Sodium Channelopathy Underlying Familial Sick Sinus Syndrome with Early Onset and Predominantly Male Characteristics Keisuke Abe, Taku Machida, Naokata Sumitomo, Hirokazu Yamamoto, Kimie Ohkubo, Ichiro Watanabe, Takeru Makiyama, Satoki Fukae, Masaki Kohno, Daniel T. Harrell, Taisuke Ishikawa, Yukiomi Tsuji, Akihiko Nogami, Taichi Watabe, Yasushi Oginosawa, Haruhiko Abe, Koji Maemura, Hideki Motomura and Naomasa Makita Circ Arrhythm Electrophysiol. published online April 24, 2014; Circulation: Arrhythmia and Electrophysiology is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 2014 American Heart Association, Inc. All rights reserved. Print ISSN: 1941-3149. Online ISSN: 1941-3084
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circep.ahajournals.org/content/early/2014/04/24/CIRCEP.113.001340
Data Supplement (unedited) at: http://circep.ahajournals.org/content/suppl/2014/04/24/CIRCEP.113.001340.DC1.html
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation: Arrhythmia and Electrophysiology can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answerdocument. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation: Arrhythmia and Electrophysiology is online at: http://circep.ahajournals.org//subscriptions/
Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
Sodium Channelopathy Underlying Familial Sick Sinus Syndrome with Early Onset and Predominantly Male Characteristics Running title: Abe et al.; Early-onset and male-predominant familial SSS
Keisuke Abe, MD1,10; Taku Machida, MD1; Naokata Sumitomo, MD2; Hirokazu Yamamoto, MD3; Kimie Ohkubo, MD4; Ichiro Watanabe, MD4; Takeru Makiyama, MD, PhD5; Satoki Fukae, MD6; Masaki Kohno, MD6; Daniel T. Harrell, BS1; Taisuke Ishikawa, DVM, PhD1; Yukiomi Tsuji, Tssuj uji, i MD, i, PhD1; Akihiko Nogami, MD7; Taichi Watabe, MD8; Yasushi Oginosawa, MD D8; Haruhiko Haru Ha ruhi ru hiko hi ko Abe, Abe be, MD9; Koji Maemura, Mae aemu mura mu r , MD, M , PhD6; Hideki MD Hid ki Motomura, Motomur M t ur ura, a MD3; Naomasa N a Makita, M Makit kita, MD, MD PhD1 1
Department n of nt of Molecular P Physiology, hyssio ology y, 3Departme Department m nt off Pediatrics, Pedi diatrics css, 6D cs, Department epaarttmennt off C Cardiovascular ardio ovaasccular M Medicine, ed d aki University aki Uni n versit itty G ity raaduaatee Sch hoo ool off Bio iome io meddical Sc me Scienc nces nc e ,N aga gas asaki k ; 2D Nagasaki Graduate School Biomedical Sciences, Nagasaki; Department epa parrt pa rtmeent n off Pediatrics, Pediiat atricc 4 Department a artment nt of of C Cardiovascular ard dio i vascullar Med Medicine, ed dici icine, Ni N Nihon hon University ho Uniiversiity G Graduate radduatte School ra S hool off M Sc Medicine, e ine, To edici T Tokyo; kyoo 5 Departmentt of Ca Card Cardiovascular rddio ova vasc sccullar a Me Medicine, edi dici cine ci ne,, Ky K Kyoto otoo Un ot Univ University iverssity iv t Gr ty Grad Graduate a ua ad u te S School choo ch ooll off Medicine, oo Medi Me dici di c ne ci n , Kyoto; Kyot Ky o o; 7Di ot Division D vii of h mM hythm anag an agem ag emen em entt, Yo en Yoko koha ko hama ha ma Rosai Ros o ai Hospital, os Hos o pitaal, Y okoh ok oham oh amaa; 8Th am Heart Rhythm Management, Yokohama Yokohama; Thee Second Seco Se co ond Department Dep par artm tm men nt off Internal Intee Medicine, 9D Department epartment t ntt off H Heart eartt Rh Rhyt Rhythm yth yt hm M hm Management, anag agem ag e ent, t, U University niiversi sity si ty off Oc O Occupational ccupa pati pa tionall and ti nd dE Environmental nviironmenttall H Health, takyushu; taky yushu;; 10Cu Kitakyushu; Current C rrentt Ad Addr Address: d ess: JJa Japanese apa p nese R Red ed dC Cross ross A Asahikawa sahi h kkaawa H hi Hospital, ospi pi pittaall,, A Asahikawa, sahi h ka hi k wa,, Japa Japan p n
Correspondence: Naomasa Makita, MD, PhD Department of Molecular Physiology Nagasaki University Graduate School of Biomedical Sciences 1-12-4 Sakamoto Nagasaki 852-8523 Japan Tel: +81-95-819-7031 Fax: +81-95-819-7911 E-mail: [email protected]
Journal Subject Code: [132] Arrhythmias - basic studies 1 Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
Abstract: Background – Sick sinus syndrome (SSS) is a common arrhythmia often associated with aging or organic heart diseases, but may also occur in a familial form with a variable mode of inheritance. Despite the identification of causative genes, including cardiac sodium channel (SCN5A), the etiology and molecular epidemiology of familial SSS remain undetermined primarily because of its rarity. Methods and Results – We genetically screened 48 members of 15 SSS families for mutations in several candidate genes, and determined the functional properties of mutant sodium (Na) channels using whole-cell patch clamping. We identified six SCN5A mutations includingg a compound heterozygous mutation. Heterologously expressed mutant Na channels showed cha hann nnel nn elss sh el show owed ow ed loss-of-function properties of reduced or no Na current density in conjunction with gating unctiion w itth ga gati ting ti n ng modulations. SCN5A n Among ns. Amon Am onng 19 19 ffamily amily members with SCN5 N5A N5 A mutations,, QT T prolongation prolongation and Brugada Bruu syndrome w associated four individuals, Agee of ons onset probands were erre associat ted e inn fo our aand nd ttwo wo in ndiv ividduaalss, respectively. iv resspec re e ti t vely ly Ag ly. A nset ns e iinn proban et p ob pr o an a carrying SCN5A CN5 CN5 N5A A mutations mutat ationss was at wass significantly sig gni nificaant n ly younger you ounngeer (12.4 ou (122.4 ± 4.66 years, y arrs,, n=5, ye n=5 =5 5, mean±SE) meean±S ±SE)) than thaa that of SCN5A-negative probands SSS negat attive pr rob o an nds ((47.0 47.0 .00 ± 4.6 ye yyears, ars, s, n=10; n=1 =10; =1 0 pA >A)) in in SC SCN5A SCN5 N5A A eexon on 21 21, pre previously iioo sll llinked inkkedd to DCM with conduction disorder (Figure 3).22 The mutation was identified in the brother (III:1) as well as in his asymptomatic father (II:1) and younger brother (III:7). Family A5: Sinus bradycardia and QT prolongation with day-to-day variation (QTc: 450–530 ms) were observed when the proband (II:2) was 22 years old, which were exacerbated after thyroidectomy as a treatment of hyperthyroidism at the age of 36. An electrophysiological study revealed SND (sinus node recovery time, 5.08 s), AV block (His ventricular, 68 ms), and atrial standstill in addition to QT prolongation (QTc=522 ms, Figure 2D), whereas the thyroid function was normally controlled. Her mother (I:2) and son (III:3) showed QT prolongation, while her brother (II:3) had both LQTS and BrS. Genetic screening revealed that the proband and these
7 Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
three family members carried an SCN5A missense mutation in exon 28, E1784K (c.5350C>A) (Figure 3), which is the most common SCN5A mutation in LQT3 associated with multiple clinical phenotypes of LQTS, BrS, and SSS.20 The proband prophylactically received an implantable cardioverter defibrillator at the age of 36, which discharged appropriately 1 year later during an episode of spontaneous ventricular fibrillation. Mutation analysis of probands and family members Nineteen mutation carriers were identified within the five families with SSS (A1–A5) (Supplemental Table S2). Seven individuals (37%) exhibited SSS, while ile seven carriers (37%) (37 37% were asymptomatic; other carriers showed variable arrhythmias including ding LQ LQTS LQTS, TS, BrS, TS BrS, Br S and and AFL SS,, suggesting sug ugge gest ge s in st i g that th SSS has a considerably considerabl blyy reduced bl reduced penetrance pene netran ne an nce in these families. No N without SSS, mutations were were identifiedd in HC HCN4 HCN4, N4,, KC N4 KCNQ1, CNQ N 1, KC KCNH2, CNH H2, KC KCNJ3, CNJ NJ33, MY M MYH6, H66, GJ GJA5, JA5, and a d IR an IRX3. IRX3 3. A Among m 22, 2, 23 A mut tat atio ionns we found, io foundd, D12 1275 12 75N 75 5 22 and ndd E E1784K 17784K 844K200 hhave avee pr previ previously iously ly bbeen een the SCN5A mutations D1275N
well-characterized; c ized; cteri d therefore, th heref effore, we analyzed anallyz y ed d the thhe functional functiional properties p opperti pr tiees off other o he ot h r mut mutants. tant ntss. nt Functionall characterization h t i ttii off SC SCN5A SCN5 N5A A mutations t ti As shown in Figure 4A, all plasmids, except for L1786fsX2, elicited a robust Na current but the non-inactivating late current, which characterizes type-3 LQTS mutations,24 was not evident. Peak current density measured 24 h after transfection was significantly reduced in MSN/S, M1880V+MSN/S, R219H, and L1786fsX2 compared with WT (Figure 4B, 4C). Because L1786fsX2 was non-functional, channel properties were further analyzed for M1880V+MSN/S and R219H (biophysical properties of other mutations are shown in Supplemental Table S3). The voltage-dependence of activation was significantly shifted in the depolarizing direction (+7.5 mV, p
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circep.ahajournals.org/content/early/2014/04/24/CIRCEP.113.001340
Data Supplement (unedited) at: http://circep.ahajournals.org/content/suppl/2014/04/24/CIRCEP.113.001340.DC1.html
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation: Arrhythmia and Electrophysiology can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answerdocument. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation: Arrhythmia and Electrophysiology is online at: http://circep.ahajournals.org//subscriptions/
Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
Sodium Channelopathy Underlying Familial Sick Sinus Syndrome with Early Onset and Predominantly Male Characteristics Running title: Abe et al.; Early-onset and male-predominant familial SSS
Keisuke Abe, MD1,10; Taku Machida, MD1; Naokata Sumitomo, MD2; Hirokazu Yamamoto, MD3; Kimie Ohkubo, MD4; Ichiro Watanabe, MD4; Takeru Makiyama, MD, PhD5; Satoki Fukae, MD6; Masaki Kohno, MD6; Daniel T. Harrell, BS1; Taisuke Ishikawa, DVM, PhD1; Yukiomi Tsuji, Tssuj uji, i MD, i, PhD1; Akihiko Nogami, MD7; Taichi Watabe, MD8; Yasushi Oginosawa, MD D8; Haruhiko Haru Ha ruhi ru hiko hi ko Abe, Abe be, MD9; Koji Maemura, Mae aemu mura mu r , MD, M , PhD6; Hideki MD Hid ki Motomura, Motomur M t ur ura, a MD3; Naomasa N a Makita, M Makit kita, MD, MD PhD1 1
Department n of nt of Molecular P Physiology, hyssio ology y, 3Departme Department m nt off Pediatrics, Pedi diatrics css, 6D cs, Department epaarttmennt off C Cardiovascular ardio ovaasccular M Medicine, ed d aki University aki Uni n versit itty G ity raaduaatee Sch hoo ool off Bio iome io meddical Sc me Scienc nces nc e ,N aga gas asaki k ; 2D Nagasaki Graduate School Biomedical Sciences, Nagasaki; Department epa parrt pa rtmeent n off Pediatrics, Pediiat atricc 4 Department a artment nt of of C Cardiovascular ard dio i vascullar Med Medicine, ed dici icine, Ni N Nihon hon University ho Uniiversiity G Graduate radduatte School ra S hool off M Sc Medicine, e ine, To edici T Tokyo; kyoo 5 Departmentt of Ca Card Cardiovascular rddio ova vasc sccullar a Me Medicine, edi dici cine ci ne,, Ky K Kyoto otoo Un ot Univ University iverssity iv t Gr ty Grad Graduate a ua ad u te S School choo ch ooll off Medicine, oo Medi Me dici di c ne ci n , Kyoto; Kyot Ky o o; 7Di ot Division D vii of h mM hythm anag an agem ag emen em entt, Yo en Yoko koha ko hama ha ma Rosai Ros o ai Hospital, os Hos o pitaal, Y okoh ok oham oh amaa; 8Th am Heart Rhythm Management, Yokohama Yokohama; Thee Second Seco Se co ond Department Dep par artm tm men nt off Internal Intee Medicine, 9D Department epartment t ntt off H Heart eartt Rh Rhyt Rhythm yth yt hm M hm Management, anag agem ag e ent, t, U University niiversi sity si ty off Oc O Occupational ccupa pati pa tionall and ti nd dE Environmental nviironmenttall H Health, takyushu; taky yushu;; 10Cu Kitakyushu; Current C rrentt Ad Addr Address: d ess: JJa Japanese apa p nese R Red ed dC Cross ross A Asahikawa sahi h kkaawa H hi Hospital, ospi pi pittaall,, A Asahikawa, sahi h ka hi k wa,, Japa Japan p n
Correspondence: Naomasa Makita, MD, PhD Department of Molecular Physiology Nagasaki University Graduate School of Biomedical Sciences 1-12-4 Sakamoto Nagasaki 852-8523 Japan Tel: +81-95-819-7031 Fax: +81-95-819-7911 E-mail: [email protected]
Journal Subject Code: [132] Arrhythmias - basic studies 1 Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
Abstract: Background – Sick sinus syndrome (SSS) is a common arrhythmia often associated with aging or organic heart diseases, but may also occur in a familial form with a variable mode of inheritance. Despite the identification of causative genes, including cardiac sodium channel (SCN5A), the etiology and molecular epidemiology of familial SSS remain undetermined primarily because of its rarity. Methods and Results – We genetically screened 48 members of 15 SSS families for mutations in several candidate genes, and determined the functional properties of mutant sodium (Na) channels using whole-cell patch clamping. We identified six SCN5A mutations includingg a compound heterozygous mutation. Heterologously expressed mutant Na channels showed cha hann nnel nn elss sh el show owed ow ed loss-of-function properties of reduced or no Na current density in conjunction with gating unctiion w itth ga gati ting ti n ng modulations. SCN5A n Among ns. Amon Am onng 19 19 ffamily amily members with SCN5 N5A N5 A mutations,, QT T prolongation prolongation and Brugada Bruu syndrome w associated four individuals, Agee of ons onset probands were erre associat ted e inn fo our aand nd ttwo wo in ndiv ividduaalss, respectively. iv resspec re e ti t vely ly Ag ly. A nset ns e iinn proban et p ob pr o an a carrying SCN5A CN5 CN5 N5A A mutations mutat ationss was at wass significantly sig gni nificaant n ly younger you ounngeer (12.4 ou (122.4 ± 4.66 years, y arrs,, n=5, ye n=5 =5 5, mean±SE) meean±S ±SE)) than thaa that of SCN5A-negative probands SSS negat attive pr rob o an nds ((47.0 47.0 .00 ± 4.6 ye yyears, ars, s, n=10; n=1 =10; =1 0 pA >A)) in in SC SCN5A SCN5 N5A A eexon on 21 21, pre previously iioo sll llinked inkkedd to DCM with conduction disorder (Figure 3).22 The mutation was identified in the brother (III:1) as well as in his asymptomatic father (II:1) and younger brother (III:7). Family A5: Sinus bradycardia and QT prolongation with day-to-day variation (QTc: 450–530 ms) were observed when the proband (II:2) was 22 years old, which were exacerbated after thyroidectomy as a treatment of hyperthyroidism at the age of 36. An electrophysiological study revealed SND (sinus node recovery time, 5.08 s), AV block (His ventricular, 68 ms), and atrial standstill in addition to QT prolongation (QTc=522 ms, Figure 2D), whereas the thyroid function was normally controlled. Her mother (I:2) and son (III:3) showed QT prolongation, while her brother (II:3) had both LQTS and BrS. Genetic screening revealed that the proband and these
7 Downloaded from http://circep.ahajournals.org/ at New York University/ Medical Center--New York on October 7, 2014
DOI: 10.1161/CIRCEP.113.001340
three family members carried an SCN5A missense mutation in exon 28, E1784K (c.5350C>A) (Figure 3), which is the most common SCN5A mutation in LQT3 associated with multiple clinical phenotypes of LQTS, BrS, and SSS.20 The proband prophylactically received an implantable cardioverter defibrillator at the age of 36, which discharged appropriately 1 year later during an episode of spontaneous ventricular fibrillation. Mutation analysis of probands and family members Nineteen mutation carriers were identified within the five families with SSS (A1–A5) (Supplemental Table S2). Seven individuals (37%) exhibited SSS, while ile seven carriers (37%) (37 37% were asymptomatic; other carriers showed variable arrhythmias including ding LQ LQTS LQTS, TS, BrS, TS BrS, Br S and and AFL SS,, suggesting sug ugge gest ge s in st i g that th SSS has a considerably considerabl blyy reduced bl reduced penetrance pene netran ne an nce in these families. No N without SSS, mutations were were identifiedd in HC HCN4 HCN4, N4,, KC N4 KCNQ1, CNQ N 1, KC KCNH2, CNH H2, KC KCNJ3, CNJ NJ33, MY M MYH6, H66, GJ GJA5, JA5, and a d IR an IRX3. IRX3 3. A Among m 22, 2, 23 A mut tat atio ionns we found, io foundd, D12 1275 12 75N 75 5 22 and ndd E E1784K 17784K 844K200 hhave avee pr previ previously iously ly bbeen een the SCN5A mutations D1275N
well-characterized; c ized; cteri d therefore, th heref effore, we analyzed anallyz y ed d the thhe functional functiional properties p opperti pr tiees off other o he ot h r mut mutants. tant ntss. nt Functionall characterization h t i ttii off SC SCN5A SCN5 N5A A mutations t ti As shown in Figure 4A, all plasmids, except for L1786fsX2, elicited a robust Na current but the non-inactivating late current, which characterizes type-3 LQTS mutations,24 was not evident. Peak current density measured 24 h after transfection was significantly reduced in MSN/S, M1880V+MSN/S, R219H, and L1786fsX2 compared with WT (Figure 4B, 4C). Because L1786fsX2 was non-functional, channel properties were further analyzed for M1880V+MSN/S and R219H (biophysical properties of other mutations are shown in Supplemental Table S3). The voltage-dependence of activation was significantly shifted in the depolarizing direction (+7.5 mV, p
