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TRPM4 Mutation in Patients With Ventricular Noncompaction and Cardiac Conduction Disease

2018; Wolters Kluwer; Volume: 11; Issue: 5 Linguagem: Inglês

10.1161/circgen.118.002103

2574-8300

Yukihiro Saito, Kazufumi Nakamura, Nobuhiro Nishi, Osamu Igawa, Masashi Yoshida, Toru Miyoshi, Atsuyuki Watanabe, Hiroshi Morita, Hiroshi Ito,

Cardiac Structural Anomalies and Repair

HomeCirculation: Genomic and Precision MedicineVol. 11, No. 5TRPM4 Mutation in Patients With Ventricular Noncompaction and Cardiac Conduction Disease Free AccessCase ReportPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCase ReportPDF/EPUBTRPM4 Mutation in Patients With Ventricular Noncompaction and Cardiac Conduction Disease Yukihiro Saito, MD, PhD, Kazufumi Nakamura, MD, PhD, Nobuhiro Nishi, MD, PhD, Osamu Igawa, MD, PhD, Masashi Yoshida, MD, PhD, Toru Miyoshi, MD, PhD, Atsuyuki Watanabe, MD, PhD, Hiroshi Morita, MD, PhD and Hiroshi Ito, MD, PhD Yukihiro SaitoYukihiro Saito Departments of Cardiovascular Medicine (Y.S., K.N., T.M., A.W., H.I.) , Kazufumi NakamuraKazufumi Nakamura Departments of Cardiovascular Medicine (Y.S., K.N., T.M., A.W., H.I.) , Nobuhiro NishiNobuhiro Nishi Cardiovascular Therapeutics (N.N., H.M.) , Osamu IgawaOsamu Igawa Department of Internal Medicine and Cardiology, Nippon Medical School, Tama-Nagayama Hospital, Tokyo, Japan (O.I.). , Masashi YoshidaMasashi Yoshida Chronic Kidney Disease and Cardiovascular Disease (M.Y.), Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan , Toru MiyoshiToru Miyoshi Departments of Cardiovascular Medicine (Y.S., K.N., T.M., A.W., H.I.) , Atsuyuki WatanabeAtsuyuki Watanabe Departments of Cardiovascular Medicine (Y.S., K.N., T.M., A.W., H.I.) , Hiroshi MoritaHiroshi Morita Cardiovascular Therapeutics (N.N., H.M.) and Hiroshi ItoHiroshi Ito Departments of Cardiovascular Medicine (Y.S., K.N., T.M., A.W., H.I.) Originally published18 Jun 2018https://doi.org/10.1161/CIRCGEN.118.002103Circulation: Genomic and Precision Medicine. 2018;11:e002103IntroductionLeft ventricular noncompaction (LVNC) is characterized by abnormally prominent trabeculations and deep intertrabecular recesses in the left ventricle.1 LVNC can range from asymptomatic to end-stage heart failure and lethal arrhythmias, which lead to sudden cardiac death. Mutations associated with sarcomere proteins, ion channels, and developmental transcription factors have been identified in patients with LVNC.1The proband was diagnosed with incomplete right bundle branch block at 5 years old. At 16 years old, he was diagnosed with complete right bundle branch block and frequent premature ventricular contraction. At 25 years old, he was diagnosed with complete atrioventricular block and left ventricular dysfunction, and a permanent pacemaker was implanted. His echocardiogram exhibited prominent trabeculations and deep intertrabecular recesses in the apical to midventricular lateral wall. The noncompacted zone/compacted zone ratio was 2.3 (Figure A). Subsequently, symptoms of left ventricular dysfunction became progressively more severe despite medication and cardiac resynchronization therapy, and he eventually died of heart failure. The autopsy findings showed dilated ventricular lumen, whitish and filamentous prominent trabeculations in the ventricle, and thin compacted myocardium (Figure B). Microscopic findings showed displacement of the atrioventricular node by a fatty tissue (Figure C) and loss of the Purkinje fibers. Thickened endocardium and subendocardial fibrosis were seen, and fibrosis of trabeculae and interventricular septum were more prominent than previously reported cases.2 Mild anastomosing broad trabeculae and staghorn-like endocardial lined spaces were seen (Figure D). A fibrous band was not apparent. These findings were consistent with LVNC and progressive cardiac conduction defects. His younger brother and sister (II-2 and II-3 in Figure E) also had been diagnosed with LVNC by echocardiogram. Several years after diagnosis of LVNC, both of them developed complete atrioventricular block and received permanent pacemaker implantation. However, their parents (I-1 and I-2 in Figure E) did not have the same abnormality in their echocardiograms and electrocardiograms.Download figureDownload PowerPointFigure. The autopsy findings of the proband, the pedigree of the family, TRPM4 mutation, and effects of TRPM4 inhibitor on immature human cardiomyocytes.A, The echocardiogram exhibited noncompaction especially in the left ventricular apex. B, Macroscopic findings of the proband's left ventricle showed prominent trabeculations. C, Microscopic findings of proband's atrioventricular node using Masson trichrome staining showed displacement by a fatty tissue surrounded by dashed lines. D, Masson trichrome staining of the left ventricle showed thickened endocardium, subendocardial fibrosis, and anastomosing trabeculae. E, Squares/circles indicate male/female family members, respectively; black/white symbols represent affected/unaffected persons, respectively; a symbol with a slash represents deceased persons. +/− indicates harboring the heterozygous TRPM4 mutation and −/− indicates not harboring the mutation. The proband (II-1) is indicated by the arrow. F, The TRPM4 variant was confirmed by capillary sequencing. G, Reverse transcription polymerase chain reaction products from endomyocardial biopsy samples of affected family members showed another smaller size band (yellow arrowhead). H, Sequence of DNA fragment extracted from the smaller band showed exon 7 skipping. I, Exon 7 skipping leads to premature termination codon in exon 8, and truncated TRPM4 protein cannot form functional channels. J, TRPM4 mRNA levels were low in endomyocardial biopsy samples from affected family members compared with patients without structural heart abnormality. K, 10 μmol/L 9-phenanthrol reduced expression of HEY2, TBX5, and NKX2-5 in human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs; n=4 independent experiments; data are mean±SD). P values were determined by a Mann–Whitney U test. NSVT indicates nonsustained ventricular tachycardia; and PVC, premature ventricular contraction.Thus, we performed targeted gene panel sequencing with TruSight One sequencing panel on Miseq platform (Illumina, San Diego, CA) for genomic analysis of the coding regions of 4813 genes with a known associated clinical phenotype using genomic DNA samples from 4 family members who agreed to the genetic testing (I-1, I-2, II-1, and II-3). II-2 rejected the test. A heterozygous variant in the 3′ end of exon 7 of TRPM4 gene, c.858G>A, was identified (Figure F). Minor allele frequency of this variant was low in the sequencing databases: 0.0017, Human Genetic Variation Database version 2.3; and 0.00001651, Exome Aggregation Consortium version 0.3.1. This variant is a synonymous substitution, p.T286T. Although the produced amino acid sequence is not modified, this variant is in the conserved splice region sequence. Thus, we suspected transcription of abnormal mRNA caused by aberrant splicing.Next, RNA was extracted from endomyocardial biopsy samples of the proband (II-1), his sister (II-3), and 2 unrelated patients with arrhythmias. Amplification of the region including exon 7 of TRPM4 by reverse transcription polymerase chain reaction showed an additional smaller size band in affected members' samples (Figure G). Sequencing revealed that exon 6 was followed by exon 8—that is, sequence of exon 7 was skipped (Figure H). Skipping exon 7 results in a downstream frameshift and a premature termination codon in exon 8 and functional channels cannot be formed (Figure I). In addition, normal allele-derived TRPM4 mRNA levels in the affected members' samples were lower than those of unrelated patients (Figure J). These results indicated that this mutation might lead to loss of function by decrease in the amount of TRPM4 protein.When TRPM4 activity was inhibited by 9-phenanthrol in human induced pluripotent stem cells–derived cardiomyocytes obtained from a healthy subject, mRNA levels of HEY2, TBX5, and NKX2-5, transcription factors associated with development of the conduction system and the ventricle, were downregulated (Figure K). This suggests that reduced function in the TRPM4 channel in immature cardiomyocytes leads to changes in gene expression that could affect myocardial structures. Further studies are needed to clarify this point in vivo analysis.We found that the mutant allele containing the c.858G>A synonymous variant cannot produce functional protein, and the variant might lead to loss of function because of reduction of overall expression. Loss-of-function TRPM4 mutations associated with complete atrioventricular block have been reported recently,3 and TRPM4 knockout mice presented a conduction disturbance.4 The mother of the patients who harbors this mutation was well, therefore we hypothesized that loss of function caused by haploinsufficiency of TRPM4 is associated with autosomal dominant progressive cardiac conduction defects. The other potential target identified was a heterozygous missense variant of Desmoplakin (DSP), c.4886G>T, p.S1629I in mother (I-2), proband (II-1), and his sister (II-3). DSP has been reported to be associated with arrhythmogenic right/left ventricular cardiomyopathy and ventricular noncompaction and progressive cardiac conduction defects.5–7 Kapplinger et al7 previously reported genes associated with arrhythmogenic right ventricular cardiomyopathy, including DSP, finding that this variant was present in a healthy control. According to their report, DSP missense variants in non-white patients and outside the hot spot between residues 250 and 604 are less likely pathogenic. Thus, we decided to analyze the variant in TRPM4 because the missense variant in DSP was less likely pathogenic. It is possible that these patients have an additional homozygous or compound heterozygous mutation because their parents had structurally and electrophysiologically normal hearts; however, we could not find a candidate gene for an autosomal recessive disease in this study. Whole-exome or -genome sequencing would be useful to identify the additional pathogenic variant.In summary, we identified a loss-of-function mutation of TRPM4 in patients with LVNC complicated by progressive cardiac conduction defects.AcknowledgmentsWe thank Kaoru Akazawa, Wendy Knowlton, and members of Biobank in Okayama University Hospital and Central Research Laboratory in Okayama University Medical School for their excellent technical assistance.DisclosuresNone.Footnoteshttp://circgenetics.ahajournals.orgYukihiro Saito, MD, PhD or Kazufumi Nakamura, MD, PhD, Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700–8558, Japan, E-mail [email protected] or [email protected]References1. Towbin JA, Lorts A, Jefferies JL. Left ventricular non-compaction cardiomyopathy.Lancet. 2015; 386:813–825. doi: 10.1016/S0140-6736(14)61282-4.CrossrefMedlineGoogle Scholar2. Burke A, Mont E, Kutys R, Virmani R. Left ventricular noncompaction: a pathological study of 14 cases.Hum Pathol. 2005; 36:403–411. doi: 10.1016/j.humpath.2005.02.004.CrossrefMedlineGoogle Scholar3. Syam N, Chatel S, Ozhathil LC, Sottas V, Rougier JS, Baruteau A, et al. Variants of transient receptor potential melastatin member 4 in childhood atrioventricular block.J Am Heart Assoc. 2016; 5:e001625. doi: 10.1161/JAHA.114.001625.LinkGoogle Scholar4. Demion M, Thireau J, Gueffier M, Finan A, Khoueiry Z, Cassan C, et al. Trpm4 gene invalidation leads to cardiac hypertrophy and electrophysiological alterations.PLoS One. 2014; 9:e115256. doi: 10.1371/journal.pone.0115256.CrossrefMedlineGoogle Scholar5. Kiselev A, Mikhaylov E, Parmon E, Sjoberg G, Sejersen T, Tarnovskaya S, et al. Progressive cardiac conduction disease associated with a DSP gene mutation.Int J Cardiol. 2016; 216:188–189. doi: 10.1016/j.ijcard.2016.04.164.CrossrefMedlineGoogle Scholar6. 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Amarouch M, El Hilaly J and Yu H (2020) Inherited Cardiac Arrhythmia Syndromes: Focus on Molecular Mechanisms Underlying TRPM4 Channelopathies, Cardiovascular Therapeutics, 10.1155/2020/6615038, 2020, (1-10), Online publication date: 16-Dec-2020. Hof T, Chaigne S, Récalde A, Sallé L, Brette F and Guinamard R (2019) Transient receptor potential channels in cardiac health and disease, Nature Reviews Cardiology, 10.1038/s41569-018-0145-2, 16:6, (344-360), Online publication date: 1-Jun-2019. Gando I, Yang H and Coetzee W (2018) Functional significance of channelopathy gene variants in unexplained death, Forensic Science, Medicine and Pathology, 10.1007/s12024-018-0063-y, 15:3, (437-444), Online publication date: 1-Sep-2019. Gaur N, Hof T, Haissaguerre M and Vigmond E (2019) Propagation Failure by TRPM4 Overexpression, Biophysical Journal, 10.1016/j.bpj.2018.11.3137, 116:3, (469-476), Online publication date: 1-Feb-2019. 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Subbotina E, Williams N, Sampson B, Tang Y and Coetzee W (2018) Functional characterization of TRPM4 variants identified in sudden unexpected natural death, Forensic Science International, 10.1016/j.forsciint.2018.10.006, 293, (37-46), Online publication date: 1-Dec-2018. Ozhathil L, Rougier J, Arullampalam P, Essers M, Ross-Kaschitza D and Abriel H (2021) Deletion of Trpm4 Alters the Function of the Nav1.5 Channel in Murine Cardiac Myocytes, International Journal of Molecular Sciences, 10.3390/ijms22073401, 22:7, (3401) Brodehl A, Ebbinghaus H, Deutsch M, Gummert J, Gärtner A, Ratnavadivel S and Milting H (2019) Human Induced Pluripotent Stem-Cell-Derived Cardiomyocytes as Models for Genetic Cardiomyopathies, International Journal of Molecular Sciences, 10.3390/ijms20184381, 20:18, (4381) Dienes C, Kovács Z, Hézső T, Almássy J, Magyar J, Bányász T, Nánási P, Horváth B and Szentandrássy N (2021) Pharmacological Modulation and (Patho)Physiological Roles of TRPM4 Channel—Part 2: TRPM4 in Health and Disease, Pharmaceuticals, 10.3390/ph15010040, 15:1, (40) May 2018Vol 11, Issue 5 Advertisement Article InformationMetrics © 2018 American Heart Association, Inc.https://doi.org/10.1161/CIRCGEN.118.002103PMID: 29748318 Originally publishedJune 18, 2018 Keywordsgeneticsarrhythmias, cardiaccardiomyopathiesPDF download Advertisement SubjectsGenetics