Linked, Syndromic, Armfield Type. Int J Mol Sci 2021; 22:ijms22031111. [PMID: 33498634 PMCID: PMC7865843 DOI: 10.3390/ijms22031111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022] Open
Abstract
A growing number of genetic neurodevelopmental disorders are known to be associated with unique genomic DNA methylation patterns, called episignatures, which are detectable in peripheral blood. The intellectual developmental disorder, X-linked, syndromic, Armfield type (MRXSA) is caused by missense variants in FAM50A. Functional studies revealed the pathogenesis to be a spliceosomopathy that is characterized by atypical mRNA processing during development. In this study, we assessed the peripheral blood specimens in a cohort of individuals with MRXSA and detected a unique and highly specific DNA methylation episignature associated with this disorder. We used this episignature to construct a support vector machine model capable of sensitive and specific identification of individuals with pathogenic variants in FAM50A. This study contributes to the expanding number of genetic neurodevelopmental disorders with defined DNA methylation episignatures, provides an additional understanding of the associated molecular mechanisms, and further enhances our ability to diagnose patients with rare disorders.
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Bauer R, Timothy KW, Golden A. Update on the Molecular Genetics of Timothy Syndrome. Front Pediatr 2021; 9:668546. [PMID: 34079780 PMCID: PMC8165229 DOI: 10.3389/fped.2021.668546] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022] Open
Abstract
Timothy Syndrome (TS) (OMIM #601005) is a rare autosomal dominant syndrome caused by variants in CACNA1C, which encodes the α1C subunit of the voltage-gated calcium channel Cav1.2. TS is classically caused by only a few different genetic changes and characterized by prolonged QT interval, syndactyly, and neurodevelopmental delay; however, the number of identified TS-causing variants is growing, and the resulting symptom profiles are incredibly complex and variable. Here, we aim to review the genetic and clinical findings of all published case reports of TS to date. We discuss multiple possible mechanisms for the variability seen in clinical features across these cases, including mosaicism, genetic background, isoform complexity of CACNA1C and differential expression of transcripts, and biophysical changes in mutant CACNA1C channels. Finally, we propose future research directions such as variant validation, in vivo modeling, and natural history characterization.
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Affiliation(s)
- Rosemary Bauer
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | | | - Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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11
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Nugud AA, ELkholy NM, Omar AA, Qazi A, Tzivinikos C, Chencheri N, Khan S, Ba'Ath ME. Case Report: Expanding the Phenotypic Spectrum of Timothy Syndrome Type 1: A Sporadic Case With a de novo CACNA1C Pathogenic Variant and Segmental Ileal Dilatation. Front Pediatr 2021; 9:634655. [PMID: 33987151 PMCID: PMC8110704 DOI: 10.3389/fped.2021.634655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 04/06/2021] [Indexed: 11/30/2022] Open
Abstract
Background: Long QT syndactyly syndrome (long QT syndrome type 8), also known as Timothy Syndrome (TS) was first described in 1994 with still <50 case reported in the literature. The full spectrum of the syndrome is not yet known. Results: Here we report a girl who presented with new onset refractory seizures and an undiagnosed cause of intermittent abdominal distention. She also had syndactyly of her fingers and toes and was found to have prolonged QT. Upon further investigations she was found to have a de novo pathogenic variant in CACNA1C, along with Segmental Ileal Dilatation (SID), and subsequently diagnosed with Timothy syndrome. Conclusion: To our knowledge, the association of Timothy Syndrome with Segmental Ileal Dilatation, was not described before.
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Affiliation(s)
- Ahmed A Nugud
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates
| | | | - Awad Alkarim Omar
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates
| | - Abid Qazi
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates
| | - Christos Tzivinikos
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates.,Department of Clinical Sciences, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | | | - Sabina Khan
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates
| | - Muhammad Eyad Ba'Ath
- Al Jalila Children's Speciality Hospital, Dubai, United Arab Emirates.,Department of Clinical Sciences, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
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Marcantoni A, Calorio C, Hidisoglu E, Chiantia G, Carbone E. Cav1.2 channelopathies causing autism: new hallmarks on Timothy syndrome. Pflugers Arch 2020; 472:775-789. [PMID: 32621084 DOI: 10.1007/s00424-020-02430-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
Cav1.2 L-type calcium channels play key roles in long-term synaptic plasticity, sensory transduction, muscle contraction, and hormone release. De novo mutations in the gene encoding Cav1.2 (CACNA1C) causes two forms of Timothy syndrome (TS1, TS2), characterized by a multisystem disorder inclusive of cardiac arrhythmias, long QT, autism, and adrenal gland dysfunction. In both TS1 and TS2, the missense mutation G406R is on the alternatively spliced exon 8 and 8A coding for the IS6-helix of Cav1.2 and is responsible for the penetrant form of autism in most TS individuals. The mutation causes specific gain-of-function changes to Cav1.2 channel gating: a "leftward shift" of voltage-dependent activation, reduced voltage-dependent inactivation, and a "leftward shift" of steady-state inactivation. How this occurs and how Cav1.2 gating changes alter neuronal firing and synaptic plasticity is still largely unexplained. Trying to better understanding the molecular basis of Cav1.2 gating dysfunctions leading to autism, here, we will present and discuss the properties of recently reported typical and atypical TS phenotypes and the effective gating changes exhibited by missense mutations associated with long QTs without extracardiac symptoms, unrelated to TS. We will also discuss new emerging views achieved from using iPSCs-derived neurons and the newly available autistic TS2-neo mouse model, both appearing promising for understanding neuronal mistuning in autistic TS patients. We will also analyze and describe recent proposals of molecular pathways that might explain mistuned Ca2+-mediated and Ca2+-independent excitation-transcription signals to the nucleus. Briefly, we will also discuss possible pharmacological approaches to treat autism associated with L-type channelopathies.
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Affiliation(s)
- Andrea Marcantoni
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Chiara Calorio
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Enis Hidisoglu
- Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey
| | - Giuseppe Chiantia
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Emilio Carbone
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy.
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D'Adamo MC, Liantonio A, Conte E, Pessia M, Imbrici P. Ion Channels Involvement in Neurodevelopmental Disorders. Neuroscience 2020; 440:337-359. [PMID: 32473276 DOI: 10.1016/j.neuroscience.2020.05.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/16/2020] [Accepted: 05/19/2020] [Indexed: 12/14/2022]
Abstract
Inherited and sporadic mutations in genes encoding for brain ion channels, affecting membrane expression or biophysical properties, have been associated with neurodevelopmental disorders characterized by epilepsy, cognitive and behavioral deficits with significant phenotypic and genetic heterogeneity. Over the years, the screening of a growing number of patients and the functional characterization of newly identified mutations in ion channels genes allowed to recognize new phenotypes and to widen the clinical spectrum of known diseases. Furthermore, advancements in understanding disease pathogenesis at atomic level or using patient-derived iPSCs and animal models have been pivotal to orient therapeutic intervention and to put the basis for the development of novel pharmacological options for drug-resistant disorders. In this review we will discuss major improvements and critical issues concerning neurodevelopmental disorders caused by dysfunctions in brain sodium, potassium, calcium, chloride and ligand-gated ion channels.
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Affiliation(s)
- Maria Cristina D'Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta
| | | | - Elena Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy
| | - Mauro Pessia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta; Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Italy.
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