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  1. Association of a congenital long QT syndrome type 1 with Takotsubo cardiomyopathy.

    PubMed

    El-Battrawy, Ibrahim; Behnes, Michael; Borggrefe, Martin; Akin, Ibrahim

    2016-08-01

    The occurrence of takotsubo cardiomyopathy in a patient with congenital long QT syndrome has rarely been described. This case report discusses the occurrence of a clinically overt takotsubo cardiomyopathy accompanied by congenital long QT syndrome type 1 in a female patient. PMID:27525086

  2. How Is Long QT Syndrome Diagnosed?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Long QT Syndrome Diagnosed? Cardiologists diagnose and treat long ... or blood levels of potassium. Types of Inherited Long QT Syndrome If you have inherited LQTS, it ...

  3. Autonomic Control of Heart Rate and of QT Interval Variability Influences Arrhythmic Risk in Long QT Syndrome Type 1

    PubMed Central

    Porta, Alberto; Girardengo, Giulia; Bari, Vlasta; George, Alfred L.; Brink, Paul A.; Goosen, Althea; Crotti, Lia; Schwartz, Peter J.

    2014-01-01

    BACKGROUND A puzzling feature of the long QT syndrome (LQTS) is that family members carrying the same mutation often have divergent symptoms and clinical outcomes. OBJECTIVES We tested the hypothesis that vagal and sympathetic control, as assessed from spectral analysis of spontaneous beat-to-beat variability of RR and QT intervals from standard 24-hour electrocardiogram Holter recordings, can modulate the severity of LQTS type 1 (LQT1) in 46 members of a South-African LQT1 founder population carrying the clinically severe KCNQ1-A341V mutation. METHODS Nonmutation carriers (NMCs, n = 14) were compared with mutation carriers (MCs, n = 32), 22 with and 10 without major symptoms. We assessed the effect of circadian rhythm and of beta-blocker therapy over traditional time and frequency domain RR and QT variability indices. RESULTS The asymptomatic MCs differed significantly from the symptomatic MCs and from NMCs in less vagal control of heart rate and more reactive sympathetic modulation of the QT interval, particularly during daytime when arrhythmia risk for LQT1 patients is greatest. CONCLUSIONS The present data identify an additional factor contributing to the differential arrhythmic risk among LQT1 patients carrying the same mutation. A “normal” autonomic control confers a high risk, whereas patients with higher sympathetic control of the QT interval and reduced vagal control of heart rate are at lower risk. This differential “autonomic make-up,” likely under genetic control, will allow refinement of risk stratification within LQTS families, leading to more targeted management. PMID:25634836

  4. Refined multiscale entropy analysis of heart period and QT interval variabilities in long QT syndrome type-1 patients.

    PubMed

    Bari, Vlasta; Valencia, Jose F; Vallverdu, Montserrat; Girardengo, Giulia; Bassani, Tito; Marchi, Andrea; Calvillo, Laura; Caminal, Pere; Cerutti, Sergio; Brink, Paul A; Crotti, Lia; Schwartz, Peter J; Porta, Alberto

    2013-01-01

    This study assesses complexity of cardiovascular control in patients affected by type-1 variant of long QT (LQT1) syndrome. Complexity was assessed by refined multiscale entropy of heart period (HP) and QT interval variabilities. HP was taken as the time distance between two consecutive R peaks (RR) and QT interval was approximated as the time distance between the R-peak and T-wave apex (RTa) and between R-peak and T-wave end (RTe). RR, RTa and RTe intervals were automatically extracted from 24h Holter recordings and the daytime period was analyzed (from 02:00 to 06:00 PM). Non mutation carrier (NMC) individuals (n=11), utilized as a control group, were taken from the same family line of the mutation carrier (MC) subjects (n=26). We found that, while NMC and MC groups were indistinguishable based on time domain and complexity analyses of RR dynamics, complexity analysis of RTa and RTe variabilities clearly separates the two populations and suggests an impairment in the cardiac control mechanisms acting on the ventricles. PMID:24110995

  5. Response of the QT interval to mental and physical stress in types LQT1 and LQT2 of the long QT syndrome

    PubMed Central

    Paavonen, K; Swan, H; Piippo, K; Hokkanen, L; Laitinen, P; Viitasalo, M; Toivonen, L; Kontula, K

    2001-01-01

    OBJECTIVE—To study and compare the effects of mental and physical stress on long QT syndrome (LQTS) patients.
DESIGN—Case-control study.
MAIN OUTCOME MEASURES—QT intervals were measured from lead V3. Serum potassium and plasma catecholamine concentrations were also monitored.
PATIENTS—16 patients with type 1 LQTS (LQT1), 14 with type 2 LQTS (LQT2), both groups asymptomatic, and 14 healthy control subjects.
INTERVENTIONS—Three types of mental stress tests and a submaximal exercise stress test.
RESULTS—Heart rate responses to mental stress and exercise were similar in all groups. During mental stress, the mean QT interval shortened to a similar extent in controls (-29 ms), LQT1 patients (-34 ms), and LQT2 patients (-30 ms). During exercise, the corresponding QT adaptation to exercise stress was more pronounced (p < 0.01) in healthy controls (-47 ms) than in LQT1 (-38 ms) or LQT2 patients (-38 ms). During exercise changes in serum potassium concentrations were correlated to changes in QT intervals in controls, but not in LQTS patients. LQT1 and LQT2 patients did not differ in serum potassium, catecholamine or heart rate responses to mental or physical stress.
CONCLUSIONS—QT adaptation to mental and exercise stress in healthy people and in patients with LQTS is different. In healthy people QT adaptation is more sensitive to physical than to mental stress while no such diverging pattern was seen in asymptomatic LQTS patients.


Keywords: exercise; long QT syndrome; mental stress; potassium channel PMID:11410559

  6. Congenital long QT syndrome

    PubMed Central

    Crotti, Lia; Celano, Giuseppe; Dagradi, Federica; Schwartz, Peter J

    2008-01-01

    Congenital long QT syndrome (LQTS) is a hereditary cardiac disease characterized by a prolongation of the QT interval at basal ECG and by a high risk of life-threatening arrhythmias. Disease prevalence is estimated at close to 1 in 2,500 live births. The two cardinal manifestations of LQTS are syncopal episodes, that may lead to cardiac arrest and sudden cardiac death, and electrocardiographic abnormalities, including prolongation of the QT interval and T wave abnormalities. The genetic basis of the disease was identified in the mid-nineties and all the LQTS genes identified so far encode cardiac ion channel subunits or proteins involved in modulating ionic currents. Mutations in these genes (KCNQ1, KCNH2, KCNE1, KCNE2, CACNA1c, CAV3, SCN5A, SCN4B) cause the disease by prolonging the duration of the action potential. The most prevalent LQTS variant (LQT1) is caused by mutations in the KCNQ1 gene, with approximately half of the genotyped patients carrying KCNQ1 mutations. Given the characteristic features of LQTS, the typical cases present no diagnostic difficulties for physicians aware of the disease. However, borderline cases are more complex and require the evaluation of various electrocardiographic, clinical, and familial findings, as proposed in specific diagnostic criteria. Additionally, molecular screening is now part of the diagnostic process. Treatment should always begin with β-blockers, unless there are valid contraindications. If the patient has one more syncope despite a full dose β-blockade, left cardiac sympathetic denervation (LCSD) should be performed without hesitation and implantable cardioverter defibrillator (ICD) therapy should be considered with the final decision being based on the individual patient characteristics (age, sex, clinical history, genetic subgroup including mutation-specific features in some cases, presence of ECG signs – including 24-hour Holter recordings – indicating high electrical instability). The prognosis of the

  7. How Is Long QT Syndrome Treated?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Long QT Syndrome Treated? The goal of treating long QT syndrome (LQTS) is to prevent life-threatening, ... levels. (For more information, go to "What Causes Long QT Syndrome?" ) Many people who have LQTS also ...

  8. What Are the Signs and Symptoms of Long QT Syndrome?

    MedlinePlus

    ... Twitter. What Are the Signs and Symptoms of Long QT Syndrome? Major Signs and Symptoms If you ... This may cause noisy gasping while sleeping. Silent Long QT Syndrome Sometimes long QT syndrome doesn't ...

  9. A Neonate with Susceptibility to Long QT Syndrome Type 6 who Presented with Ventricular Fibrillation and Sudden Unexpected Infant Death

    PubMed Central

    Sauer, Charles W.; Marc-Aurele, Krishelle L.

    2016-01-01

    Patient: Female, 19-day Final Diagnosis: 19 day old neonate with susceptibility to Long QT syndrome • ventricular fibrillation Symptoms: Cardiac arrest • cardiac arrhythmia • encephalopathy Medication: — Clinical Procedure: Cardioversion Specialty: Pediatrics and Neonatology Objective: Rare disease Background: This is a case of a neonate with susceptibility to long QT syndrome (LQTS) who presented with a sudden unexpected infant death. Experts continue to debate whether universal electrocardiogram (ECG) screening of all newborns is feasible, practical, and cost-effective. Case Report: A 19-day-old neonate was found unresponsive by her mother. ECG showed ventricular fibrillation and a combination of a lidocaine drip plus multiple defibrillations converted the rhythm to normal sinus. Unfortunately, MRI brain imaging showed multiple infarcts and EEG showed burst suppression pattern with frequent seizures; life supportive treatment was stopped and the infant died. Genetic testing revealed two mutations in the KCNE2 gene consistent with susceptibility to LQTS type 6. Conclusions: We believe this case is the first to demonstrate both a precipitating electrocardiographic and genetic cause of death for an infant with LQTS, showing a cause-and-effect relationship between LQTS mutation, ventricular arrhythmia, and death. We wonder whether universal ECG newborn screening to prevent LQTS death could have saved this baby. PMID:27465075

  10. Autonomic modulation and antiarrhythmic therapy in a model of long QT syndrome type 3

    PubMed Central

    Fabritz, Larissa; Damke, Dierk; Emmerich, Markus; Kaufmann, Susann G.; Theis, Kathrin; Blana, Andreas; Fortmüller, Lisa; Laakmann, Sandra; Hermann, Sven; Aleynichenko, Elena; Steinfurt, Johannes; Volkery, Daniela; Riemann, Burkhard; Kirchhefer, Uwe; Franz, Michael R.; Breithardt, Günter; Carmeliet, Edward; Schäfers, Michael; Maier, Sebastian K.G.; Carmeliet, Peter; Kirchhof, Paulus

    2010-01-01

    Aims Clinical observations in patients with long QT syndrome carrying sodium channel mutations (LQT3) suggest that bradycardia caused by parasympathetic stimulation may provoke torsades de pointes (TdP). β-Adrenoceptor blockers appear less effective in LQT3 than in other forms of the disease. Methods and results We studied effects of autonomic modulation on arrhythmias in vivo and in vitro and quantified sympathetic innervation by autoradiography in heterozygous mice with a knock-in deletion (ΔKPQ) in the Scn5a gene coding for the cardiac sodium channel and increased late sodium current (LQT3 mice). Cholinergic stimulation by carbachol provoked bigemini and TdP in freely roaming LQT3 mice. No arrhythmias were provoked by physical stress, mental stress, isoproterenol, or atropine. In isolated, beating hearts, carbachol did not prolong action potentials per se, but caused bradycardia and rate-dependent action potential prolongation. The muscarinic inhibitor AFDX116 prevented effects of carbachol on heart rate and arrhythmias. β-Adrenoceptor stimulation suppressed arrhythmias, shortened rate-corrected action potential duration, increased rate, and minimized difference in late sodium current between genotypes. β-Adrenoceptor density was reduced in LQT3 hearts. Acute β-adrenoceptor blockade by esmolol, propranolol or chronic propranolol in vivo did not suppress arrhythmias. Chronic flecainide pre-treatment prevented arrhythmias (all P < 0.05). Conclusion Cholinergic stimulation provokes arrhythmias in this model of LQT3 by triggering bradycardia. β-Adrenoceptor density is reduced, and β-adrenoceptor blockade does not prevent arrhythmias. Sodium channel blockade and β-adrenoceptor stimulation suppress arrhythmias by shortening repolarization and minimizing difference in late sodium current. PMID:20110334

  11. Generation of human induced pluripotent stem cell line from a patient with a long QT syndrome type 2.

    PubMed

    Fatima, Azra; Ivanyuk, Dina; Herms, Stefan; Heilmann-Heimbach, Stefanie; O'Shea, Orla; Chapman, Charlotte; Izsvák, Zsuszanna; Farr, Martin; Hescheler, Jürgen; Šarić, Tomo

    2016-03-01

    We report here the generation of human iPS cell line UKKi009-A from dermal fibroblasts of a patient carrying heterozygous mutation c.3035-3045delTCCCTCGATGC, p.Leu1012Pro (fs*55) in KCNH2 gene leading to long QT syndrome type 2 (LQT2). We used the Sleeping Beauty transposon-based plasmids expressing OSKM along with microRNAs 307/367 to reprogram the fibroblasts. The iPS cells possess pluripotent stem cell characteristics and differentiate to cell lineages of all three germ layers. This cell line can serve as a source for in vitro modeling of LQT2. This cell line is distributed by the European Collection of Authenticated Cell Cultures (ECACC). PMID:27345990

  12. Genetics Home Reference: short QT syndrome

    MedlinePlus

    ... Information What information about a genetic condition can statistics provide? Why are some genetic conditions more common in particular ethnic groups? Genetic Changes Mutations in the KCNH2 , KCNJ2 , and KCNQ1 genes can cause short QT syndrome . These ...

  13. Short QT Syndrome in Current Clinical Practice.

    PubMed

    Khera, Sahil; Jacobson, Jason T

    2016-01-01

    Short QT syndrome is a rare inherited autosomal dominant cardiac channelopathy associated with malignant ventricular and atrial arrhythmias. A shortened corrected QT interval is a marker for risk of malignant arrhythmias, which are secondary to increased transmural dispersion of repolarization. The underlying gain of function mutations in the potassium channels are most common but genetic testing remains low yield. This review discusses the cellular mechanisms, genetic involvement, clinical presentation, and current recommended management of patients with short QT syndrome relevant to current clinical practice. PMID:26440650

  14. Large-scale mutational analysis of Kv11.1 reveals molecular insights into type 2 long QT syndrome

    NASA Astrophysics Data System (ADS)

    Anderson, Corey L.; Kuzmicki, Catherine E.; Childs, Ryan R.; Hintz, Caleb J.; Delisle, Brian P.; January, Craig T.

    2014-11-01

    It has been suggested that deficient protein trafficking to the cell membrane is the dominant mechanism associated with type 2 Long QT syndrome (LQT2) caused by Kv11.1 potassium channel missense mutations, and that for many mutations the trafficking defect can be corrected pharmacologically. However, this inference was based on expression of a small number of Kv11.1 mutations. We performed a comprehensive analysis of 167 LQT2-linked missense mutations in four Kv11.1 structural domains and found that deficient protein trafficking is the dominant mechanism for all domains except for the distal carboxy-terminus. Also, most pore mutations—in contrast to intracellular domain mutations—were found to have severe dominant-negative effects when co-expressed with wild-type subunits. Finally, pharmacological correction of the trafficking defect in homomeric mutant channels was possible for mutations within all structural domains. However, pharmacological correction is dramatically improved for pore mutants when co-expressed with wild-type subunits to form heteromeric channels.

  15. Large-scale Mutational Analysis of Kv11.1 Reveals Molecular Insights into Type 2 Long QT Syndrome

    PubMed Central

    Anderson, Corey L.; Kuzmicki, Catherine E.; Childs, Ryan R.; Hintz, Caleb J.; Delisle, Brian P.; January, Craig T.

    2014-01-01

    It has been suggested that deficient protein trafficking to the cell membrane is the dominant mechanism associated with type 2 Long QT syndrome (LQT2) caused by Kv11.1 potassium channel missense mutations, and that for many mutations the trafficking defect can be corrected pharmacologically. However, this inference was based on expression of a small number of Kv11.1 mutations. We performed a comprehensive analysis of 167 LQT2-linked missense mutations in four Kv11.1 structural domains and found that deficient protein trafficking is the dominant mechanism for all domains except for the distal C-terminus. Also, most pore mutations—in contrast to intracellular domain mutations —were found to have severe dominant-negative effects when co-expressed with wild type subunits. Finally, pharmacological correction of the trafficking defect in homomeric mutant channels was possible for mutations within all structural domains. However, pharmacological correction is dramatically improved for pore mutants when co-expressed with wild type subunits to form heteromeric channels. PMID:25417810

  16. A Neonate with Susceptibility to Long QT Syndrome Type 6 who Presented with Ventricular Fibrillation and Sudden Unexpected Infant Death.

    PubMed

    Sauer, Charles W; Marc-Aurele, Krishelle L

    2016-01-01

    BACKGROUND This is a case of a neonate with susceptibility to long QT syndrome (LQTS) who presented with a sudden unexpected infant death. Experts continue to debate whether universal electrocardiogram (ECG) screening of all newborns is feasible, practical, and cost-effective. CASE REPORT A 19-day-old neonate was found unresponsive by her mother. ECG showed ventricular fibrillation and a combination of a lidocaine drip plus multiple defibrillations converted the rhythm to normal sinus. Unfortunately, MRI brain imaging showed multiple infarcts and EEG showed burst suppression pattern with frequent seizures; life supportive treatment was stopped and the infant died. Genetic testing revealed two mutations in the KCNE2 gene consistent with susceptibility to LQTS type 6. CONCLUSIONS We believe this case is the first to demonstrate both a precipitating electrocardiographic and genetic cause of death for an infant with LQTS, showing a cause-and-effect relationship between LQTS mutation, ventricular arrhythmia, and death. We wonder whether universal ECG newborn screening to prevent LQTS death could have saved this baby. PMID:27465075

  17. Concealed long QT syndrome and intractable partial epilepsy: a case report.

    PubMed

    Anderson, Jason H; Bos, Johan Martijn; Meyer, Fredric B; Cascino, Gregory D; Ackerman, Michael J

    2012-11-01

    Herein, we describe a patient with concealed type 2 long QT syndrome with concomitant electroencephalogram-documented epilepsy. Although syncope in patients with long QT syndrome is common and often secondary to cerebral hypoxia after a protracted ventricular arrhythmia, this article demonstrates the importance of avoiding "tunnel vision" as patients with long QT syndrome could also have a primary seizure disorder. Identification of the etiology underlying seizurelike activity is paramount in instituting effective therapy. Furthermore, we theorize that abnormal KCHN2-encoded potassium channel repolarization in the brain could result in epilepsy and arrhythmias in long QT syndrome. PMID:23058853

  18. Association of the hERG mutation with long-QT syndrome type 2, syncope and epilepsy.

    PubMed

    Li, Guoliang; Shi, Rui; Wu, Jine; Han, Wenqi; Zhang, Aifeng; Cheng, Gong; Xue, Xiaolin; Sun, Chaofeng

    2016-03-01

    Mutations in the human ether‑à‑go‑go‑related gene (hERG) are responsible for long‑QT syndrome (LQTS) type 2 (LQT2). In the present study, a heterozygous missense mutation (A561V) linked to LQT2, syncope and epilepsy was identified in the S5/pore region of the hERG protein. The mutation, A561V, was prepared and subcloned into hERG‑pcDNA3.0. Mutant plasmids were co‑transfected into HEK‑293 cells, which stably express wild‑type (WT) hERG, in order to mimic a heterozygous genotype, and the whole‑cell current was recorded using a patch‑clamp technique. Confocal microscopy was performed to evaluate the membrane distribution of the hERG channel protein using a green fluorescent protein tagged to the N‑terminus of hERG. A561V‑hERG decreased the amplitude of the WT‑hERG currents in a concentration‑dependent manner. In addition, A561V‑hERG resulted in alterations to activation, inactivation and recovery from inactivation in the hERG protein channels. Further evaluation of hERG membrane localization indicated that the A561V‑hERG mutant protein was unable to travel to the plasma membrane, which resulted in a trafficking‑deficient WT‑hERG protein. In conclusion, A561V‑hERG exerts a potent dominant‑negative effect on WT‑hERG channels, resulting in decreased hERG currents and impairment of hERG membrane localization. This may partially elucidate the clinical manifestations of LQTS patients who carry the A561V mutation. PMID:26847485

  19. Association of the hERG mutation with long-QT syndrome type 2, syncope and epilepsy

    PubMed Central

    LI, GUOLIANG; SHI, RUI; WU, JINE; HAN, WENQI; ZHANG, AIFENG; CHENG, GONG; XUE, XIAOLIN; SUN, CHAOFENG

    2016-01-01

    Mutations in the human ether-à-go-go-related gene (hERG) are responsible for long-QT syndrome (LQTS) type 2 (LQT2). In the present study, a heterozygous missense mutation (A561V) linked to LQT2, syncope and epilepsy was identified in the S5/pore region of the hERG protein. The mutation, A561V, was prepared and subcloned into hERG-pcDNA3.0. Mutant plasmids were co-transfected into HEK-293 cells, which stably express wild-type (WT) hERG, in order to mimic a heterozygous genotype, and the whole-cell current was recorded using a patch-clamp technique. Confocal microscopy was performed to evaluate the membrane distribution of the hERG channel protein using a green fluorescent protein tagged to the N-terminus of hERG. A561V-hERG decreased the amplitude of the WT-hERG currents in a concentration-dependent manner. In addition, A561V-hERG resulted in alterations to activation, inactivation and recovery from inactivation in the hERG protein channels. Further evaluation of hERG membrane localization indicated that the A561V-hERG mutant protein was unable to travel to the plasma membrane, which resulted in a trafficking-deficient WT-hERG protein. In conclusion, A561V-hERG exerts a potent dominant-negative effect on WT-hERG channels, resulting in decreased hERG currents and impairment of hERG membrane localization. This may partially elucidate the clinical manifestations of LQTS patients who carry the A561V mutation. PMID:26847485

  20. The long Q-T syndromes.

    PubMed

    Gordon, N

    1994-01-01

    Loss of consciousness in childhood may be due to cardiovascular causes, and the Long Q-T syndromes can present with seizures. The Romano-Ward syndrome is of autosomal dominant inheritance, and the Jervell and Lange-Nielson syndrome, with associated deafness, of autosomal recessive inheritance. The diagnosis is often delayed, but a careful history can avoid this. The syndromes can appear to be due to an imbalance in the sympathetic nerve to the ventricular myocardium, and precipitating causes such as stress suggest a CNS influence on this. The electrocardiogram can confirm the prolonged Q-T interval, but this is not always present, at least without an exercise test. Treatment with beta-blockers is often successful. If a wrong diagnosis of epilepsy is made a chance may be missed of avoiding sudden death, quite apart from all the medical, and social consequences that can result from such a diagnosis. PMID:8048706

  1. Mouse models of long QT syndrome

    PubMed Central

    Salama, Guy; London, Barry

    2007-01-01

    Congenital long QT syndrome is a rare inherited condition characterized by prolongation of action potential duration (APD) in cardiac myocytes, prolongation of the QT interval on the surface electrocardiogram (ECG), and an increased risk of syncope and sudden death due to ventricular tachyarrhythmias. Mutations of cardiac ion channel genes that affect repolarization cause the majority of the congenital cases. Despite detailed characterizations of the mutated ion channels at the molecular level, a complete understanding of the mechanisms by which individual mutations may lead to arrhythmias and sudden death requires study of the intact heart and its modulation by the autonomic nervous system. Here, we will review studies of molecularly engineered mice with mutations in the genes (a) known to cause long QT syndrome in humans and (b) specific to cardiac repolarization in the mouse. Our goal is to provide the reader with a comprehensive overview of mouse models with long QT syndrome and to emphasize the advantages and limitations of these models. PMID:17038432

  2. KCNQ1 mutations associated with Jervell and Lange-Nielsen syndrome and autosomal recessive Romano-Ward syndrome in India-expanding the spectrum of long QT syndrome type 1.

    PubMed

    Vyas, Bijal; Puri, Ratna D; Namboodiri, Narayanan; Nair, Mohan; Sharma, Deepak; Movva, Sireesha; Saxena, Renu; Bohora, Shomu; Aggarwal, Neeraj; Vora, Amit; Kumar, Jatinder; Singh, Tarandeep; Verma, Ishwar C

    2016-06-01

    Long QT syndrome type 1 (LQT1) is the most common type of all Long QT syndromes (LQTS) and occurs due to mutations in KCNQ1. Biallelic mutations with deafness is called Jervell and Lange-Nielsen syndrome (JLNS) and without deafness is autosomal recessive Romano-Ward syndrome (AR RWS). In this prospective study, we report biallelic mutations in KCNQ1 in Indian patients with LQT1 syndrome. Forty patients with a clinical diagnosis of LQT1 syndrome were referred for molecular testing. Of these, 18 were excluded from the analysis as they did not fulfill the inclusion criteria of broad T wave ECG pattern of the study. Direct sequencing of KCNQ1 was performed in 22 unrelated probands, parents and at-risk family members. Mutations were identified in 17 patients, of which seven had heterozygous mutations and were excluded in this analysis. Biallelic mutations were identified in 10 patients. Five of 10 patients did not have deafness and were categorized as AR RWS, the rest being JLNS. Eight mutations identified in this study have not been reported in the literature and predicted to be pathogenic by in silico analysis. We hypothesize that the homozygous biallelic mutations identified in 67% of families was due to endogamous marriages in the absence of consanguinity. This study presents biallelic gene mutations in KCNQ1 in Asian Indian patients with AR JLNS and RWS. It adds to the scant worldwide literature of mutation studies in AR RWS. © 2016 Wiley Periodicals, Inc. PMID:27041150

  3. The binding site for channel blockers that rescue misprocessed human long QT syndrome type 2 ether-a-gogo-related gene (HERG) mutations.

    PubMed

    Ficker, Eckhard; Obejero-Paz, Carlos A; Zhao, Shuxia; Brown, Arthur M

    2002-02-15

    Mutations in the human ether-a-gogo-related gene (HERG) K(+) channel gene cause chromosome 7-linked long QT syndrome type 2 (LQT2), which is characterized by a prolonged QT interval in the electrocardiogram and an increased susceptibility to life-threatening cardiac arrhythmias. LQT2 mutations produce loss-of-function phenotypes and reduce I(Kr) currents either by the heteromeric assembly of non- or malfunctioning channel subunits with wild type subunits at the cell surface or by retention of misprocessed mutant HERG channels in the endoplasmic reticulum. Misprocessed mutations often encode for channel proteins that are functional upon incorporation into the plasma membrane. As a result the pharmacological correction of folding defects and restoration of protein function are of considerable interest. Here we report that the trafficking-deficient pore mutation HERG G601S was rescued by a series of HERG channel blockers that increased cell surface expression. Rescue by these pharmacological chaperones varied directly with their blocking potency. We used structure-activity relationships and site-directed mutagenesis to define the binding site of the pharmacological chaperones. We found that binding occurred in the inner cavity and correlated with hydrophobicity and cationic charge. Rescue was domain-restricted because the trafficking of two misprocessed mutations in the C terminus, HERG F805C and HERG R823W, was not restored by channel blockers. Our findings represent a first step toward the design of pharmacological chaperones that will rescue HERG K(+) channels without block. PMID:11741928

  4. Drug-Induced Long QT Syndrome

    PubMed Central

    Kannankeril, Prince; Darbar, Dawood

    2010-01-01

    The drug-induced long QT syndrome is a distinct clinical entity that has evolved from an electrophysiologic curiosity to a centerpiece in drug regulation and development. This evolution reflects an increasing recognition that a rare adverse drug effect can profoundly upset the balance between benefit and risk that goes into the prescription of a drug by an individual practitioner as well as the approval of a new drug entity by a regulatory agency. This review will outline how defining the central mechanism, block of the cardiac delayed-rectifier potassium current IKr, has contributed to defining risk in patients and in populations. Models for studying risk, and understanding the way in which clinical risk factors modulate cardiac repolarization at the molecular level are discussed. Finally, the role of genetic variants in modulating risk is described. PMID:21079043

  5. Structure of the Cyclic Nucleotide-Binding Homology Domain of the hERG Channel and Its Insight into Type 2 Long QT Syndrome.

    PubMed

    Li, Yan; Ng, Hui Qi; Li, Qingxin; Kang, CongBao

    2016-01-01

    The human ether-à-go-go related gene (hERG) channel is crucial for the cardiac action potential by contributing to the fast delayed-rectifier potassium current. Mutations in the hERG channel result in type 2 long QT syndrome (LQT2). The hERG channel contains a cyclic nucleotide-binding homology domain (CNBHD) and this domain is required for the channel gating though molecular interactions with the eag domain. Here we present solution structure of the CNBHD of the hERG channel. The structural study reveals that the CNBHD adopts a similar fold to other KCNH channels. It is self-liganded and it contains a short β-strand that blocks the nucleotide-binding pocket in the β-roll. Folding of LQT2-related mutations in this domain was shown to be affected by point mutation. Mutations in this domain can cause protein aggregation in E. coli cells or induce conformational changes. One mutant-R752W showed obvious chemical shift perturbation compared with the wild-type, but it still binds to the eag domain. The helix region from the N-terminal cap domain of the hERG channel showed unspecific interactions with the CNBHD. PMID:27025590

  6. Structure of the Cyclic Nucleotide-Binding Homology Domain of the hERG Channel and Its Insight into Type 2 Long QT Syndrome

    PubMed Central

    Li, Yan; Ng, Hui Qi; Li, Qingxin; Kang, CongBao

    2016-01-01

    The human ether-à-go-go related gene (hERG) channel is crucial for the cardiac action potential by contributing to the fast delayed-rectifier potassium current. Mutations in the hERG channel result in type 2 long QT syndrome (LQT2). The hERG channel contains a cyclic nucleotide-binding homology domain (CNBHD) and this domain is required for the channel gating though molecular interactions with the eag domain. Here we present solution structure of the CNBHD of the hERG channel. The structural study reveals that the CNBHD adopts a similar fold to other KCNH channels. It is self-liganded and it contains a short β-strand that blocks the nucleotide-binding pocket in the β-roll. Folding of LQT2-related mutations in this domain was shown to be affected by point mutation. Mutations in this domain can cause protein aggregation in E. coli cells or induce conformational changes. One mutant-R752W showed obvious chemical shift perturbation compared with the wild-type, but it still binds to the eag domain. The helix region from the N-terminal cap domain of the hERG channel showed unspecific interactions with the CNBHD. PMID:27025590

  7. Single-Channel Characteristics of Wild-Type IKs Channels and Channels formed with Two MinK Mutants that Cause Long QT Syndrome

    PubMed Central

    Sesti, Federico; Goldstein, Steve A.N.

    1998-01-01

    IKs channels are voltage dependent and K+ selective. They influence cardiac action potential duration through their contribution to myocyte repolarization. Assembled from minK and KvLQT1 subunits, IKs channels are notable for a heteromeric ion conduction pathway in which both subunit types contribute to pore formation. This study was undertaken to assess the effects of minK on pore function. We first characterized the properties of wild-type human IKs channels and channels formed only of KvLQT1 subunits. Channels were expressed in Xenopus laevis oocytes or Chinese hamster ovary cells and currents recorded in excised membrane patches or whole-cell mode. Unitary conductance estimates were dependent on bandwidth due to rapid channel “flicker.” At 25 kHz in symmetrical 100-mM KCl, the single-channel conductance of IKs channels was ∼16 pS (corresponding to ∼0.8 pA at 50 mV) as judged by noise-variance analysis; this was fourfold greater than the estimated conductance of homomeric KvLQT1 channels. Mutant IKs channels formed with D76N and S74L minK subunits are associated with long QT syndrome. When compared with wild type, mutant channels showed lower unitary currents and diminished open probabilities with only minor changes in ion permeabilities. Apparently, the mutations altered single-channel currents at a site in the pore distinct from the ion selectivity apparatus. Patients carrying these mutant minK genes are expected to manifest decreased K+ flux through IKs channels due to lowered single-channel conductance and altered gating. PMID:9834138

  8. A short story of the short QT syndrome.

    PubMed

    Maluli, Hayan Al; Meshkov, Arnold B

    2013-01-01

    Short QT syndrome is a recently recognized cause of cardiac rhythm disorders, including sudden cardiac death. Although the syndrome is rare, its potential lethality justifies routinely screening the electrocardiograms of patients with syncope or unexplained atrial or ventricular arrhythmias to look for this diagnosis. This review discusses recent advances in the understanding of the pathogenesis of this syndrome and outlines some of the challenges in establishing the diagnosis. PMID:23288944

  9. hERG quality control and the long QT syndrome.

    PubMed

    Foo, Brian; Williamson, Brittany; Young, Jason C; Lukacs, Gergely; Shrier, Alvin

    2016-05-01

    Long-QT syndrome type-2 (LQT2) is characterized by reduced functional expression of the human ether-à-go-go related (hERG) gene product, resulting in impaired cardiac repolarization and predisposition to fatal arrhythmia. Previous studies have implicated abnormal trafficking of misfolded hERG as the primary mechanism of LQT2, with misfolding being caused by mutations in the hERG gene (inherited) or drug treatment (acquired). More generally, environmental and metabolic stresses present a constant challenge to the folding of proteins, including hERG, and must be countered by robust protein quality control (QC) systems. Disposal of partially unfolded yet functional plasma membrane (PM) proteins by protein QC contributes to the loss-of-function phenotype in various conformational diseases including cystic fibrosis (CF) and long-QT syndrome type-2 (LQT2). The prevalent view has been that the loss of PM expression of hERG is attributed to biosynthetic block by endoplasmic reticulum (ER) QC pathways. However, there is a growing appreciation for protein QC pathways acting at post-ER cellular compartments, which may contribute to conformational disease pathogenesis. This article will provide a background on the structure and cellular trafficking of hERG as well as inherited and acquired LQT2. We will review previous work on hERG ER QC and introduce the more novel view that there is a significant peripheral QC at the PM and peripheral cellular compartments. Particular attention is drawn to the unique role of the peripheral QC system in acquired LQT2. Understanding the QC process and players may provide targets for therapeutic intervention in dealing with LQT2. PMID:26718903

  10. Effects of exercise on heart rate, QT, QTc and QT/QS2 in the Romano-Ward inherited long QT syndrome.

    PubMed

    Vincent, G M; Jaiswal, D; Timothy, K W

    1991-08-15

    Patients with the Romano-Ward inherited long QT syndrome have an incompletely defined cardiac sympathetic system abnormality, and exhibit ventricular arrhythmias during exercise, fear and anxiety. Treadmill and bicycle exercise were used to modulate cardiac autonomic activity in 27 Romano-Ward subjects and 27 normal controls. The heart rate, and the QT, QTc and QT/QS2 (ratio of electrical to mechanical systole) intervals were compared. Subjects with long QT were compared with normals. Those with a long QT interval had the following results: similar resting heart rates; lower rates during moderate (151.6 vs 169.6 beats/min, p = 0.04) and maximal (155.9 vs 182.1 beats/min, p = less than 0.001) exercise; an abnormal QT cycle-length relationship, with failure of the QT to shorten normally with increasing heart rate; an increase in QTc versus a decrease in normals; supine rest QT/QS2 ratio of 1.12 vs 0.93, p = 0.001; and an exercise QT/QS2 that increased by 30%, from 1.12 at rest to 1.45, versus 15%, in normals, from 0.93 to 1.07, p = 0.001. The lower heart rates and excessively prolonged QT/QS2 ratios during exercise further support an abnormality of, or abnormal cardiac response to, sympathetic activity. A QT/QS2 greater than 1.0 at rest, an exercise QT/QS2 ratio greater than 1.17, and an increase in QTc during moderate exercise may be helpful diagnostic findings in patients with borderline long QTc intervals at rest. PMID:1872278

  11. Short QT Syndrome – Review of Diagnosis and Treatment

    PubMed Central

    Schimpf, Rainer; Borggrefe, Martin

    2014-01-01

    Short QT syndrome (SQTS) is an inherited cardiac channelopathy characterised by an abnormally short QT interval and increased risk for atrial and ventricular arrhythmias. Diagnosis is based on the evaluation of symptoms (syncope or cardiac arrest), family history and electrocardiogram (ECG) findings. Mutations of cardiac ion channels responsible for the repolarisation orchestrate electrical heterogeneity during the action potential and provide substrate for triggering and maintaining of tachyarrhythmias. Due to the malignant natural history of SQTS, implantable cardioverter defibrillator (ICD) is the first-line therapy in affected patients. This review summarises current data and addresses the genetic basis and clinical features of SQTS. PMID:26835070

  12. Congenital and drug-induced long-QT syndrome: an update

    PubMed Central

    Wehrens, X.H.T.; Doevendans, P.A.

    2004-01-01

    The congenital long-QT syndrome is a potentially life-threatening condition characterised clinically by prolonged QT intervals, syncope and sudden cardiac death. The abnormally prolonged repolarisation is the result of mutations in genes encoding cardiac ion channels. The diagnosis of long-QT syndrome is based on clinical, electrocardiographic, and genetic criteria. Beta-blocking therapy is important in the treatment of long-QT syndrome, although pacemakers and implantable cardioverter defibrillators (ICD) are useful in certain categories of patients. In the near future, mutation-specific treatment will probably become a novel approach to this potentially lethal syndrome. Drug-induced long-QT syndrome has been associated with silent mutations and common polymorphisms in potassium and sodium channel genes associated with congenital long-QT syndrome. Genetic screening for such mutations and polymorphisms may become an important instrument in preventing drug-induced 'torsades de pointes' arrhythmias in otherwise asymptomatic patients. PMID:25696318

  13. Risk factors for drug-induced long-QT syndrome

    PubMed Central

    Paulussen, A.D.C.; Aerssens, J.

    2005-01-01

    Congenital long-QT syndrome (cLQTS) is a ventricular arrhythmia that is characterised by a prolonged QT interval on the surface electro-cardiogram (ECG). Clinical symptoms include sudden loss of consciousness (syncopes), seizures, cardiac arrest and sudden death. The prevalence of this inherited disease is approximately one in 10,000 in Caucasians. Over the last decade, more than 200 different diseases causing mutations have been identified in five genes that encode ion channels involved in the delicate balance of inward and outward K/Ca currents during the cardiac action potential. A prolonged QT interval accompanied by very similar clinical symptoms as in cLQTS can also occur in otherwise healthy individuals after the intake of specific drug(s). This phenomenon is known as 'acquired' or 'drug-induced' long-QT syndrome. Because the clinical symptoms of the two forms are very similar, the question arises whether a common underlying genetic basis also exists. Several studies indicate that only a minority (approximately 10%) of the drug-induced LQTS cases can be explained by a mutation or polymorphism in one of the known LQTS genes. Even though the disease can often at least partially be explained by environmental factors, mutations or polymorphisms in other genes are also expected to be involved, including genes encoding drug-metabolising enzymes, adrenergic receptors, hormone-related genes and mitochondrial genes. This article reviews the current knowledge on risk factors for drug-induced LQTS, with a special emphasis on the role of genetic determinants. ImagesFigure 1AFigure 2Figure 3 PMID:25696450

  14. Anaesthesia Application for Cardiac Denervation in a Patient with Long QT Syndrome and Cardiomyopathy

    PubMed Central

    Karadeniz, Ümit; Demir, Aslı; Koçulu, Rabia

    2016-01-01

    Long QT syndrome is a congenital disorder that is characterized by a prolongation of the QT interval on electrocardiograms and a propensity to ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest or sudden death. Cardiomyopathy and pulmonary hypertension diseases have additional risks in anaesthesia management. In this study, we emphasize on one lung ventilation, pacemaker-implantable cardioverter–defibrillator and the anaesthesia management process in a patient with long QT syndrome, cardiomyopathy and pulmonary hypertension who underwent thoracic sympathectomy. PMID:27366557

  15. Drugs to be avoided in patients with long QT syndrome: Focus on the anaesthesiological management

    PubMed Central

    Fazio, Giovanni; Vernuccio, Federica; Grutta, Giuseppe; Re, Giuseppe Lo

    2013-01-01

    Long QT syndrome incidence is increasing in general population. A careful pre-, peri- and post-operative management is needed for patients with this syndrome because of the risk of Torsades de Pointes and malignant arrhythmias. The available data regarding prevention of lethal Torsades de Pointes during anesthesia in patients with long QT syndrome is scant and conflicting: only case reports and small case series with different outcomes have been published. Actually, there are no definitive guidelines on pre-, peri- and post-operative anesthetic management of congenital long QT syndrome. Our review focuses on anesthetic recommendations for patients diagnosed with congenital long QT syndrome furnishing some key points for preoperative optimization, intraoperative anesthetic agents and postoperative care plan, which could be the best for patients with c-long QT syndrome who undergo surgery. PMID:23675554

  16. Toward Personalized Medicine: Using Cardiomyocytes Differentiated From Urine-Derived Pluripotent Stem Cells to Recapitulate Electrophysiological Characteristics of Type 2 Long QT Syndrome

    PubMed Central

    Jouni, Mariam; Si-Tayeb, Karim; Es-Salah-Lamoureux, Zeineb; Latypova, Xenia; Champon, Benoite; Caillaud, Amandine; Rungoat, Anais; Charpentier, Flavien; Loussouarn, Gildas; Baró, Isabelle; Zibara, Kazem; Lemarchand, Patricia; Gaborit, Nathalie

    2015-01-01

    Background Human genetically inherited cardiac diseases have been studied mainly in heterologous systems or animal models, independent of patients’ genetic backgrounds. Because sources of human cardiomyocytes (CMs) are extremely limited, the use of urine samples to generate induced pluripotent stem cell–derived CMs would be a noninvasive method to identify cardiac dysfunctions that lead to pathologies within patients’ specific genetic backgrounds. The objective was to validate the use of CMs differentiated from urine-derived human induced pluripotent stem (UhiPS) cells as a new cellular model for studying patients’ specific arrhythmia mechanisms. Methods and Results Cells obtained from urine samples of a patient with long QT syndrome who harbored the HERG A561P gene mutation and his asymptomatic noncarrier mother were reprogrammed using the episomal-based method. UhiPS cells were then differentiated into CMs using the matrix sandwich method. UhiPS-CMs showed proper expression of atrial and ventricular myofilament proteins and ion channels. They were electrically functional, with nodal-, atrial- and ventricular-like action potentials recorded using high-throughput optical and patch-clamp techniques. Comparison of HERG expression from the patient’s UhiPS-CMs to the mother’s UhiPS-CMs showed that the mutation led to a trafficking defect that resulted in reduced delayed rectifier K+ current (IKr). This phenotype gave rise to action potential prolongation and arrhythmias. Conclusions UhiPS cells from patients carrying ion channel mutations can be used as novel tools to differentiate functional CMs that recapitulate cardiac arrhythmia phenotypes. PMID:26330336

  17. Mechanisms of cardiac arrhythmias and sudden death in transgenic rabbits with long QT syndrome

    PubMed Central

    Brunner, Michael; Peng, Xuwen; Liu, Gong Xin; Ren, Xiao-Qin; Ziv, Ohad; Choi, Bum-Rak; Mathur, Rajesh; Hajjiri, Mohammed; Odening, Katja E.; Steinberg, Eric; Folco, Eduardo J.; Pringa, Ekatherini; Centracchio, Jason; Macharzina, Roland R.; Donahay, Tammy; Schofield, Lorraine; Rana, Naveed; Kirk, Malcolm; Mitchell, Gary F.; Poppas, Athena; Zehender, Manfred; Koren, Gideon

    2008-01-01

    Long QT syndrome (LQTS) is a heritable disease associated with ECG QT interval prolongation, ventricular tachycardia, and sudden cardiac death in young patients. Among genotyped individuals, mutations in genes encoding repolarizing K+ channels (LQT1:KCNQ1; LQT2:KCNH2) are present in approximately 90% of affected individuals. Expression of pore mutants of the human genes KCNQ1 (KvLQT1-Y315S) and KCNH2 (HERG-G628S) in the rabbit heart produced transgenic rabbits with a long QT phenotype. Prolongations of QT intervals and action potential durations were due to the elimination of IKs and IKr currents in cardiomyocytes. LQT2 rabbits showed a high incidence of spontaneous sudden cardiac death (>50% at 1 year) due to polymorphic ventricular tachycardia. Optical mapping revealed increased spatial dispersion of repolarization underlying the arrhythmias. Both transgenes caused downregulation of the remaining complementary IKr and IKs without affecting the steady state levels of the native polypeptides. Thus, the elimination of 1 repolarizing current was associated with downregulation of the reciprocal repolarizing current rather than with the compensatory upregulation observed previously in LQTS mouse models. This suggests that mutant KvLQT1 and HERG interacted with the reciprocal wild-type α subunits of rabbit ERG and KvLQT1, respectively. These results have implications for understanding the nature and heterogeneity of cardiac arrhythmias and sudden cardiac death. PMID:18464931

  18. Women, but not men, have prolonged QT interval if depressed after an acute coronary syndrome

    PubMed Central

    Whang, William; Julien, Howard M.; Higginbotham, Laura; Soto, Ana V.; Broodie, Nisha; Bigger, J. Thomas; Garan, Hasan; Burg, Matthew M.; Davidson, Karina W.

    2012-01-01

    Aims Depression is a mortality risk marker for acute coronary syndrome (ACS) patients. We hypothesized that the QT interval, a predictor for risk of sudden cardiac death, was related to depressive symptoms in ACS. Methods and results We performed an analysis of admission electrocardiograms from hospitalized patients with unstable angina or non-ST elevation myocardial infarction from two prospective observational studies of depression in ACS. Depressive symptoms were assessed with the Beck Depression Inventory (BDI), and depression was defined as BDI score ≥10, compared with <5. Patients with QRS duration ≥120 ms and/or who were prescribed antidepressants were excluded. QT intervals were adjusted for heart rate by two methods. Our analyses included 243 men (40.0% with BDI ≥10) and 139 women (62.0% with BDI ≥ 10). Among women, average QT corrected by Fridericia's method (QTcF) was 435.4 ± 26.6 ms in the depressed group, vs. 408.6 ± 24.3 ms in the non-depressed group (P< 0.01). However, among men, average QTcF was not significantly different between the depressed and non-depressed groups (415.4 ± 23.6 vs. 412.0 ± 25.8 ms, P= 0.29). In multivariable analyses that included hypertension, diabetes, ACS type, left ventricular ejection fraction <0.40, and use of QT-prolonging medication, there was a statistically significant interaction between depressive symptoms and gender (P< 0.001). Conclusions In this ACS sample, prolongation of the QT interval was associated with depressive symptoms in women, but not in men. Further investigation of the mechanism of the relationship between depression and abnormal cardiac repolarization, particularly in women, is warranted to develop treatment strategies. PMID:21798879

  19. Acquired long QT syndrome: a focus for the general pediatrician.

    PubMed

    Marzuillo, Pierluigi; Benettoni, Alessandra; Germani, Claudio; Ferrara, Giovanna; D'Agata, Biancamaria; Barbi, Egidio

    2014-04-01

    Acquired long QT syndrome (LQTS) is a disorder of cardiac repolarization most often due to specific drugs, hypokalemia, or hypomagnesemia that may precipitate torsade de pointes and cause sudden cardiac death. Common presentations of the LQTS are palpitations, presyncope, syncope, cardiac arrest, and seizures. An abnormal 12-lead electrocardiogram obtained while the patient is at rest is the key to diagnosis. The occurrence of drug-induced LQTS is unpredictable in any given individual, but a common observation is that most patients have at least 1 identifiable risk factor in addition to drug exposure. The cornerstone of the management of acquired LQTS includes the identification and discontinuation of any precipitating drug and the correction of metabolic abnormalities, such as hypokalemia or hypomagnesemia. Most of the episodes of torsade de pointes are short-lived and terminate spontaneously. We propose a management protocol that could be useful for the daily practice in the emergency pediatric department to reduce the risk of acquired QT prolongation. PMID:24694881

  20. Drug-induced long QT syndrome increases the risk of drowning.

    PubMed

    Vincenzi, Frank F

    2016-02-01

    There is strong evidence linking inherited long QT syndromes with an increased risk of drowning due to fatal arrhythmias in the water. Drug-induced long QT syndrome (DILQTS) is hypothesized to increase the risk of drowning by similar mechanisms. It is suggested that QT prolongation caused by a drug or drugs, when combined with the autonomic conflict associated with the mammalian dive reflex and/or the cold shock reflex, sets up conditions that may result in a sudden fatal arrhythmia while in water - thus an increased risk of drowning related to a drug-induced prolongation of the QT interval. Many widely used drugs prolong the QT interval thus raising a drug safety issue that needs confirmation or refutation. PMID:26826633

  1. A common antitussive drug, clobutinol, precipitates the long QT syndrome 2.

    PubMed

    Bellocq, Chloé; Wilders, Ronald; Schott, Jean-Jacques; Louérat-Oriou, Bénédicte; Boisseau, Pierre; Le Marec, Hervé; Escande, Denis; Baró, Isabelle

    2004-11-01

    QT prolongation, a classic risk factor for arrhythmias, can result from a mutation in one of the genes governing cardiac repolarization and also can result from the intake of a medication acting as blocker of the cardiac K(+) channel human ether-a-go-go-related gene (HERG). Here, we identified the arrhythmogenic potential of a nonopioid antitussive drug, clobutinol. The deleterious effects of clobutinol were suspected when a young boy, with a diagnosis of congenital long QT syndrome, experienced arrhythmias while being treated with this drug. Using the patch-clamp technique, we showed that clobutinol dose-dependently inhibited the HERG K(+) current with a half-maximum block concentration of 2.9 microM. In the proband, we identified a novel A561P HERG mutation. Two others long QT mutations (A561V and A561T) had been reported previously at the same position. None of the three mutants led to a sizeable current in heterologous expression system. When coexpressed with wild-type (WT) HERG channels, the three Ala561 mutants reduced the trafficking of WT and mutant heteromeric channels, resulting in decreased K(+) current amplitude (dominant-negative effects). In addition, A561P but not A561V and A561T mutants induced a approximately -11 mV shift of the current activation curve and accelerated deactivation, thereby partially counteracting the dominant-negative effects. A561P mutation and clobutinol effects on the human ventricular action potential characteristics were simulated using the Priebe-Beuckelmann model. Our work shows that clobutinol has limited effects on WT action potential but should be classified as a "drug to be avoided by congenital long QT patients" rather than as a "drug with risk of torsades de pointes". PMID:15280442

  2. [Progress in research on defective protein trafficking and functional restoration in HERG-associated long QT syndrome].

    PubMed

    Fang, Peiliang; Lian, Jiangfang

    2016-02-01

    The human ether-a-go-go related gene (HERG) encodes the α -subunit of the rapid component of the delayed rectifier K(+) channel, which is essential for the third repolarization of the action potential of human myocardial cells. Mutations of the HERG gene can cause type II hereditary long QT syndrome (LQT2), characterized by prolongation of the QT interval, abnormal T wave, torsade de pointes, syncope and sudden cardiac death. So far more than 300 HERG mutations have been identified, the majority of which can cause LQT2 due to HERG protein trafficking defect. It has been reported that certain drugs can induce acquired long QT syndrome through directly blocking the pore and/or affecting the HERG trafficking. The trafficking defects and K(+) currents can be restored with low temperature and certain drugs. However, the mechanisms underlying defective trafficking caused by HERG mutations and the inhibition/restoration of HERG trafficking by drugs are still unknown. This review summarizes the current understanding of the molecular mechanisms including HERG trafficking under physiological and pathological conditions, and the effects of drugs on the HERG trafficking, in order to provide theoretical evidence for the diagnosis and treatment of long QT syndrome. PMID:26829745

  3. Genotype–phenotype correlation in long QT syndrome families

    PubMed Central

    Qureshi, Sameera Fatima; Ali, Altaf; Venkateshwari, Ananthapur; Rao, Hygriv; Jayakrishnan, M.P.; Narasimhan, Calambur; Shenthar, Jayaprakash; Thangaraj, Kumarasamy; Nallari, Pratibha

    2015-01-01

    Heterogeneity in clinical manifestations is a well-known feature in Long QT Syndrome (LQTS). The extent of this phenomenon became evident in families wherein both symptomatic and asymptomatic family members are reported. The study hence warrants genetic testing and/or screening of family members of LQTS probands for risk stratification and prediction. Of the 46 families screened, 18 probands revealed novel variations/compound heterozygosity in the gene/s screened. Families 1–4 revealed probands carrying novel variations in KCNQ1 gene along with compound heterozygosity of risk genotypes of the SCN5A, KCNE1 and NPPA gene/s polymorphisms screened. It was also observed that families- 5, 6 and 7 were typical cases of “anticipation” in which both mother and child were diagnosed with congenital LQTS (cLQTS). Families- 16 and 17 represented aLQTS probands with variations in IKs and INa encoding genes. First degree relatives (FDRs) carrying the same haplotype as the proband were also identified which may help in predictive testing and management of LQTS. Most of the probands exhibiting a family history were found to be genetic compounds which clearly points to the role of cardiac genes and their modifiers in a recessive fashion in LQTS manifestation.

  4. Of Founder Populations, Long QT Syndrome, and Destiny

    PubMed Central

    Schwartz, Peter J.; Brink, Paul A.

    2009-01-01

    Founder populations, characterized by a single ancestor affected by LQTS and by a large number of individuals and families all related to the ancestor and thereby carrying the same disease-causing mutation, represent the ideal human model to study the role of “modifier genes” in the long QT syndrome (LQTS). This chapter reviews some of the fundamental concepts related to founder populations and provides the necessary historic background to understand why so many can be found in South Africa. The focus then moves onto a specific LQT1 founder population, carrier of the A341V mutation, that has been extensively studied during the last 10 years and has provided a significant number of previously unforeseen information. These novel findings range from an unusually high clinical severity not explained by the electrophysiological characteristics of the mutation, to the importance of the tonic and reflex control of heart rate for risk stratification, to the identification of the first modifier genes for the clinical severity of LQTS. PMID:19880070

  5. Long QT Syndrome: An Emerging Role for Inflammation and Immunity

    PubMed Central

    Lazzerini, Pietro Enea; Capecchi, Pier Leopoldo; Laghi-Pasini, Franco

    2015-01-01

    The long QT syndrome (LQTS), classified as congenital or acquired, is a multi-factorial disorder of myocardial repolarization predisposing to life-threatening ventricular arrhythmias, particularly torsades de pointes. In the latest years, inflammation and immunity have been increasingly recognized as novel factors crucially involved in modulating ventricular repolarization. In the present paper, we critically review the available information on this topic, also analyzing putative mechanisms and potential interplays with the other etiologic factors, either acquired or inherited. Accumulating data indicate inflammatory activation as a potential cause of acquired LQTS. The putative underlying mechanisms are complex but essentially cytokine-mediated, including both direct actions on cardiomyocyte ion channels expression and function, and indirect effects resulting from an increased central nervous system sympathetic drive on the heart. Autoimmunity represents another recently arising cause of acquired LQTS. Indeed, increasing evidence demonstrates that autoantibodies may affect myocardial electric properties by directly cross-reacting with the cardiomyocyte and interfering with specific ion currents as a result of molecular mimicry mechanisms. Intriguingly, recent data suggest that inflammation and immunity may be also involved in modulating the clinical expression of congenital forms of LQTS, possibly triggering or enhancing electrical instability in patients who already are genetically predisposed to arrhythmias. In this view, targeting immuno-inflammatory pathways may in the future represent an attractive therapeutic approach in a number of LQTS patients, thus opening new exciting avenues in antiarrhythmic therapy. PMID:26798623

  6. Evidence of genetic heterogeneity in the long QT syndrome

    SciTech Connect

    Keating, M. )

    1993-06-25

    thee long QT syndrome (LQT) is a familial predisposition to sudden death from cardiac arrhythmias. M. Keating et al. performed linkage analysis in a large Utah family and found that th disease was closely linked to the Harvey ras-1 (H-ras-1) locus on chromosome 11. With the use of the probe pTBB-2 at the H-ras-1 oncogene, a logarithm of the likelihood ratio for linkage (lod score) of +16.44 was obtained by Keating et al. In a subsequent study, tight linkage of LQT to the H-ras-1 locus was found in six other small LQT families. The combined lod score from these two studies was +21.65 at a recombination fraction of 0. This tight linkage suggests that mutations at the H-ras-1 locus or at a closely linked locus resulted in LQT in the families studied. In view of the clinical heterogeneity and possible genetic heterogeneity in this syndrome, we analyzed a large Jewish family with a history of LQT. This family, whose origin is the island of Jerba near Tunic and whose members reside in Israel, is probably the largest family with LQT outside the United States. It comprises 131 individuals, of whom 28 have been affected. Clinical and electrocardiographic data collected over 7 years were available for 92 family members and blood samples for genetic analysis were available for 74. This analysis, together with that of Keating et al., provides evidence for genetic heterogeneity in the determination of the LQT.

  7. In Utero Diagnosis of Long QT Syndrome by Magnetocardiography

    PubMed Central

    Cuneo, Bettina F.; Strasburger, Janette F.; Yu, Suhong; Horigome, Hitoshi; Hosono, Takayoshi; Kandori, Akihiko; Wakai, Ronald T.

    2013-01-01

    Background The electrophysiology of long QT syndrome (LQTS) in utero is virtually unstudied. Our goal here was to evaluate the efficacy of fetal magnetocardiography (fMCG) for diagnosis and prognosis of fetuses at risk of LQTS. Methods and Results We reviewed the pre/postnatal medical records of 30 fetuses referred for fMCG due to a family history of LQTS (n=17); neonatal/childhood sudden cardiac death (n=3) and/or presentation of prenatal LQTS rhythms (n=12): 2° AVB, ventricular tachycardia, heart rate < 3rd percentile. We evaluated heart rate and reactivity, cardiac time intervals, T-wave characteristics, and initiation/termination of Torsade de Pointes (TdP), and compared these with neonatal ECG findings. After birth, subjects were tested for LQTS mutations. Based on accepted clinical criteria, 21 subjects (70%; 9 KCNQ1, 5 KCNH2, 2 SCN5A, 2 other, 3 untested) had LQTS. Using a threshold of QTc= 490 ms, fMCG accurately identified LQTS fetuses with 89% (24/27) sensitivity and 89% (8/9) specificity in 36 sessions. Four fetuses (2 KCNH2 and 2 SCN5A), all with QTc ≥ 620 ms, had frequent episodes of TdP, which were present 22–79% of the time. While some episodes initiated with a long-short sequence, most initiations showed QRS aberrancy and a notable lack of pause dependency. T-wave alternans was strongly associated with severe LQTS phenotype. Conclusions QTc prolongation (≥490 ms) assessed by fMCG accurately identified LQTS in utero; extreme QTc prolongation (≥620 ms) predicted TdP. FMCG can play a critical role in the diagnosis and management of fetuses at risk of LQTS. PMID:24218437

  8. Quality of Life of Pediatric Patients With Long QT Syndrome.

    PubMed

    Czosek, Richard J; Kaltman, Jonathan R; Cassedy, Amy E; Shah, Maully J; Vetter, Victoria L; Tanel, Ronn E; Wernovksy, Gil; Wray, Jo; Marino, Bradley S

    2016-02-15

    Children with long QT syndrome (LQTS) live with the risk of sudden death, activity restrictions, and the need for daily medications. We sought to evaluate the quality of life (QOL), self-perception, and behavior of patients with LQTS as perceived by both patients and their parents and identify predictors of lower QOL. QOL (Pediatric QOL Inventory [PedsQL] and Pediatric Cardiac Quality of Life Inventory [PCQLI]), self-perception, and behavioral inventories were completed by patients with LQTS and their parents. Comparison of PedsQL scores was made to published data for healthy children using t tests, and PCQLI scores were compared with those of patients with differing complexity of congenital heart disease. Mixed modeling was used for multivariable analysis. Sixty-one patients with LQTS were evaluated (age 13.6 ± 3.0 years; male 49%). Compared with healthy children, the PedsQL Total, Psychosocial, and Physical Health Summary scores were significantly lower for patients with LQTS and parent proxy reports (p ≤0.001). In general, PCQLI scores of patients with LQTS and parents were similar to those of patients with tetralogy of Fallot (p ≥0.2), lower than those of patients with bicuspid aortic valve (p ≤0.02), and higher than those of patients with single ventricle (p ≤0.03). Lower patient and parent PCQLI scores were associated with internalizing problems. For parents, the presence of a cardiac device and medication side effects were additionally associated with lower PCQLI scores. In conclusion, patients with LQTS and their parents report lower QOL than normal children secondary to physical and psychosocial factors. Increasing focus on the psychological well-being of these patients is needed in an effort to improve their QOL. PMID:26721659

  9. The impact of recent advances in genetics in understanding disease mechanisms underlying the long QT syndromes.

    PubMed

    Harmer, Stephen C; Tinker, Andrew

    2016-07-01

    Long QT syndrome refers to a characteristic abnormality of the electrocardiogram and it is associated with a form of ventricular tachycardia known as torsade-de-pointes and sudden arrhythmic death. It can occur as part of a hereditary syndrome or can be acquired usually because of drug administration. Here we review recent genetic, molecular and cellular discoveries and outline how they have furthered our understanding of this disease. Specifically we focus on compound mutations, genome wide association studies of QT interval, modifier genes and the therapeutic implications of this recent work. PMID:26910742

  10. Sex differences in the mechanisms underlying long QT syndrome.

    PubMed

    Salama, Guy; Bett, Glenna C L

    2014-09-01

    Sexual dimorphism is a well-established phenomenon, but its degree varies tremendously among species. Since the early days of Einthoven's development of the three-lead galvanometer ECG, we have known there are marked differences in QT intervals of men and women. It required over a century to appreciate the profound implications of sex-based electrophysiological differences in QT interval on the panoply of sex differences with respect to arrhythmia risk, drug sensitivity, and treatment modalities. Little is known about the fundamental mechanism responsible for sex differences in electrical substrate of the human heart, in large part due to the lack of tissue availability. Animal models are an important research tool, but species differences in the sexual dimorphism of the QT interval, the ionic currents underlying the cardiac repolarization, and effects of sex steroids make it difficult to interpolate animal to human sex differences. In addition, in some species, different strains of the same animal model yield conflicting data. Each model has its strengths, such as ease of genetic manipulation in mice or size in dogs. However, many animals do not reproduce the sexual dimorphism of QT seen in humans. To match sex linked prolongation of QT interval and arrhythmogenic phenotype, the current data suggest that the rabbit may be best suited to provide insight into sex differences in humans. In the future, emerging technologies such as induced pluripotent stem cell derived cardiac myocyte systems may offer the opportunity to study sex differences in a controlled hormonal situation in the context of a sex specific human model system. PMID:24973386

  11. Effects of L-type Ca2+ channel antagonism on ventricular arrhythmogenesis in murine hearts containing a modification in the Scn5a gene modelling human long QT syndrome 3.

    PubMed

    Thomas, Glyn; Gurung, Iman S; Killeen, Matthew J; Hakim, Parvez; Goddard, Catharine A; Mahaut-Smith, Martyn P; Colledge, William H; Grace, Andrew A; Huang, Christopher L-H

    2007-01-01

    Ventricular arrhythmogenesis in long QT 3 syndrome (LQT3) involves both triggered activity and re-entrant excitation arising from delayed ventricular repolarization. Effects of specific L-type Ca2+ channel antagonism were explored in a gain-of-function murine LQT3 model produced by a DeltaKPQ 1505-1507 deletion in the SCN5A gene. Monophasic action potentials (MAPs) were recorded from epicardial and endocardial surfaces of intact, Langendorff-perfused Scn5a+/Delta hearts. In untreated Scn5a+/Delta hearts, epicardial action potential duration at 90% repolarization (APD90) was 60.0 +/- 0.9 ms compared with 46.9 +/- 1.6 ms in untreated wild-type (WT) hearts (P < 0.05; n = 5). The corresponding endocardial APD(90) values were 52.0 +/- 0.7 ms and 53.7 +/- 1.6 ms in Scn5a+/Delta and WT hearts, respectively (P > 0.05; n = 5). Epicardial early afterdepolarizations (EADs), often accompanied by spontaneous ventricular tachycardia (VT), occurred in 100% of MAPs from Scn5a+/Delta but not in any WT hearts (n = 10). However, EAD occurrence was reduced to 62 +/- 7.1%, 44 +/- 9.7%, 10 +/- 10% and 0% of MAPs following perfusion with 10 nm, 100 nm, 300 nm and 1 mum nifedipine, respectively (P < 0.05; n = 5), giving an effective IC50 concentration of 79.3 nm. Programmed electrical stimulation (PES) induced VT in all five Scn5a+/Delta hearts (n = 5) but not in any WT hearts (n = 5). However, repeat PES induced VT in 3, 2, 2 and 0 out of 5 Scn5a+/Delta hearts following perfusion with 10 nm, 100 nm, 300 nm and 1 mum nifedipine, respectively. Patch clamp studies in isolated ventricular myocytes from Scn5a+/Delta and WT hearts confirmed that nifedipine (300 nm) completely suppressed the inward Ca2+ current but had no effect on inward Na+ currents. No significant effects were seen on epicardial APD90, endocardial APD90 or ventricular effective refractory period in Scn5a+/Delta and WT hearts following perfusion with nifedipine at 1 nm, 10 nm, 100 nm, 300 nm and 1 microm nifedipine

  12. SCN4B-Encoded Sodium Channel β4 Subunit in Congenital Long-QT Syndrome

    PubMed Central

    Medeiros-Domingo, Argelia; Kaku, Toshihiko; Tester, David J.; Iturralde-Torres, Pedro; Itty, Ajit; Ye, Bin; Valdivia, Carmen; Ueda, Kazuo; Canizales-Quinteros, Samuel; Tusié-Luna, Maria Teresa; Makielski, Jonathan C.; Ackerman, Michael J.

    2012-01-01

    Background Congenital long-QT syndrome (LQTS) is potentially lethal secondary to malignant ventricular arrhythmias and is caused predominantly by mutations in genes that encode cardiac ion channels. Nearly 25% of patients remain without a genetic diagnosis, and genes that encode cardiac channel regulatory proteins represent attractive candidates. Voltage-gated sodium channels have a pore-forming α-subunit associated with 1 or more auxiliary β-subunits. Four different β-subunits have been described. All are detectable in cardiac tissue, but none have yet been linked to any heritable arrhythmia syndrome. Methods and Results We present a case of a 21-month-old Mexican-mestizo female with intermittent 2:1 atrioventricular block and a corrected QT interval of 712 ms. Comprehensive open reading frame/splice mutational analysis of the 9 established LQTS-susceptibility genes proved negative, and complete mutational analysis of the 4 Navβ-subunits revealed a L179F (C535T) missense mutation in SCN4B that cosegregated properly throughout a 3-generation pedigree and was absent in 800 reference alleles. After this discovery, SCN4B was analyzed in 262 genotype-negative LQTS patients (96% white), but no further mutations were found. L179F was engineered by site-directed mutagenesis and heterologously expressed in HEK293 cells that contained the stably expressed SCN5A-encoded sodium channel α-subunit (hNaV1.5). Compared with the wild-type, L179F-β4 caused an 8-fold (compared with SCN5A alone) and 3-fold (compared with SCN5A + WT-β4) increase in late sodium current consistent with the molecular/electrophysiological phenotype previously shown for LQTS-associated mutations. Conclusions We provide the seminal report of SCN4B-encoded Navβ4 as a novel LQT3-susceptibility gene. PMID:17592081

  13. Effects of cardioactive drugs on human induced pluripotent stem cell derived long QT syndrome cardiomyocytes.

    PubMed

    Kuusela, Jukka; Kujala, Ville J; Kiviaho, Anna; Ojala, Marisa; Swan, Heikki; Kontula, Kimmo; Aalto-Setälä, Katriina

    2016-01-01

    Human induced pluripotent stem cells (hiPSC) have enabled a major step forward in pathophysiologic studies of inherited diseases and may also prove to be valuable in in vitro drug testing. Long QT syndrome (LQTS), characterized by prolonged cardiac repolarization and risk of sudden death, may be inherited or result from adverse drug effects. Using a microelectrode array platform, we investigated the effects of six different drugs on the electrophysiological characteristics of human embryonic stem cell-derived cardiomyocytes as well as hiPSC-derived cardiomyocytes from control subjects and from patients with type 1 (LQT1) and type 2 (LQT2) of LQTS. At baseline the repolarization time was significantly longer in LQTS cells compared to controls. Isoprenaline increased the beating rate of all cell lines by 10-73 % but did not show any arrhythmic effects in any cell type. Different QT-interval prolonging drugs caused prolongation of cardiac repolarization by 3-13 % (cisapride), 10-20 % (erythromycin), 8-23 % (sotalol), 16-42 % (quinidine) and 12-27 % (E-4031), but we did not find any systematic differences in sensitivity between the control, LQT1 and LQT2 cell lines. Sotalol, quinidine and E-4031 also caused arrhythmic beats and beating arrests in some cases. In summary, the drug effects on these patient-specific cardiomyocytes appear to recapitulate clinical observations and provide further evidence that these cells can be applied for in vitro drug testing to probe their vulnerability to arrhythmia. PMID:27026928

  14. Safe drug use in long QT syndrome and Brugada syndrome: comparison of website statistics

    PubMed Central

    Postema, Pieter G.; Neville, Jon; de Jong, Jonas S.S.G.; Romero, Klaus; Wilde, Arthur A.M.; Woosley, Raymond L.

    2013-01-01

    Aims We sought to obtain insights into the efficacy of two websites, www.QTdrugs.org and www.BrugadaDrugs.org, that have the intention to prevent fatal arrhythmias due to unsafe drug use in Long QT syndrome and Brugada syndrome. Methods and results Prospective web-use statistical analysis combined with online surveys were employed. Our main outcome measure was the percentage of Long QT syndrome patients and Brugada syndrome patients reporting refraining or discontinuation of possible unsafe drugs. QTdrugs.org has received >3 100 000 visitors from 180 countries. Most visitors originated from the Americas (87%), as compared with Europe (7%), Asia (3%), Oceania (2%), and Africa (1%). The QTdrugs.org survey yielded 340 respondents: 34% were patients and 50% medical professionals. Of the patients, 79% reported that they refrained from, and 61% reported discontinuing drugs due to the website. The website was very much appreciated by 65% of the respondents and 30% found it rather helpful. The BrugadaDrugs.org received >48 000 visitors from 154 countries. Most visitors originated from Europe (46%) and the Americas (39%), but less from Asia (10%), Oceania (4%), and Africa (<1%). The BrugadaDrugs.org survey yielded 178 respondents: 68% were patients and 21% medical professionals. Of the patients, 72% reported refraining from, and 48% discontinuing drugs due to the website. The website was very much appreciated by 72% of the respondents and 25% found it rather helpful. Conclusion These websites are extensively used, they promote drug awareness, and they help patients to avoid possible pro-arrhythmic drugs. Visitors find the websites valuable but should note their limitations. PMID:23533266

  15. QT correction formulas and laboratory analysis on patients with metabolic syndrome and diabetes

    NASA Astrophysics Data System (ADS)

    Wong, Sara; Rivera, Pedro; Rodríguez, María. G.; Severeyn, Érika; Altuve, Miguel

    2013-11-01

    This article presents a study of ventricular repolarization in diabetic and metabolic syndrome subjects. The corrected QT interval (QTc) was estimated using four correction formulas commonly employed in the literature: Bazett, Fridericia, Framingham and Hodges. After extracting the Q, R and T waves from the electrocardiogram of 52 subjects (19 diabetic, 15 with metabolic syndrome and 18 control), using a wavelet-based approach, the RR interval and QT interval were determined. Then, QTc interval was computed using the formulas previously mentioned. Additionally, laboratory test (fasting glucose, cholesterol, triglycerides) were also evaluated. Results show that metabolic syndrome subjects have normal QTc. However, a longer QTc in this population may be a sign of future complication. The corrected QT interval by Fridericia's formula seems to be the most appropriated for metabolic syndrome subjects (low correlation coefficient between RR and QTc). Significant differences were obtained in the blood glucose and triglyceride levels, principally due to the abnormal sugar metabolization of metabolic syndrome and diabetic subjects. Further studies are focused on the acquisition of a larger database of metabolic syndrome and diabetics subjects and the repetition of this study using other populations, like high performance athletes.

  16. Reconstruction of action potential of repolarization in patients with congenital long-QT syndrome

    NASA Astrophysics Data System (ADS)

    Kandori, Akihiko; Shimizu, Wataru; Yokokawa, Miki; Kamakura, Shiro; Miyatake, Kunio; Murakami, Masahiro; Miyashita, Tsuyoshi; Ogata, Kuniomi; Tsukada, Keiji

    2004-05-01

    A method for reconstructing an action potential during the repolarization period was developed. This method uses a current distribution—plotted as a current-arrow map (CAM)—calculated using magnetocardiogram (MCG) signals. The current arrows are summarized during the QRS complex period and subtracted during the ST-T wave period in order to reconstruct the action-potential waveform. To ensure the similarity between a real action potential and the reconstructed action potential using CAM, a monophasic action potential (MAP) and an MCG of the same patient with type-I long-QT syndrome were measured. Although the MAP had one notch that was associated with early afterdepolarization (EAD), the reconstructed action potential had two large and small notches. The small notch timing agreed with the occurrence of the EAD in the MAP. On the other hand, the initiation time of an abnormal current distribution coincides with the appearance timing of the first large notch, and its end time coincides with that of the second small notch. These results suggest that a simple reconstruction method using a CAM based on MCG data can provide a similar action-potential waveform to a MAP waveform without having to introduce a catheter.

  17. Update on the Diagnosis and Management of Familial Long QT Syndrome.

    PubMed

    Waddell-Smith, Kathryn E; Skinner, Jonathan R

    2016-08-01

    This update was reviewed by the CSANZ Continuing Education and Recertification Committee and ratified by the CSANZ board in August 2015. Since the CSANZ 2011 guidelines, adjunctive clinical tests have proven useful in the diagnosis of LQTS and are discussed in this update. Understanding of the diagnostic and risk stratifying role of LQTS genetics is also discussed. At least 14 LQTS genes are now thought to be responsible for the disease. High-risk individuals may have multiple mutations, large gene rearrangements, C-loop mutations in KCNQ1, transmembrane mutations in KCNH2, or have certain gene modifiers present, particularly NOS1AP polymorphisms. In regards to treatment, nadolol is preferred, particularly for long QT type 2, and short acting metoprolol should not be used. Thoracoscopic left cardiac sympathectomy is valuable in those who cannot adhere to beta blocker therapy, particularly in long QT type 1. Indications for ICD therapies have been refined; and a primary indication for ICD in post-pubertal females with long QT type 2 and a very long QT interval is emerging. PMID:27262388

  18. Reduced Uptake of Family Screening in Genotype-Negative Versus Genotype-Positive Long QT Syndrome.

    PubMed

    Hanninen, Mikael; Klein, George J; Laksman, Zachary; Conacher, Susan S; Skanes, Allan C; Yee, Raymond; Gula, Lorne J; Leong-Sit, Peter; Manlucu, Jaimie; Krahn, Andrew D

    2015-08-01

    The acceptance and yield of family screening in genotype-negative long QT syndrome (LQTS) remains incompletely characterized. In this study of family screening for phenotype-definite Long QT Syndrome (LQTS, Schwartz score ≥3.5), probands at a regional Inherited Cardiac Arrhythmia clinic were reviewed. All LQTS patients were offered education by a qualified genetic counselor, along with materials for family screening including electronic and paper correspondence to provide to family members. Thirty-eight qualifying probands were identified and 20 of these had family members who participated in cascade screening. The acceptance of screening was found to be lower among families without a known pathogenic mutation (33 vs. 77 %, p = 0.02). A total of 52 relatives were screened; fewer relatives were screened per index case when the proband was genotype-negative (1.7 vs. 3.1, p = 0.02). The clinical yield of screening appeared to be similar irrespective of gene testing results (38 vs. 33 %, p = 0.69). Additional efforts to promote family screening among gene-negative long QT families may be warranted. PMID:25273952

  19. Genotype- and Phenotype-Guided Management of Congenital Long QT Syndrome

    PubMed Central

    Giudicessi, John R.; Ackerman, Michael J.

    2014-01-01

    Congenital Long QT syndrome (LQTS) is a genetically heterogeneous collection of heritable disorders of myocardial repolarization linked by their shared clinical phenotype of QT prolongation on electrocardiogram and an increased risk of potentially life-threatening cardiac arrhythmias. At the molecular level, mutations in 15 distinct LQTS-susceptibility genes that encode ion channel pore-forming α-subunits and accessory/auxiliary subunits central to the electromechanical function of the heart have been implicated in its pathogenesis. Over the past two decades, our evolving understanding of the electrophysiological mechanisms by which specific genetic substrates perturb the cardiac action potential has translated into vastly improved approaches to the diagnosis, risk stratification, and treatment of patients with LQTS. In this Review, we detail how our understanding of the molecular underpinnings of LQTS has yielded numerous clinically meaningful genotype-phenotype correlations and how these insights have translated into genotype- and phenotype-guided approaches to the clinical management of LQTS. PMID:24093767

  20. Sevoflurane-associated torsade de pointes in a patient with congenital long QT syndrome genotype 2.

    PubMed

    Kumakura, Mika; Hara, Koji; Sata, Takeyoshi

    2016-09-01

    Although patients with congenital long QT syndrome (c-LQTS) are considered to be at high risk for anesthesia, few reports describe c-LQTS genotype-specific considerations for anesthesia. We describe a case of torsade de pointes (TdP) caused by sevoflurane in a patient with c-LQTS genotype 2 (LQT2). A 39-year-old woman diagnosed with c-LQTS was scheduled for an elective therapeutic abortion. Immediately after starting the operation, the patient developed TdP. Since pulseless ventricular tachycardia was sustained despite intravenous injection of lidocaine, defibrillation was performed. Analysis of the electrocardiogram revealed that the corrected QT interval before anesthesia was 530 ms and 2.0% sevoflurane markedly prolonged the corrected QT interval to 693 ms. Postoperative studies revealed a mutation in the KCNH2 gene. Anesthesiologists should note that patients with LQT2 could be more susceptible to volatile anesthetics than are those with other major genotypes. Genotype-specific management of anesthesia may reduce the risk of developing TdP during the perioperative period. PMID:27555138

  1. Fluvoxamine by itself has potential to directly induce long QT syndrome at supra-therapeutic concentrations.

    PubMed

    Yamazaki-Hashimoto, Yukiko; Nakamura, Yuji; Ohara, Hiroshi; Cao, Xin; Kitahara, Ken; Izumi-Nakaseko, Hiroko; Ando, Kentaro; Yamazaki, Hiroshi; Ikeda, Takanori; Yamazaki, Junichi; Sugiyama, Atsushi

    2015-02-01

    Fluvoxamine is one of the typical selective serotonin-reuptake inhibitors. While its combined use with QT-prolonging drugs has been contraindicated because of the increase in plasma concentrations of such drugs, information is still limited whether fluvoxamine by itself may directly prolong the QT interval. We examined electropharmacological effects of fluvoxamine together with its pharmacokinetic profile by using the halothane-anesthetized dogs (n = 4). Fluvoxamine was intravenously administered in three escalating doses of 0.1, 1 and 10 mg/kg over 10 min with a pause of 20 min between the doses. The low dose provided therapeutic plasma drug concentration, whereas the middle and high doses attained approximately 10 and 100 times of the therapeutic ones, respectively. Supra-therapeutic concentration of fluvoxamine exerted the negative chronotropic, inotropic and hypotensive effects; and suppressed the atrioventricular nodal and intraventricular conductions, indicating inhibitory actions on Ca2+ and Na+ channels, whereas it delayed the repolarization in a reverse use-dependent manner, reflecting characteristics of rapidly activating delayed rectifier K+ current channel-blocking property. Fluvoxamine prolonged the terminal repolarization phase at 100 times higher concentration than the therapeutic, indicating its proarrhythmic potential. Thus, fluvoxamine by itself has potential to directly induce long QT syndrome at supra-therapeutic concentrations. PMID:25560394

  2. Reconstitution of defective protein trafficking rescues Long-QT syndrome in zebrafish.

    PubMed

    Meder, Benjamin; Scholz, Eberhard P; Hassel, David; Wolff, Christoph; Just, Steffen; Berger, Ina M; Patzel, Eva; Karle, Christoph; Katus, Hugo A; Rottbauer, Wolfgang

    2011-05-01

    Inherited cardiac arrhythmias are caused by genetic defects in ion channels and associated proteins. Mutations in these channels often do not affect their biophysical properties, but rather interfere with their trafficking to the cell membrane. Accordingly, strategies that could reroute the mutated channels to the membrane should be sufficient to restore the electrical properties of the affected cells, thereby suppressing the underlying arrhythmia. We identified here both, embryonic and adult zebrafish breakdance (bre) as a valuable model for human Long-QT syndrome. Electrocardiograms of adult homozygous bre mutants exhibit significant QT prolongation caused by delayed repolarization of the ventricle. We further show that the bre mutation (zERG(I59S)) disrupts ERG protein trafficking, thereby reducing the amount of active potassium channels on the cell membrane. Interestingly, improvement of channel trafficking by cisapride or dimethylsulfoxid is sufficient to reconstitute ERG channels on the cell membrane in a manner that suffices to suppress the Long-QT induced arrhythmia in breakdance mutant zebrafish. In summary, we show for the first time that therapeutic intervention can cure protein trafficking defects and the associated cardiac arrhythmia in vivo. PMID:21458413

  3. Electrophysiologic Substrate in Congenital Long QT Syndrome: Noninvasive Mapping with Electrocardiographic Imaging (ECGI)

    PubMed Central

    Desouza, Kavit A.; Abraham, Robert L.; Strom, Maria; Sacher, Frederic; Van Hare, George F.; Haïssaguerre, Michel; Roden, Dan M.; Rudy, Yoram

    2014-01-01

    Background Congenital Long QT syndrome (LQTS) is an arrhythmogenic disorder that causes syncope and sudden death. While its genetic basis has become well-understood, the mechanisms whereby mutations translate to arrhythmia susceptibility in the in situ human heart have not been fully defined. We used noninvasive ECG imaging (ECGI) to map the cardiac electrophysiologic substrate and examine whether LQTS patients display regional heterogeneities in repolarization, a substrate which promotes arrhythmogenesis. Methods and Results 25 subjects (9 LQT1, 9 LQT2, 5 LQT3 and 2 LQT5) with genotype and phenotype positive LQTS underwent ECGI. Seven normal subjects provided control. Epicardial maps of activation, recovery times (RT), Activation-recovery intervals (ARI) and repolarization dispersion were constructed. Activation was normal in all patients. However, RT and ARI were prolonged relative to control, indicating delayed repolarization and abnormally long APD (312 ± 30 ms vs. 235 ± 21 ms in control). ARI prolongation was spatially heterogeneous, with repolarization gradients much steeper than control (119 ± 19 ms/cm vs. 2.0 ± 2.0 ms/cm). There was variability in steepness and distribution of repolarization gradients between and within LQTS types. Repolarization gradients were steeper in symptomatic patients (130 ± 27 ms/cm in 12 symptomatic patients vs. 98 ± 19 ms/cm in 13 asymptomatic patients; P < 0.05). Conclusions LQTS patients display regions with steep repolarization dispersion caused by localized APD prolongation. This defines a substrate for reentrant arrhythmias, not detectable by surface ECG. Steeper dispersion in symptomatic patients suggests a possible role for ECGI in risk stratification. PMID:25294783

  4. Genetically induced dysfunctions of Kir2.1 channels: implications for short QT3 syndrome and autism–epilepsy phenotype

    PubMed Central

    Ambrosini, Elena; Sicca, Federico; Brignone, Maria S.; D'Adamo, Maria C.; Napolitano, Carlo; Servettini, Ilenio; Moro, Francesca; Ruan, Yanfei; Guglielmi, Luca; Pieroni, Stefania; Servillo, Giuseppe; Lanciotti, Angela; Valvo, Giulia; Catacuzzeno, Luigi; Franciolini, Fabio; Molinari, Paola; Marchese, Maria; Grottesi, Alessandro; Guerrini, Renzo; Santorelli, Filippo M.; Priori, Silvia; Pessia, Mauro

    2014-01-01

    Short QT3 syndrome (SQT3S) is a cardiac disorder characterized by a high risk of mortality and associated with mutations in Kir2.1 (KCNJ2) channels. The molecular mechanisms leading to channel dysfunction, cardiac rhythm disturbances and neurodevelopmental disorders, potentially associated with SQT3S, remain incompletely understood. Here, we report on monozygotic twins displaying a short QT interval on electrocardiogram recordings and autism–epilepsy phenotype. Genetic screening identified a novel KCNJ2 variant in Kir2.1 that (i) enhanced the channel's surface expression and stability at the plasma membrane, (ii) reduced protein ubiquitylation and degradation, (iii) altered protein compartmentalization in lipid rafts by targeting more channels to cholesterol-poor domains and (iv) reduced interactions with caveolin 2. Importantly, our study reveals novel physiological mechanisms concerning wild-type Kir2.1 channel processing by the cell, such as binding to both caveolin 1 and 2, protein degradation through the ubiquitin–proteasome pathway; in addition, it uncovers a potential multifunctional site that controls Kir2.1 surface expression, protein half-life and partitioning to lipid rafts. The reported mechanisms emerge as crucial also for proper astrocyte function, suggesting the need for a neuropsychiatric evaluation in patients with SQT3S and offering new opportunities for disease management. PMID:24794859

  5. Pharmacological approach to the treatment of long and short QT syndromes.

    PubMed

    Patel, Chinmay; Antzelevitch, Charles

    2008-04-01

    Inherited channelopathies have received increasing attention in recent years. The past decade has witnessed impressive progress in our understanding of the molecular and cellular basis of arrhythmogenesis associated with inherited channelopathies. An imbalance in ionic forces induced by these channelopathies affects the duration of ventricular repolarization and amplifies the intrinsic electrical heterogeneity of the myocardium, creating an arrhythmogenic milieu. Today, many of the channelopathies have been linked to mutations in specific genes encoding either components of ion channels or membrane or regulatory proteins. Many of the channelopathies are genetically heterogeneous with a variable degree of expression of the disease. Defining the molecular basis of channelopathies can have a profound impact on patient management, particularly in cases in which genotype-specific pharmacotherapy is available. The long QT syndrome (LQTS) is one of the first identified and most studied channelopathies where abnormal prolongation of ventricular repolarization predisposes an individual to life threatening ventricular arrhythmia called Torsade de Pointes. On the other hand of the spectrum, molecular defects favoring premature repolarization lead to Short QT syndrome (SQTS), a recently described inherited channelopathy. Both of these channelopathies are associated with a high risk of sudden cardiac death due to malignant ventricular arrhythmia. Whereas pharmacological therapy is first line treatment for LQTS, defibrillators are considered as primary treatment for SQTS. This review provides a comprehensive review of the molecular genetics, clinical features, genotype-phenotype correlations and genotype-specific approach to pharmacotherapy of these two mirror-image channelopathies, SQTS and LQTS. PMID:18378319

  6. Primary Carnitine Deficiency Presents Atypically with Long QT Syndrome: A Case Report.

    PubMed

    De Biase, Irene; Champaigne, Neena Lorenzana; Schroer, Richard; Pollard, Laura Malinda; Longo, Nicola; Wood, Tim

    2012-01-01

    Primary carnitine deficiency (PCD) is an autosomal recessive disorder of fatty acid oxidation caused by mutations in the SLC22A5 gene encoding for the carnitine transporter OCTN2. Carnitine uptake deficiency results in renal carnitine wasting and low plasma levels. PCD usually presents early in life either with acute metabolic crisis or as progressive cardiomyopathy that responds to carnitine supplementation. PCD inclusion in the newborn screening (NBS) programs has led to the identification of asymptomatic adult patients ascertained because of a positive NBS in their offspring. We extensively reviewed the literature and found that 15 of 42 adult published cases (35.7%) were symptomatic. Cardiac arrhythmias were present in five patients (12%). Here, we report the ascertainment and long-term follow-up of the first case of PCD presenting with long QT syndrome. The patient presented in her early twenties with a syncopal episode caused by ventricular tachycardia, and a prolonged QT interval. Arrhythmias were poorly controlled by pharmacologic therapy and a defibrillator was installed. Syncopal episodes escalated during her first pregnancy. A positive NBS in the patient's child suggested a carnitine uptake deficiency, which was confirmed by reduced carnitine transporter activity and by molecular testing. After starting carnitine supplementation, no further syncopal episodes have occurred and the QT interval returned to normal. As precaution, a low-dose metoprolol therapy and the defibrillator are still in place. Although rare, PCD should be ruled out as a cause of cardiac arrhythmias since oral carnitine supplementation is readily available and efficient. PMID:23430858

  7. An interdomain KCNH2 mutation produces an intermediate long QT syndrome

    PubMed Central

    Osterbur, Marika L.; Zheng, Renjian; Marion, Robert; Walsh, Christine; McDonald, Thomas V.

    2015-01-01

    Hereditary Long QT Syndrome is caused by deleterious mutation in one of several genetic loci, including locus LQT2 that contains the KCNH2 gene (or hERG), causing faulty cardiac repolarization. Here, we describe and characterize a novel mutation, p.Asp219Val in the hERG channel, identified in an 11 year old male with syncope and prolonged QT interval. Genetic sequencing showed a non-synonymous variation in KCNH2 (c.656A>T: amino acid p.Asp219Val). p.Asp219Val resides in a region of the channel predicted to be unstructured and flexible, located between the PAS (Per-Arnt-Sim) domain and its interaction sites in the transmembrane domain. The p.Asp219Val hERG channel produced K+ current that activated with modest changes in voltage dependence. Mutant channels were also slower to inactivate, recovered from inactivation more readily and demonstrated a significantly accelerated deactivation rate compared to the slow deactivation of WT channels. The intermediate nature of the biophysical perturbation is consistent with the degree of severity in the clinical phenotype. The findings of this study demonstrate a previously unknown role of the proximal N-terminus in deactivation and support the hypothesis that the proximal N-terminal domain is essential in maintaining slow hERG deactivation. PMID:25914329

  8. Short QT syndrome presenting as syncope: how short is too short?

    PubMed

    Portugal, Guilherme; Martins Oliveira, Mário; Silva Cunha, Pedro; Ferreira, Filipa; Lousinha, Ana; Fiarresga, António; Nogueira da Silva, Manuel; Cruz Ferreira, Rui

    2014-10-01

    We report the case of a 52-year-old man who presented to our emergency department (ED) after three episodes of syncope in the seven hours before admission. During his stay in the ED he had recurrent ventricular tachycardia (VT) requiring external electrical cardioversion. A 12-lead electrocardiogram (ECG) showed a short QT (SQT) interval (270 ms, QTc 327 ms), with frequent R-on-T extrasystoles triggering sustained polymorphic VT. After exclusion of other precipitating causes, the patient was diagnosed as having SQT syndrome (SQTS) according to the Gollob criteria. To our knowledge, this is the first known documentation of an SQT-caused arrhythmic episode on a 12-lead ECG, as well as the first reported case of SQTS in Portugal. The patient received an implantable cardioverter-defibrillator and was discharged. At a follow-up assessment 14 months later he was symptom-free, interrogation of the device showed no arrhythmic events, and the ECG showed a QT interval of 320 ms (QTc 347 ms). PMID:25442000

  9. We Only Find What We Look For: Fetal Heart Rate and the Diagnosis of Long QT Syndrome

    PubMed Central

    Cuneo, Bettina F.; Strasburger, Janette F.

    2015-01-01

    Long QT syndrome (LQTS), an inherited channelopathy, is a common cause of arrhythmic death in infants, children and young adults. Although many LQTS genes have been identified, most (~75%) of LQTS mutations are found in KCNQ1, KCNH2 or SCN5A. In most cases, treatment for LQTS is successful and modifies the risk of life-threatening arrhythmias; thus, making the correct diagnosis is important. The diagnosis of LQTS is made by the measurement of a prolonged QT interval on the standard ECG; family history or characteristic arrhythmia features are used to strengthen the diagnosis and genetic testing confirms the diagnosis. PMID:26286300

  10. Identification of Genetic Alterations, as Causative Genetic Defects in Long QT Syndrome, Using Next Generation Sequencing Technology

    PubMed Central

    Mademont-Soler, Irene; Allegue, Catarina; Cesar, Sergi; Ferrer-Costa, Carles; Coll, Monica; Mates, Jesus; Iglesias, Anna; Brugada, Josep; Brugada, Ramon

    2014-01-01

    Background Long QT Syndrome is an inherited channelopathy leading to sudden cardiac death due to ventricular arrhythmias. Despite that several genes have been associated with the disease, nearly 20% of cases remain without an identified genetic cause. Other genetic alterations such as copy number variations have been recently related to Long QT Syndrome. Our aim was to take advantage of current genetic technologies in a family affected by Long QT Syndrome in order to identify the cause of the disease. Methods Complete clinical evaluation was performed in all family members. In the index case, a Next Generation Sequencing custom-built panel, including 55 sudden cardiac death-related genes, was used both for detection of sequence and copy number variants. Next Generation Sequencing variants were confirmed by Sanger method. Copy number variations variants were confirmed by Multiplex Ligation dependent Probe Amplification method and at the mRNA level. Confirmed variants and copy number variations identified in the index case were also analyzed in relatives. Results In the index case, Next Generation Sequencing revealed a novel variant in TTN and a large deletion in KCNQ1, involving exons 7 and 8. Both variants were confirmed by alternative techniques. The mother and the brother of the index case were also affected by Long QT Syndrome, and family cosegregation was observed for the KCNQ1 deletion, but not for the TTN variant. Conclusions Next Generation Sequencing technology allows a comprehensive genetic analysis of arrhythmogenic diseases. We report a copy number variation identified using Next Generation Sequencing analysis in Long QT Syndrome. Clinical and familiar correlation is crucial to elucidate the role of genetic variants identified to distinguish the pathogenic ones from genetic noise. PMID:25494010

  11. Atrial Fibrillation and Long QT Syndrome Presenting in a 12-Year-Old Girl.

    PubMed

    Knoche, Jonathan W; Orland, Kate M; January, Craig T; Maginot, Kathleen R

    2012-01-01

    Atrial fibrillation (AF) is rare in the pediatric population; however, there is increasing recognition that AF can be inherited. Long QT syndrome (LQTS), likewise, can be both acquired and inherited with mutations leading to abnormalities in cardiac ion channel function. Mutations in KCNQ1 are the most common cause of LQTS. Although rare, mutations in KCNQ1 also can cause familial AF. This report describes a child with a KCNQ1 missense mutation who uniquely expresses concomitant AF and LQTS. Due to the potential for increased morbidity and mortality, young patients who present with AF and a family history suggestive of inherited arrhythmias should trigger further investigation for LQTS and subsequent familial genetic counseling. PMID:23193492

  12. Atrial Fibrillation and Long QT Syndrome Presenting in a 12-Year-Old Girl

    PubMed Central

    Knoche, Jonathan W.; Orland, Kate M.; January, Craig T.; Maginot, Kathleen R.

    2012-01-01

    Atrial fibrillation (AF) is rare in the pediatric population; however, there is increasing recognition that AF can be inherited. Long QT syndrome (LQTS), likewise, can be both acquired and inherited with mutations leading to abnormalities in cardiac ion channel function. Mutations in KCNQ1 are the most common cause of LQTS. Although rare, mutations in KCNQ1 also can cause familial AF. This report describes a child with a KCNQ1 missense mutation who uniquely expresses concomitant AF and LQTS. Due to the potential for increased morbidity and mortality, young patients who present with AF and a family history suggestive of inherited arrhythmias should trigger further investigation for LQTS and subsequent familial genetic counseling. PMID:23193492

  13. α1-Syntrophin Variant Identified in Drug-Induced Long QT Syndrome Increases Late Sodium Current

    PubMed Central

    Choi, Jong-Il; Wang, Chaojian; Thomas, Matthew J.; Pitt, Geoffrey S.

    2016-01-01

    Drug-induced long-QT syndrome (diLQTS) is often due to drug block of IKr, especially in genetically susceptible patients with subclinical mutations in the IKr-encoding KCHN2. Few variants in the cardiac NaV1.5 Na+ channel complex have been associated with diLQTS. We tested whether a novel SNTA1 (α1-syntrophin) variant (p.E409Q) found in a patient with diLQTS increases late sodium current (INa-L), thereby providing a disease mechanism. Electrophysiological studies were performed in HEK293T cells co-expressing human NaV1.5/nNOS/PMCA4b with either wild type (WT) or SNTA1 variants (A390V-previously reported in congenital LQTS; and E409Q); and in adult rat ventricular cardiomyocytes infected with SNTA1 expressing adenoviruses (WT or one of the two SNTA1 variants). In HEK293T cells and in cardiomyocytes, there was no significant difference in the peak INa densities among the SNTA1 WT and variants. However, both variants increased INa-L (% of peak current) in HEK293T cells (0.58±0.10 in WT vs. 0.90±0.11 in A390V, p = 0.048; vs. 0.88±0.07 in E409Q, p = 0.023). In cardiomyocytes, INa-L was significantly increased by E409Q, but not by A390V compared to WT (0.49±0.14 in WT vs.0.94±0.23 in A390V, p = 0.099; vs. 1.12±0.24 in E409Q, p = 0.019). We demonstrated that a novel SNTA1 variant is likely causative for diLQTS by augmenting INa-L. These data suggest that variants within the NaV1.5-interacting α1-syntrophin are a potential mechanism for diLQTS, thereby expanding the concept that variants within congenital LQTS loci can cause diLQTS. PMID:27028743

  14. Malignant Perinatal Variant of Long-QT Syndrome Caused by a Profoundly Dysfunctional Cardiac Sodium Channel

    PubMed Central

    Wang, Dao W.; Crotti, Lia; Shimizu, Wataru; Pedrazzini, Matteo; Cantu', Francesco; De Filippo, Paolo; Kishiki, Kanako; Miyazaki, Aya; Ikeda, Tomoaki; Schwartz, Peter J.; George, Alfred L.

    2009-01-01

    Background Inherited cardiac arrhythmia susceptibility contributes to sudden death during infancy and may contribute to perinatal and neonatal mortality, but the molecular basis of this risk and the relationship to genetic disorders presenting later in life is unclear. We studied the functional and pharmacological properties of a novel de novo cardiac sodium channel gene (SCN5A) mutation associated with an extremely severe perinatal presentation of long-QT syndrome in unrelated probands of different ethnicity. Methods and Results Two subjects exhibiting severe fetal and perinatal ventricular arrhythmias were screened for SCN5A mutations and the functional properties of a novel missense mutation (G1631D) were determined by whole-cell patch clamp recording. In vitro electrophysiological studies revealed a profound defect in sodium channel function characterized by ~10-fold slowing of inactivation, increased persistent current, slowing of recovery from inactivation, depolarized voltage dependence of activation and inactivation. Single channel recordings demonstrated increased frequency of late openings, prolonged mean open time and increased latency to first opening for the mutant. Subjects carrying this mutation responded clinically to the combination of mexiletine with propranolol and survived. Pharmacologically, the mutant exhibited 2-fold greater tonic and use-dependent mexiletine block than wildtype channels. The mutant also exhibited enhanced tonic (2.4-fold) and use-dependent block (~5-fold) by propranolol, and we observed additive effects of the two drugs on the mutant. Conclusions Our study demonstrates the molecular basis for a malignant perinatal presentation of long-QT syndrome, illustrates novel functional and pharmacological properties of SCN5A-G1631D which caused the disorder, and reveals therapeutic benefits of propranolol block of mutant sodium channels in this setting. PMID:19808432

  15. In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome.

    PubMed

    Romero, Lucia; Trenor, Beatriz; Yang, Pei-Chi; Saiz, Javier; Clancy, Colleen E

    2015-10-01

    Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired long-QT syndrome (aLQTS). We developed a computational approach to reveal the pharmacological properties of I(Kr) blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in I(Kr) channel gating that would be expected to result from benign genetic variants.Weused themodel to predict themost potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect. We systematically performed “in silico mutagenesis” by altering discrete kinetic transition rates of the Fink et al. Markov model of human I(Kr) channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of I(Kr) channels. We then screened and identified the properties of I(Kr) blockers that caused acquired long QT and therefore unmasked mutant phenotypes formild,moderate and severe variants. Mutant I(Kr) channels were incorporated into the O'Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of I(Kr)-drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and I(Kr) mutated cells. Our results show that drugs with disparate affinities to conformation states of the I(Kr) channel are key to amplify variants underlying susceptibility to acquired long QT syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a

  16. In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome

    PubMed Central

    Romero, Lucia; Trenor, Beatriz; Yang, Pei-Chi; Saiz, Javier; Clancy, Colleen E.

    2016-01-01

    Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired long-QT syndrome (aLQTS). We developed a computational approach to reveal the pharmacological properties of IKr blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in IKr channel gating that would be expected to result from benign genetic variants. We used the model to predict the most potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect. We systematically performed “in silico mutagenesis” by altering discrete kinetic transition rates of the Fink et al. Markov model of human IKr channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of IKr channels. We then screened and identified the properties of IKr blockers that caused acquired long QT and therefore unmasked mutant phenotypes for mild, moderate and severe variants. Mutant IKr channels were incorporated into the O'Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of IKr–drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and IKr mutated cells. Our results show that drugs with disparate affinities to conformation states of the IKr channel are key to amplify variants underlying susceptibility to acquired long QT syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a mathematical

  17. In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome

    PubMed Central

    Romero, Lucia; Trenor, Beatriz; Yang, Pei-Chi; Saiz, Javier; Clancy, Colleen E.

    2014-01-01

    Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired Long-QT Syndrome (aLTQS). We developed a computational approach to reveal the pharmacological properties of IKr blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in IKr channel gating that would be expected to result from benign genetic variants. We used the model to predict the most potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect. We systematically performed “in silico mutagenesis” by altering discrete kinetic transition rates of the Fink et al. Markov model of human IKr channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of IKr channels. We then screened and identified the properties of IKr blockers that caused acquired Long QT and therefore unmasked mutant phenotypes for mild, moderate and severe variants. Mutant IKr channels were incorporated into the O’Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of IKr-drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and IKr mutated cells. Our results show that drugs with disparate affinities to conformation states of the IKr channel are key to amplify variants underlying susceptibility to acquired Long QT Syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a mathematical

  18. In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome.

    PubMed

    Romero, Lucia; Trenor, Beatriz; Yang, Pei-Chi; Saiz, Javier; Clancy, Colleen E

    2014-07-01

    Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired long-QT syndrome (aLQTS). We developed a computational approach to reveal the pharmacological properties of IKr blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in IKr channel gating that would be expected to result from benign genetic variants. We used the model to predict the most potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect. We systematically performed "in silico mutagenesis" by altering discrete kinetic transition rates of the Fink et al. Markov model of human IKr channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of IKr channels. We then screened and identified the properties of IKr blockers that caused acquired long QT and therefore unmasked mutant phenotypes for mild, moderate and severe variants. Mutant IKr channels were incorporated into the O'Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of IKr-drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and IKr mutated cells. Our results show that drugs with disparate affinities to conformation states of the IKr channel are key to amplify variants underlying susceptibility to acquired long QT syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a mathematical

  19. Genetic analysis, in silico prediction, and family segregation in long QT syndrome.

    PubMed

    Riuró, Helena; Campuzano, Oscar; Berne, Paola; Arbelo, Elena; Iglesias, Anna; Pérez-Serra, Alexandra; Coll-Vidal, Mònica; Partemi, Sara; Mademont-Soler, Irene; Picó, Ferran; Allegue, Catarina; Oliva, Antonio; Gerstenfeld, Edward; Sarquella-Brugada, Georgia; Castro-Urda, Víctor; Fernández-Lozano, Ignacio; Mont, Lluís; Brugada, Josep; Scornik, Fabiana S; Brugada, Ramon

    2015-01-01

    The heritable cardiovascular disorder long QT syndrome (LQTS), characterized by prolongation of the QT interval on electrocardiogram, carries a high risk of sudden cardiac death. We sought to add new data to the existing knowledge of genetic mutations contributing to LQTS to both expand our understanding of its genetic basis and assess the value of genetic testing in clinical decision-making. Direct sequencing of the five major contributing genes, KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2, was performed in a cohort of 115 non-related LQTS patients. Pathogenicity of the variants was analyzed using family segregation, allele frequency from public databases, conservation analysis, and Condel and Provean in silico predictors. Phenotype-genotype correlations were analyzed statistically. Sequencing identified 36 previously described and 18 novel mutations. In 51.3% of the index cases, mutations were found, mostly in KCNQ1, KCNH2, and SCN5A; 5.2% of cases had multiple mutations. Pathogenicity analysis revealed 39 mutations as likely pathogenic, 12 as VUS, and 3 as non-pathogenic. Clinical analysis revealed that 75.6% of patients with QTc≥500 ms were genetically confirmed. Our results support the use of genetic testing of KCNQ1, KCNH2, and SCN5A as part of the diagnosis of LQTS and to help identify relatives at risk of SCD. Further, the genetic tools appear more valuable as disease severity increases. However, the identification of genetic variations in the clinical investigation of single patients using bioinformatic tools can produce erroneous conclusions regarding pathogenicity. Therefore segregation studies are key to determining causality. PMID:24667783

  20. Genetic analysis, in silico prediction, and family segregation in long QT syndrome

    PubMed Central

    Riuró, Helena; Campuzano, Oscar; Berne, Paola; Arbelo, Elena; Iglesias, Anna; Pérez-Serra, Alexandra; Coll-Vidal, Mònica; Partemi, Sara; Mademont-Soler, Irene; Picó, Ferran; Allegue, Catarina; Oliva, Antonio; Gerstenfeld, Edward; Sarquella-Brugada, Georgia; Castro-Urda, Víctor; Fernández-Lozano, Ignacio; Mont, Lluís; Brugada, Josep; Scornik, Fabiana S; Brugada, Ramon

    2015-01-01

    The heritable cardiovascular disorder long QT syndrome (LQTS), characterized by prolongation of the QT interval on electrocardiogram, carries a high risk of sudden cardiac death. We sought to add new data to the existing knowledge of genetic mutations contributing to LQTS to both expand our understanding of its genetic basis and assess the value of genetic testing in clinical decision-making. Direct sequencing of the five major contributing genes, KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2, was performed in a cohort of 115 non-related LQTS patients. Pathogenicity of the variants was analyzed using family segregation, allele frequency from public databases, conservation analysis, and Condel and Provean in silico predictors. Phenotype-genotype correlations were analyzed statistically. Sequencing identified 36 previously described and 18 novel mutations. In 51.3% of the index cases, mutations were found, mostly in KCNQ1, KCNH2, and SCN5A; 5.2% of cases had multiple mutations. Pathogenicity analysis revealed 39 mutations as likely pathogenic, 12 as VUS, and 3 as non-pathogenic. Clinical analysis revealed that 75.6% of patients with QTc≥500 ms were genetically confirmed. Our results support the use of genetic testing of KCNQ1, KCNH2, and SCN5A as part of the diagnosis of LQTS and to help identify relatives at risk of SCD. Further, the genetic tools appear more valuable as disease severity increases. However, the identification of genetic variations in the clinical investigation of single patients using bioinformatic tools can produce erroneous conclusions regarding pathogenicity. Therefore segregation studies are key to determining causality. PMID:24667783

  1. The canine Purkinje fiber: an in vitro model system for acquired long QT syndrome and drug-induced arrhythmogenesis.

    PubMed

    Gintant, G A; Limberis, J T; McDermott, J S; Wegner, C D; Cox, B F

    2001-05-01

    Torsade de pointes is a rare but potentially fatal ventricular arrhythmia associated with drug-induced delayed repolarization and prolongation of the QT interval. To determine if the arrhythmogenic potential of noncardiac drugs can be assessed in vitro, we evaluated the effects of 12 drugs on the action potential duration (APD) of cardiac Purkinje fibers and compared results with clinical observations. APD changes in canine and porcine fibers were evaluated under physiologic conditions (37 degrees C, [K+]0 = 4 mM) using standard microelectrode techniques. Six of seven drugs associated with QT prolongation or torsade de pointes in man (cisapride, erythromycin, grepafloxacin, moxifloxacin, sertindole, and sotalol) affected concentration-dependent prolongation of the APD in canine fibers during slow stimulation (2-s basic cycle length), attaining greater than 15% prolongation at high concentrations (> or = 10-fold clinically encountered plasma levels). Each of five drugs not linked clinically to QT prolongation and torsade de pointes (azithromycin, enalaprilat, fluoxetine, indomethacin, and pinacidil) failed to attain 15% prolongation, with fluoxetine, indomethacin, and pinacidil abbreviating the APD. Drugs eliciting the greatest prolongation also demonstrated prominent reverse rate-dependent effects. The antihistamine terfenadine (linked to dose-dependent QT prolongation and torsade de pointes clinically) only minimally prolonged the APD in canine and porcine fibers (and exerted no effect on midmyocardial fibers from left ventricular free wall) at supratherapeutic concentrations. On the basis of concentration-dependent APD prolongation and reverse rate-dependent effects, this Purkinje fiber model detects six of seven drugs linked clinically to acquired long QT syndrome and torsade de pointes, and clears each of five drugs not associated with repolarization abnormalities (overall 92% accuracy), validating the utility of this Purkinje fiber model in the preclinical

  2. Localization of Romano-Ward long QT syndrome gene, LQTI, to the interval between tyrosine hydroxylase (TH) and D11S1349

    SciTech Connect

    Russell, M.W. |; Hulse, J.E.; Campbell, R.M.

    1995-08-01

    The Romano-Ward long-QT syndrome (RWLQTS) is an autosomal dominant disorder that is characterized by heritable prolongation of the QT interval, syncope, and sudden death. Identification of the gene responsible for this syndrome may aid the diagnosis, management, and treatment of patients with this disease. Furthermore, it may lead to improved understanding of and therapy for other sympathetic-dependent ventricular arrhythmias. 20 refs., 1 fig., 1 tab.

  3. Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Long QT Syndrome

    PubMed Central

    Angrist, Misha; Chandrasekharan, Subhashini; Heaney, Christopher; Cook-Deegan, Robert

    2010-01-01

    Genetic testing for Long QT syndrome (LQTS) exemplifies patenting and exclusive licensing with different outcomes at different times. Exclusive licensing from the University of Utah changed the business model from sole provider to two US providers of LQTS testing. LQTS is associated with mutations in many genes, ten of which are now tested by two competing firms in the United States, PGxHealth and GeneDx. Until 2009, PGxHealth was sole provider, based largely on exclusive rights to patents from the University of Utah and other academic institutions. University of Utah patents were initially licensed to DNA Sciences, whose patent rights were acquired by Gennaissance, and then by Clinical Data, Inc., which owns PGxHealth. In 2002, DNA Sciences “cleared the market” by sending cease and desist patent enforcement letters to university and reference laboratories offering LQTS genetic testing. There was no test on the market for a one- to two-year period. From 2005-2008, most LQTS-related patents were controlled by Clinical Data, Inc., and its subsidiary PGxHealth. BioReference Laboratories, Inc., secured countervailing exclusive patent rights starting in 2006, also from the University of Utah, and broke the PGxHealth monopoly in early 2009, creating a duopoly for genetic testing in the United States, and expanding the number of genes for which commercial testing is available from five to ten. PMID:20393304

  4. Mapping of a gene for long QT syndrome to chromosome 4q25-27

    SciTech Connect

    Schott, J.J.; Charpentier, F.; Peltier, S.

    1995-11-01

    Long QT syndrome (LQTS) is a heterogeneous inherited disorder causing syncope and sudden death from ventricular arrhythmias. A first locus for this disorder was mapped to chromosome 11p15.5. However, locus heterogeneity has been demonstrated in several families, and two other loci have recently been located on chromosomes 7q35-36 and 3p21-24. We used linkage analysis to map the locus in a 65-member family in which LQTS was associated with more marked sinus bradycardia than usual, leading to sinus node dysfunction. Linkage to chromosome 11p15.5, 7q35-36, or 3p21-24 was excluded. Positive linkage was obtained for markers located on chromosome 4q25-27. A maximal LOD score of 7.05 was found for marker D4S402. The identification of a fourth locus for LQTS confirms its genetic heterogeneity. Locus 4q25-27 is associated with a peculiar phenotype within the LQTS entity. 42 refs., 4 figs., 3 tabs.

  5. Novel missense mutation in the cyclic nucleotide-binding domain of HERG causes long QT syndrome

    SciTech Connect

    Satler, C.A.; Walsh, E.P.; Vesely, M.R.

    1996-10-02

    Autosomal-dominant long QT syndrome (LQT) is an inherited disorder, predisposing affected individuals to sudden death from tachyarrhythmias. To identify the gene(s) responsible for LQT, we identified and characterized an LQT family consisting of 48 individuals. DNA was screened with 150 microsatellite polymorphic markers encompassing approximately 70% of the genome. We found evidence for linkage of the LQT phenotype to chromosome 7(q35-36). Marker D7S636 yielded a maximum lod score of 6.93 at a recombination fraction ({theta}) of 0.00. Haplotype analysis further localized the LQT gene within a 6-2-cM interval. HERG encodes a potassium channel which has been mapped to this region. Single-strand conformational polymorphism analyses demonstrated aberrant bands that were unique to all affected individuals. DNA sequencing of the aberrant bands demonstrated a G to A substitution in all affected patients; this point mutation results in the substitution of a highly conserved valine residue with a methionine (V822M) in the cyclic nucleotide-binding domain of this potassium channel. The cosegregation of this distinct mutation with LQT demonstrates that HERG is the LQT gene in this pedigree. Furthermore, the location and character of this mutation suggests that the cyclic nucleotide-binding domain of the potassium channel encoded by HERG plays an important role in normal cardiac repolarization and may decrease susceptibility to ventricular tachyarrhythmias. 38 refs., 7 figs., 2 tabs.

  6. Mapping of a Gene for Long QT Syndrome to Chromosome 4q25-27

    PubMed Central

    Schott, Jean-Jacques; Charpentier, Flavien; Peltier, Sophie; Foley, Patrick; Drouin, Emmanuel; Bouhour, Jean-Brieuc; Donnelly, Patricia; Vergnaud, Gilles; Bachner, Lucien; Moisan, Jean-Paul; Le Marec, Hervé; Pascal, Olivier

    1995-01-01

    Long QT syndrome (LQTS) is a heterogeneous inherited disorder causing syncope and sudden death from ventricular arrhythmias. A first locus for this disorder was mapped to chromosome 11p15.5. However, locus heterogeneity has been demonstrated in several families, and two other loci have recently been located on chromosomes 7q35-36 and 3p21-24. We used linkage analysis to map the locus in a 65-member family in which LQTS was associated with more marked sinus bradycardia than usual, leading to sinus node dysfunction. Linkage to chromosome 11p15.5, 7q35-36, or 3p21-24 was excluded. Positive linkage was obtained for markers located on chromosome 4q25-27. A maximal LOD score of 7.05 was found for marker D4S402. The identification of a fourth locus for LQTS confirms its genetic heterogeneity. Locus 4q25-27 is associated with a peculiar phenotype within the LQTS entity. PMID:7485162

  7. Molecular Diagnosis of Long-QT syndrome at 10 Days of Life by Rapid Whole Genome Sequencing

    PubMed Central

    Priest, James R.; Ceresnak, Scott R.; Dewey, Frederick E.; Malloy-Walton, Lindsey E.; Dunn, Kyla; Grove, Megan E.; Perez, Marco V.; Maeda, Katsuhide; Dubin, Anne M.; Ashley, Euan A.

    2014-01-01

    Background The advent of clinical next generation sequencing is rapidly changing the landscape of rare disease medicine. Molecular diagnosis of long QT syndrome (LQTS) can impact clinical management, including risk stratification and selection of pharmacotherapy based on the type of ion channel affected, but results from current gene panel testing requires 4 to 16 weeks before return to clinicians. Objective A term female infant presented with 2:1 atrioventricular block and ventricular arrhythmias consistent with perinatal LQTS, requiring aggressive treatment including epicardial pacemaker, and cardioverter-defibrillator implantation and sympathectomy on day of life two. We sought to provide a rapid molecular diagnosis for optimization of treatment strategies. Methods We performed CLIA-certified rapid whole genome sequencing (WGS) with a speed-optimized bioinformatics platform to achieve molecular diagnosis at 10 days of life. Results We detected a known pathogenic variant in KCNH2 that was demonstrated to be paternally inherited by followup genotyping. The unbiased assessment of the entire catalog of human genes provided by whole genome sequencing revealed a maternally inherited variant of unknown significance in a novel gene. Conclusions Rapid clinical WGS provides faster and more comprehensive diagnostic information by 10 days of life than standard gene-panel testing. In selected clinical scenarios such as perinatal LQTS, rapid WGS may be able to provide more timely and clinically actionable information than a standard commercial test. PMID:24973560

  8. Late sodium current block for drug-induced long QT syndrome: Results from a prospective clinical trial.

    PubMed

    Johannesen, L; Vicente, J; Mason, J W; Erato, C; Sanabria, C; Waite-Labott, K; Hong, M; Lin, J; Guo, P; Mutlib, A; Wang, J; Crumb, W J; Blinova, K; Chan, D; Stohlman, J; Florian, J; Ugander, M; Stockbridge, N; Strauss, D G

    2016-02-01

    Drug-induced long QT syndrome has resulted in many drugs being withdrawn from the market. At the same time, the current regulatory paradigm for screening new drugs causing long QT syndrome is preventing drugs from reaching the market, sometimes inappropriately. In this study, we report the results of a first-of-a-kind clinical trial studying late sodium (mexiletine and lidocaine) and calcium (diltiazem) current blocking drugs to counteract the effects of hERG potassium channel blocking drugs (dofetilide and moxifloxacin). We demonstrate that both mexiletine and lidocaine substantially reduce heart-rate corrected QT (QTc) prolongation from dofetilide by 20 ms. Furthermore, all QTc shortening occurs in the heart-rate corrected J-Tpeak (J-Tpeak c) interval, the biomarker we identified as a sign of late sodium current block. This clinical trial demonstrates that late sodium blocking drugs can substantially reduce QTc prolongation from hERG potassium channel block and assessment of J-Tpeak c may add value beyond only assessing QTc. PMID:26259627

  9. Long QT, Syndactyly, Joint Contractures, Stroke and Novel CACNA1C Mutation: Expanding the Spectrum of Timothy Syndrome

    PubMed Central

    Gillis, Jane; Burashnikov, Elena; Antzelevitch, Charles; Blaser, Susan; Gross, Gil; Turner, Lesley; Babul-Hirji, Riyana; Chitayat, David

    2011-01-01

    Timothy syndrome (TS) is described as an autosomal dominant condition with the constellation of features including prolonged QT interval, hand and foot abnormalities and mental retardation or autism. Splawski et al. [2004] previously described two phenotypes associated with TS distinguished by two unique and different mutations within the CACNA1C gene. We report on a newborn who presented with prolonged QT interval and associated polymorphic ventricular tachycardia, dysmorphic facial features, syndactyly of the hands and feet and joint contractures, suggestive of TS. He developed a stroke, subsequent intractable seizures and was found to have cortical blindness and later profound developmental delay. Initial targeted mutation analysis did not identify either of the previously described TS associated mutations; however, full gene sequencing detected a novel CACNA1C gene mutation (p.Ala1473Gly). The clinical and genetic findings in our case expand both the clinical and molecular knowledge of TS. PMID:22106044

  10. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling

    PubMed Central

    Adeniran, Ismail; Hancox, Jules C.; Zhang, Henggui

    2013-01-01

    Introduction: Genetic forms of the Short QT Syndrome (SQTS) arise due to cardiac ion channel mutations leading to accelerated ventricular repolarization, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favorable to re-entry. Potential electromechanical consequences of the SQTS are less well-understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. Methods and Results: The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K+ channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on [Ca2+]i transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch-activated channel current (Isac). Without Isac, at a stimulation frequency of 1Hz, the SQTS mutations produced dramatic reductions in the amplitude of [Ca2+]i transients, sarcomere length shortening and contractile force. When Isac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca2+ transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. Conclusion: The incorporation of Isac appears to be an important consideration in modeling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole. PMID

  11. Exome Analyses of Long QT Syndrome Reveal Candidate Pathogenic Mutations in Calmodulin-Interacting Genes.

    PubMed

    Shigemizu, Daichi; Aiba, Takeshi; Nakagawa, Hidewaki; Ozaki, Kouichi; Miya, Fuyuki; Satake, Wataru; Toda, Tatsushi; Miyamoto, Yoshihiro; Fujimoto, Akihiro; Suzuki, Yutaka; Kubo, Michiaki; Tsunoda, Tatsuhiko; Shimizu, Wataru; Tanaka, Toshihiro

    2015-01-01

    Long QT syndrome (LQTS) is an arrhythmogenic disorder that can lead to sudden death. To date, mutations in 15 LQTS-susceptibility genes have been implicated. However, the genetic cause for approximately 20% of LQTS patients remains elusive. Here, we performed whole-exome sequencing analyses on 59 LQTS and 61 unaffected individuals in 35 families and 138 unrelated LQTS cases, after genetic screening of known LQTS genes. Our systematic analysis of familial cases and subsequent verification by Sanger sequencing identified 92 candidate mutations in 88 genes for 23 of the 35 families (65.7%): these included eleven de novo, five recessive (two homozygous and three compound heterozygous) and seventy-three dominant mutations. Although no novel commonly mutated gene was identified other than known LQTS genes, protein-protein interaction (PPI) network analyses revealed ten new pathogenic candidates that directly or indirectly interact with proteins encoded by known LQTS genes. Furthermore, candidate gene based association studies using an independent set of 138 unrelated LQTS cases and 587 controls identified an additional novel candidate. Together, mutations in these new candidates and known genes explained 37.1% of the LQTS families (13 in 35). Moreover, half of the newly identified candidates directly interact with calmodulin (5 in 11; comparison with all genes; p=0.042). Subsequent variant analysis in the independent set of 138 cases identified 16 variants in the 11 genes, of which 14 were in calmodulin-interacting genes (87.5%). These results suggest an important role of calmodulin and its interacting proteins in the pathogenesis of LQTS. PMID:26132555

  12. The long QT syndrome: a transatlantic clinical approach to diagnosis and therapy.

    PubMed

    Schwartz, Peter J; Ackerman, Michael J

    2013-10-01

    The mind-boggling progress in the understanding of the molecular mechanisms underlying the long QT syndrome (LQTS) has been the subject of many articles and reviews. Still, when it comes to the management of the patients affected by this life-threatening disorder, too many errors still take place, both in the diagnostic process and in the therapeutic choices. The price of these errors is paid by the patients and their families. This review is not directed to the relatively small number of LQTS experts who know what to do. It does not deal with genetics, with epidemiology, or with the well-known clinical manifestations. We have focused solely on the approach to diagnosis and therapy and we have directed this review to the average clinical cardiologist who, in his/her practice, sees occasionally patients affected or suspected to be affected by LQTS; the cardiologist who may know enough to manage them but not enough to be completely confident on his/her most critical choices. We have provided our personal views without making any attempt to blend differences whenever present. On most issues we agree fully but where we do not, we make it clear to the reader by indicating who is thinking what. The result may be unconventional, but it mirrors the challenges, often severe, that we all face in managing and protecting these patients from sudden death while also helping them live and thrive despite their diagnosis. We trust that this unabashed presentation of our clinical approach will be useful for both cardiologists and patients. PMID:23509228

  13. Cellular mechanisms of ventricular arrhythmias in a mouse model of Timothy syndrome (long QT syndrome 8).

    PubMed

    Drum, Benjamin M L; Dixon, Rose E; Yuan, Can; Cheng, Edward P; Santana, Luis F

    2014-01-01

    Ca(2+) flux through l-type CaV1.2 channels shapes the waveform of the ventricular action potential (AP) and is essential for excitation-contraction (EC) coupling. Timothy syndrome (TS) is a disease caused by a gain-of-function mutation in the CaV1.2 channel (CaV1.2-TS) that decreases inactivation of the channel, which increases Ca(2+) influx, prolongs APs, and causes lethal arrhythmias. Although many details of the CaV1.2-TS channels are known, the cellular mechanisms by which they induce arrhythmogenic changes in intracellular Ca(2+) remain unclear. We found that expression of CaV1.2-TS channels increased sarcolemmal Ca(2+) "leak" in resting TS ventricular myocytes. This resulted in higher diastolic [Ca(2+)]i in TS ventricular myocytes compared to WT. Accordingly, TS myocytes had higher sarcoplasmic reticulum (SR) Ca(2+) load and Ca(2+) spark activity, larger amplitude [Ca(2+)]i transients, and augmented frequency of Ca(2+) waves. The large SR Ca(2+) release in TS myocytes had a profound effect on the kinetics of CaV1.2 current in these cells, increasing the rate of inactivation to a high, persistent level. This limited the amount of influx during EC coupling in TS myocytes. The relationship between the level of expression of CaV1.2-TS channels and the probability of Ca(2+) wave occurrence was non-linear, suggesting that even low levels of these channels were sufficient to induce maximal changes in [Ca(2+)]i. Depolarization of WT cardiomyocytes with a TS AP waveform increased, but did not equalize [Ca(2+)]i, compared to depolarization of TS myocytes with the same waveform. We propose that CaV1.2-TS channels increase [Ca(2+)] in the cytosol and the SR, creating a Ca(2+)overloaded state that increases the probability of arrhythmogenic spontaneous SR Ca(2+) release. PMID:24215710

  14. Synchronous Systolic Subcellular Ca2+-Elevations Underlie Ventricular Arrhythmia in Drug-Induced Long QT Type 2

    PubMed Central

    Kim, Jong J.; Němec, Jan; Li, Qiao; Salama, Guy

    2015-01-01

    Background Repolarization-delay is a common clinical problem which can promote ventricular arrhythmias. In myocytes, abnormal sarcoplasmic reticulum Ca2+-release is proposed as the mechanism that causes early afterdepolarizations, the cellular equivalent of ectopic-activity in drug-induced long QT syndrome. A crucial missing link is how such a stochastic process can overcome the source-sink mismatch to depolarize sufficient ventricular tissue to initiate arrhythmias. Methods and Results Optical maps of action potentials (APs) and Ca2+-transients (CaT) from Langendorff rabbit hearts were measured at low (150×150 μm2/pixel) and high (1.5×1.5 μm2/pixel) resolution before and during arrhythmias. Drug-induced long QT type 2, elicited with dofetilide inhibition, produced spontaneous Ca2+-elevations during diastole and systole, before the onset of arrhythmias. Diastolic Ca2+− waves appeared randomly, propagated within individual myocytes, were out-of-phase with adjacent myocytes and often died-out. Systolic secondary Ca2+− elevations were synchronous within individual myocytes, appeared 188±30ms after the AP-upstroke, occurred during high cytosolic-Ca2+ (40–60% of peak-CaT), appeared first in small islands (0.5×0.5 mm2) that enlarged and spread throughout the epicardium. Synchronous systolic Ca2+-elevations preceded voltage-depolarizations (9.2±5ms, n=5) and produced pronounced Spatial Heterogeneities of CaT-durations and AP-durations. Early afterdepolarizations originating from sites with the steepest gradients of membrane-potential propagated and initiated arrhythmias. Interestingly, more complex subcellular Ca2+-dynamics (multiple chaotic Ca2+-waves) occurred during arrhythmias. K201, a ryanodine receptor stabilizer, eliminated Ca2+-elevations and arrhythmias. Conclusions The results indicate that systolic and diastolic Ca2+-elevations emanate from sarcoplasmic reticulum Ca2+-release and systolic Ca2+-elevations are synchronous because of high cytosolic

  15. Potassium Channel Block and Novel Autoimmune-Associated Long QT Syndrome.

    PubMed

    Boutjdir, Mohamed; Lazzerini, Pietro Enea; Capecchi, Pier Leopoldo; Laghi-Pasini, Franco; El-Sherif, Nabil

    2016-06-01

    This article reviews advances in the pathogenesis of anti-SSA/Ro antibody-induced corrected QT (QTc) prolongation in patients with autoimmune diseases; particularly connective tissue disease (CTD). Evidence shows that anti-SSA/Ro antibody-positive patients with CTD show QTc prolongation and complex ventricular arrhythmias. Molecular and functional data provide evidence that the human ether-a-go-go-related gene potassium channel conducting the rapidly activating delayed rectifier potassium current is directly inhibited by anti-SSA/Ro antibodies, resulting in action potential duration prolongation leading to QT interval lengthening. Routine electrocardiogram screening in anti-SSA/Ro antibody-positive patients and counseling for patients with other QTc prolonging risk factors is recommended. PMID:27261828

  16. Electro-mechanical dysfunction in long QT syndrome: Role for arrhythmogenic risk prediction and modulation by sex and sex hormones.

    PubMed

    Lang, C N; Menza, M; Jochem, S; Franke, G; Perez Feliz, S; Brunner, M; Koren, G; Zehender, M; Bugger, H; Jung, B A; Foell, D; Bode, C; Odening, K E

    2016-01-01

    Long QT syndrome (LQTS) is a congenital arrhythmogenic channelopathy characterized by impaired cardiac repolarization. Increasing evidence supports the notion that LQTS is not purely an "electrical" disease but rather an "electro-mechanical" disease with regionally heterogeneously impaired electrical and mechanical cardiac function. In the first part, this article reviews current knowledge on electro-mechanical (dys)function in LQTS, clinical consequences of the observed electro-mechanical dysfunction, and potential underlying mechanisms. Since several novel imaging techniques - Strain Echocardiography (SE) and Magnetic Resonance Tissue Phase Mapping (TPM) - are applied in clinical and experimental settings to assess the (regional) mechanical function, advantages of these non-invasive techniques and their feasibility in the clinical routine are particularly highlighted. The second part provides novel insights into sex differences and sex hormone effects on electro-mechanical cardiac function in a transgenic LQT2 rabbit model. Here we demonstrate that female LQT2 rabbits exhibit a prolonged time to diastolic peak - as marker for contraction duration and early relaxation - compared to males. Chronic estradiol-treatment enhances these differences in time to diastolic peak even more and additionally increases the risk for ventricular arrhythmia. Importantly, time to diastolic peak is particularly prolonged in rabbits exhibiting ventricular arrhythmia - regardless of hormone treatment - contrasting with a lack of differences in QT duration between symptomatic and asymptomatic LQT2 rabbits. This indicates the potential added value of the assessment of mechanical dysfunction in future risk stratification of LQTS patients. PMID:26718598

  17. Buprenorphine as a safe alternative to methadone in a patient with acquired long QT syndrome: a case report.

    PubMed

    de Jong, I M; de Ruiter, G S

    2013-05-01

    A 52-year-old man with a medical history of intravenous drug abuse was admitted to our hospital with syncope due to torsades de pointes (TdP). Two days earlier, he had used methadone. The electrocardiogram showed a prolonged corrected QT interval (QTc) of 600 ms. Continuous telemetry observation showed multiple episodes of TdP. The patient was diagnosed with bradyarrhythmia-induced TdP with acquired long QT syndrome resulting from methadone use. The QTc normalised within 2 weeks after discontinuation of the methadone. In this case of a patient with opioid dependency, there is a reasonable risk of repeated methadone use. Therefore, implantable cardioverter defibrillator or pacemaker implantation is justified but risky because of possible infections when using intravenous drugs. Given the high mortality rates seen in untreated illicit opioid users, this patient needs an alternative pharmacological treatment. Buprenorphine is an opiate-receptor agonist associated with less QTc prolongation. The patient was referred to a rehab clinic and treated with an oral combination of buprenorphine and naloxone (Suboxone). During this therapy, his QTc remained normal. PMID:22020456

  18. Fetal ventricular tachycardia secondary to long QT syndrome treated with maternal intravenous magnesium: case report and review of the literature.

    PubMed

    Simpson, J M; Maxwell, D; Rosenthal, E; Gill, H

    2009-10-01

    Ventricular tachycardia is a very rare fetal arrhythmia accounting for fewer than 2% of fetal tachycardias. We describe a fetus presenting at 30 weeks' gestation with ventricular tachycardia at a rate of 220 beats per min and fetal hydrops. The tachycardia was unresponsive to flecainide but was controlled within 12 h by an intravenous infusion of magnesium to the mother. Despite rapid control of the arrhythmia the fetus developed severe periventricular leukomalacia before birth for which a poor neurological prognosis was given. The baby was delivered preterm at 32 weeks' gestation and died on the sixth day after birth. Long QT syndrome was identified postnatally on the electrocardiogram, and was confirmed by genetic testing which showed a mutation in the KCNH2 gene (p.T613M). PMID:19731233

  19. Case ascertainment and estimated incidence of drug-induced long-QT syndrome: study in Southwest France

    PubMed Central

    Molokhia, Mariam; Pathak, Atul; Lapeyre-Mestre, Maryse; Caturla, Laetitia; Montastruc, Jean Louis; McKeigue, Paul

    2008-01-01

    AIMS The aim of this study was to investigate the incidence and reporting rate of drug-induced long-QT syndrome (LQTS) in France [defined by evidence of torsades de pointes (TdP), QT prolongation and exposure to a relevant drug] and to assess feasibility of case collection for drug-induced LQTS. METHODS A retrospective population-based study was carried out in Southwest France in five institutions: three main hospitals, one private clinic and one cardiac emergency unit, searched from 1 January 1999 to 1 January 2005 (population coverage of 614 000). The study population consisted of 861 cases with International Classification of Diseases-10 diagnostic codes for ventricular tachycardia (I147.2), ventricular fibrillation (I149.0) and sudden cardiac death (I146.1) from hospital discharge summaries, supplemented by cases reported to national or regional pharmacovigilance systems, and voluntary reporting by physicians, validated according to internationally defined criteria for drug-induced LQTS. RESULTS Of 861 patients coded with arrhythmias or sudden cardiac death, there were 40 confirmed surviving acquired cases of drug-induced LQTS. We estimated that the incidence of those who survive to reach hospital drug-induced LQTS is approximately 10.9 per million annually in France (95% confidence interval 7.8, 14.8). CONCLUSIONS Many cases of drug-induced LQTS may not survive before they reach hospital, as the reporting rate for drug-induced LQTS identified through the cardiology records and also reported to pharmacovigilance systems for the Midi-Pyrenees area is 3/40 (7.5%). Using the methods outlined it is possible to assemble cases to study genetic susceptibility to drug-induced LQTS and adapt these methods more widely. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Drug-induced long-QT syndrome (LQTS) is a potentially fatal condition that has led to a number of postmarketing withdrawals in recent years. However, many cases may not survive long enough to reach hospital, and

  20. Calcium oscillations and T-wave lability precede ventricular arrhythmias in acquired long QT type 2

    PubMed Central

    Němec, Jan; Kim, Jong J.; Gabris, Beth; Salama, Guy

    2010-01-01

    Background Alternans of intracellular Ca2+ (Cai) underlies T-wave alternans, a predictor of cardiac arrhythmias. A related phenomenon, T-Wave Lability (TWL), precedes Torsade de Pointes (TdP) in patients and animal models with impaired repolarization. However, the role of Cai in TWL remains unexplored. Methods Action potentials (APs) and Cai transients, (CaTs) were mapped optically from paced Langendorff female rabbit hearts (n=8) at 1.2s cycle length, after AV node ablation. Hearts were perfused with normal Tyrode's solution then with dofetilide (0.5 μM) and reduced [K+] (2 mM) and [Mg2+] (0.5 mM) to elicit long QT type 2 (LQT2). Lability of EKG, voltage and Cai signals were evaluated during regular paced rhythm, before and after dofetilide perfusion. Results In LQT2, lability of Cai, voltage and EKG signals increased during paced rhythm, before the appearance of early afterdepolarizations (EADs). LQT2 resulted in AP prolongation and multiple (1-3) additional Cai upstrokes, while APs remained monophasic. When EADs appeared, Cai rose before voltage upstrokes at the origins of propagating EADs. Interventions (i.e. ryanodine and thapsigargin, n=3 or low [Ca]o and nifedipine, n=4) that suppressed Cai oscillations also abolished EADs. Conclusions In LQT2, Cai oscillations (CaiO) precede EADs by minutes, indicating that they result from spontaneous sarcoplasmic reticulum Ca2+ release rather than spontaneous ICaL reactivation. CaiO likely produce oscillations of Na/Ca exchange current, INCX. Depolarizing INCX during the AP plateau contributes to the generation of EADs by re-activating Ca2+-channels that have recovered from inactivation. TWL reflects CaTs and APs lability that occur before EADs and TdP. PMID:20599524

  1. Subject identification via ECG fiducial-based systems: influence of the type of QT interval correction.

    PubMed

    Gargiulo, Francesco; Fratini, Antonio; Sansone, Mario; Sansone, Carlo

    2015-10-01

    Electrocardiography (ECG) has been recently proposed as biometric trait for identification purposes. Intra-individual variations of ECG might affect identification performance. These variations are mainly due to Heart Rate Variability (HRV). In particular, HRV causes changes in the QT intervals along the ECG waveforms. This work is aimed at analysing the influence of seven QT interval correction methods (based on population models) on the performance of ECG-fiducial-based identification systems. In addition, we have also considered the influence of training set size, classifier, classifier ensemble as well as the number of consecutive heartbeats in a majority voting scheme. The ECG signals used in this study were collected from thirty-nine subjects within the Physionet open access database. Public domain software was used for fiducial points detection. Results suggested that QT correction is indeed required to improve the performance. However, there is no clear choice among the seven explored approaches for QT correction (identification rate between 0.97 and 0.99). MultiLayer Perceptron and Support Vector Machine seemed to have better generalization capabilities, in terms of classification performance, with respect to Decision Tree-based classifiers. No such strong influence of the training-set size and the number of consecutive heartbeats has been observed on the majority voting scheme. PMID:26143963

  2. Some legal, social, and ethical issues related to the genetic testing revolution, as exemplified in the long QT syndrome.

    PubMed

    Liebman, J

    2001-01-01

    Molecular Biology is revolutionizing medicine. There are a number of conditions, particularly exemplified by the long QT syndrome, where there is no structural abnormality but where a subset of patients is prone to sudden death. The issues of appropriate care are very complex, because there is tremendous overlap between patients with prolongation of the QT who remain asymptomatic and those with prolongation who are very symptomatic. Furthermore, even those who are prone to have one of the abnormal genes, may be asymptomatic. A large literature has developed, from both legal and ethical aspects, related to the fact that in genetic disease per se, not only is the person at risk, but so are many members of his or her family. A large literature has also developed as to which should be prime, the patient's privacy or the responsibility to make sure the entire family is knowledgeable and perhaps tested. At the present moment our care is based upon the fact that the precise identification of the gene is not yet available on a routine basis. This of course, may soon change. But we will still have difficult decisions to make. Obviously, we have a responsibility as physicians to be as precise as our discipline allows, but we have a responsibility to be flexible. Relief of anxiety, as an example, has to be a prime issue. This is certainly the case now when any information related to infants with potential sudden death is still incomplete. We must not approach the care of the patient in such a way that protection of the physician may interfere with appropriate care. The discussion necessarily includes a variety of aspects. PMID:11781954

  3. Re-evaluating the efficacy of β-adrenergic agonists and antagonists in long QT-3 syndrome through computational modelling

    PubMed Central

    Ahrens-Nicklas, Rebecca C.; Clancy, Colleen E.; Christini, David J.

    2009-01-01

    Aims Long QT syndrome (LQTS) is a heterogeneous collection of inherited cardiac ion channelopathies characterized by a prolonged electrocardiogram QT interval and increased risk of sudden cardiac death. β-Adrenergic blockers are the mainstay of treatment for LQTS. While their efficacy has been demonstrated in LQTS patients harbouring potassium channel mutations, studies of β-blockers in subtype 3 (LQT3), which is caused by sodium channel mutations, have produced ambiguous results. In this modelling study, we explore the effects of β-adrenergic drugs on the LQT3 phenotype. Methods and results In order to investigate the effects of β-adrenergic activity and to identify sources of ambiguity in earlier studies, we developed a computational model incorporating the effects of β-agonists and β-blockers into an LQT3 mutant guinea pig ventricular myocyte model. β-Activation suppressed two arrhythmogenic phenomena, transmural dispersion of repolarization and early after depolarizations, in a dose-dependent manner. However, the ability of β-activation to prevent cardiac conduction block was pacing-rate-dependent. Low-dose β-blockade by propranolol reversed the beneficial effects of β-activation, while high dose (which has off-target sodium channel effects) decreased arrhythmia susceptibility. Conclusion These results demonstrate that β-activation may be protective in LQT3 and help to reconcile seemingly conflicting results from different experimental models. They also highlight the need for well-controlled clinical investigations re-evaluating the use of β-blockers in LQT3 patients. PMID:19264765

  4. Long QT Syndrome Leading to Multiple Cardiac Arrests After Posaconazole Administration in an Immune-Compromised Patient with Sepsis: An Unusual Case Report

    PubMed Central

    Panos, George; Velissaris, Dimitrios; Karamouzos, Vasilios; Matzaroglou, Charalampos; Tyllianakis, Minos

    2016-01-01

    Patient: Female, 26 Final Diagnosis: Sepsis • drug induced long QT syndrome Symptoms: Cardiac arrest • cardiac arrhythmia • fever • Qt prolongation Medication: Posaconazole Clinical Procedure: Pacemaker insertion Specialty: Infectious Diseases Objective: Rare disease Background: We present the case of a septic patient with severe immunodeficiency, who developed QT interval prolongation followed by episodes of lethal cardiac arrhythmia. Cardiac events occurred after posaconazole administration, incriminating posaconazole use, alone or in combination with voriconazole, as the culpable agent. Case Report: A 26-year-old female patient underwent orthopedic surgery to remove ectopic calcifications in her left hip joint. On the first post-operative day she became septic due to a surgical wound infection. Despite being treated according to the therapeutic protocols for sepsis, no clinical improvement was noticed and further assessment revealed an underlying immunodeficiency. Considering the underlying immunodeficiency and to that point poor clinical response, an antifungal agent was added to the antibiotic regiment. Following discontinuation of multiple antifungal agents due to adverse effects, posaconazole was administered. Posaconazole oral intake was followed by episodes of bradycardia and QT interval prolongation. The patient suffered continuous incidents of cardiac arrest due to polymorphic ventricular tachycardia (torsades des pointes) that degenerated to lethal ventricular fibrillation. Posaconazole was immediately discontinued and a temporary pacemaker was installed. The patient finally recovered without any neurological deficit, and was discharged in a good clinical status. Conclusions: Close cardiac monitoring is recommended in cases where posaconazole administration is combined with coexisting risk factors, as they may lead to severe ECG abnormalities and cardiac arrhythmias such as long QT interval syndrome and torsades de pointes. Posaconazole

  5. Importance of QT interval in clinical practice.

    PubMed

    Ambhore, Anand; Teo, Swee-Guan; Bin Omar, Abdul Razakjr; Poh, Kian-Keong

    2014-12-01

    Long QT interval is an important finding that is often missed by electrocardiogram interpreters. Long QT syndrome (inherited and acquired) is a potentially lethal cardiac channelopathy that is frequently mistaken for epilepsy. We present a case of long QT syndrome with multiple cardiac arrests presenting as syncope and seizures. The long QTc interval was aggravated by hypomagnesaemia and drugs, including clarithromycin and levofloxacin. Multiple drugs can cause prolongation of the QT interval, and all physicians should bear this in mind when prescribing these drugs. PMID:25630313

  6. Isogenic human pluripotent stem cell pairs reveal the role of a KCNH2 mutation in long-QT syndrome

    PubMed Central

    Bellin, Milena; Casini, Simona; Davis, Richard P; D'Aniello, Cristina; Haas, Jessica; Ward-van Oostwaard, Dorien; Tertoolen, Leon G J; Jung, Christian B; Elliott, David A; Welling, Andrea; Laugwitz, Karl-Ludwig; Moretti, Alessandra; Mummery, Christine L

    2013-01-01

    Patient-specific induced pluripotent stem cells (iPSCs) will assist research on genetic cardiac maladies if the disease phenotype is recapitulated in vitro. However, genetic background variations may confound disease traits, especially for disorders with incomplete penetrance, such as long-QT syndromes (LQTS). To study the LQT2-associated c.A2987T (N996I) KCNH2 mutation under genetically defined conditions, we derived iPSCs from a patient carrying this mutation and corrected it. Furthermore, we introduced the same point mutation in human embryonic stem cells (hESCs), generating two genetically distinct isogenic pairs of LQTS and control lines. Correction of the mutation normalized the current (IKr) conducted by the HERG channel and the action potential (AP) duration in iPSC-derived cardiomyocytes (CMs). Introduction of the same mutation reduced IKr and prolonged the AP duration in hESC-derived CMs. Further characterization of N996I-HERG pathogenesis revealed a trafficking defect. Our results demonstrated that the c.A2987T KCNH2 mutation is the primary cause of the LQTS phenotype. Precise genetic modification of pluripotent stem cells provided a physiologically and functionally relevant human cellular context to reveal the pathogenic mechanism underlying this specific disease phenotype. PMID:24213244

  7. Identification of a KCNQ1 Polymorphism Acting as a Protective Modifier against Arrhythmic Risk in Long QT Syndrome

    PubMed Central

    Duchatelet, Sabine; Crotti, Lia; Peat, Rachel A.; Denjoy, Isabelle; Itoh, Hideki; Berthet, Myriam; Ohno, Seiko; Fressart, Véronique; Monti, Maria Cristina; Crocamo, Cristina; Pedrazzini, Matteo; Dagradi, Federica; Vicentini, Alessandro; Klug, Didier; Brink, Paul A.; Goosen, Althea; Swan, Heikki; Toivonen, Lauri; Lahtinen, Annukka M.; Kontula, Kimmo; Shimizu, Wataru; Horie, Minoru; George, Alfred L.; Trégouët, David-Alexandre; Guicheney, Pascale; Schwartz, Peter J.

    2013-01-01

    Background Long-QT Syndrome (LQTS) is characterized by such striking clinical heterogeneity, that even among family members carrying the same mutation, clinical outcome can range between sudden death to no symptoms. We investigated the role of genetic variants as modifiers of risk for cardiac events in LQTS patients. Methods and Results In a matched case-control study including 112 LQTS patient duos from France, Italy and Japan, 25 polymorphisms were genotyped based on either their association with QTc duration in healthy populations or on their role in adrenergic responses. The duos were composed of two relatives harboring the same heterozygous KCNQ1 or KCNH2 mutation; one with cardiac events and one asymptomatic and untreated. The findings were then validated in two independent founder populations totaling 174 symptomatic and 162 asymptomatic LQTS patients, and a meta-analysis was performed. The KCNQ1 rs2074238 T-allele was significantly associated with a decreased risk of symptoms 0.34 [0.19 – 0.61] (p<0.0002) and with shorter QTc (p<0.0001) in the combined discovery and replication cohorts. Conclusions We provide evidence that the KCNQ1 rs2074238 polymorphism is an independent risk modifier with the minor T-allele conferring protection against cardiac events in LQTS patients. This finding is a step toward a novel approach for risk stratification in LQTS patients. PMID:23856471

  8. Genetic variants for long QT syndrome among infants and children from a statewide newborn hearing screening program cohort

    PubMed Central

    Chang, Ruey-Kang R.; Lan, Yueh-Tze; Silka, Michael J.; Morrow, Hallie; Kwong, Alan; Smith-Lang, Janna; Wallerstein, Robert; Lin, Henry J.

    2014-01-01

    Objectives Autosomal recessive long QT syndrome (LQTS), or Jervell and Lange-Nielsen syndrome (JLNS), can be associated with sensorineural hearing loss (SNHL). We aimed to explore newborn hearing screening combined with ECGs for early JLNS detection. Study design We conducted California statewide, prospective ECG screening of children ≤6 years of age with unilateral or bilateral, severe or profound, sensorineural or mixed hearing loss. Families were identified through newborn hearing screening and interviewed about medical and family histories. Twelve-lead ECGs were obtained. Those with positive histories or QTc intervals ≥450 ms had repeat ECGs. DNA sequencing of 12 LQTS genes was performed for repeat QTc intervals ≥450 ms. Results We screened 707 subjects by ECGs (number screened/number of responses = 91%; number of responses/number of families who were mailed invitations = 54%). Of these, 73 had repeat ECGs, and 19 underwent gene testing. No subject had homozygous or compound heterozygous LQTS mutations, as in JLNS. However, 3 individuals (with QTc intervals of 472, 457, and 456 ms, respectively) were heterozygous for variants that cause truncation or missplicing: 2 in KCNQ1 (c.1343dupC or p.Glu449Argfs*14; c.1590+1G>A or p.Glu530sp) and 1 in SCN5A (c.5872C>T or p.Arg1958*). Conclusions In contrast to reports of JLNS in up to 4% of children with SNHL, we found no examples of JLNS. Because the 3 variants identified were unrelated to hearing, they likely represent the prevalence of potential LQTS mutations in the general population. Further studies are needed to define consequences of such mutations and assess the overall prevalence. PMID:24388587

  9. Phenotype of Children with QT Prolongation Identified Using an Institution-Wide QT Alert System.

    PubMed

    Anderson, Heather N; Bos, J Martijn; Haugaa, Kristina H; Morlan, Bruce W; Tarrell, Robert F; Caraballo, Pedro J; Ackerman, Michael J

    2015-10-01

    QT prolongation is an independent risk factor for cardiovascular mortality in adults. However, there is little information available on pediatric patients with QT prolongation and their outcomes. Herein, we evaluated the prevalence of QT prolongation in pediatric patients identified by an institution-wide QT alert system, and the spectrum of their phenotype. Patients with documented QT prolongation on an ECG obtained between November 2010 and June 2011 were included. There were 1303 pediatric ECGs, and 68 children had electrographically isolated QT prolongation. Comprehensive review of medical records was performed with particular attention to QT-prolonging clinical, laboratory, and medication data, which were summarized into a pro-QTc score. Overall, 68 (5 %) pediatric patients had isolated QT prolongation. The mean age of this pediatric cohort was 9 ± 6 years, and the average QTc was 494 ± 42 ms. All children had 1 or more QT-prolonging risk factor(s), most commonly QT-prolonging medications. One patient was identified with congenital long QT syndrome (LQTS), which was not previously diagnosed. In one-year follow-up, only one pediatric death (non-cardiac) occurred (1.5 %). Potentially QT-offending/pro-arrhythmic medications were changed in 80 % of pediatric patients after the physician received the QT alert. Children with QT prolongation had very low mortality and minimal polypharmacy. Still, medications and other modifiable conditions were the most common causes of QT prolongation. Children with a prolonged QTc should be evaluated for modifiable QT-prolonging factors. However, if no risk factors are present or the QTc does not attenuate after risk factor modification/removal, the child should be evaluated for congenital LQTS. PMID:25845942

  10. [Excessive energy drink consumption caused marked QT prolongation. Case report].

    PubMed

    Tomcsányi, János; Jávor, Kinga

    2015-10-25

    The authors report a case of a 22-year-old man with atypical chest pain after consumption of six energy drinks (1.5 liter containing 470 mg coffein) with vodka. On admission ECG showed marked QT/QTc prolongation (QT/QTc, 520/580 msec). Next day the QT/QTc returned to fully normal (QT/QTc, 360/430 msec). It was assumed that the patient had a silent long QT syndrome and that high dose of highly caffeinated energy drink triggered the (paradoxical) prolonged QT/QTc. The authors conclude that excessive energy drink intake with alcohol or during physical exercise should be avoided. PMID:26477618

  11. Asymmetry of parental origin in long QT syndrome: preferential maternal transmission of KCNQ1 variants linked to channel dysfunction.

    PubMed

    Itoh, Hideki; Berthet, Myriam; Fressart, Véronique; Denjoy, Isabelle; Maugenre, Svetlana; Klug, Didier; Mizusawa, Yuka; Makiyama, Takeru; Hofman, Nynke; Stallmeyer, Birgit; Zumhagen, Sven; Shimizu, Wataru; Wilde, Arthur A M; Schulze-Bahr, Eric; Horie, Minoru; Tezenas du Montcel, Sophie; Guicheney, Pascale

    2016-08-01

    Transmission distortion of disease-causing alleles in long QT syndrome (LQTS) has been reported, suggesting a potential role of KCNQ1 and KCNH2 in reproduction. This study sought to investigate parental transmission in LQTS families according to ethnicity, gene loci (LQT1-3: KCNQ1, KCNH2, and SCN5A) or severity of channel dysfunction. We studied 3782 genotyped members from 679 European and Japanese LQTS families (2748 carriers). We determined grandparental and parental origins of variant alleles in 1903 children and 624 grandchildren, and the grandparental origin of normal alleles in healthy children from 44 three-generation control families. LQTS alleles were more of maternal than paternal origin (61 vs 39%, P<0.001). The ratio of maternally transmitted alleles in LQT1 (66%) was higher than in LQT2 (56%, P<0.001) and LQT3 (57%, P=0.03). Unlike the Mendelian distribution of grandparental alleles seen in control families, variant grandparental LQT1 and LQT2 alleles in grandchildren showed an excess of maternally transmitted grandmother alleles. For LQT1, maternal transmission differs according to the variant level of dysfunction with 68% of maternal transmission for dominant negative or unknown functional consequence variants vs 58% for non-dominant negative and variants leading to haploinsufficiency, P<0.01; however, for LQT2 or LQT3 this association was not significant. An excess of disease-causing alleles of maternal origin, most pronounced in LQT1, was consistently found across ethnic groups. This observation does not seem to be linked to an imbalance in transmission of the LQTS subtype-specific grandparental allele, but to the potential degree of potassium channel dysfunction. PMID:26669661

  12. The link between abnormal calcium handling and electrical instability in acquired long QT syndrome - Does calcium precipitate arrhythmic storms?

    PubMed

    Němec, Jan; Kim, Jong J; Salama, Guy

    2016-01-01

    Release of Ca(2+) ions from sarcoplasmic reticulum (SR) into myocyte cytoplasm and their binding to troponin C is the final signal form myocardial contraction. Synchronous contraction of ventricular myocytes is necessary for efficient cardiac pumping function. This requires both shuttling of Ca(2+) between SR and cytoplasm in individual myocytes, and organ-level synchronization of this process by means of electrical coupling among ventricular myocytes. Abnormal Ca(2+) release from SR causes arrhythmias in the setting of CPVT (catecholaminergic polymorphic ventricular tachycardia) and digoxin toxicity. Recent optical mapping data indicate that abnormal Ca(2+) handling causes arrhythmias in models of both repolarization impairment and profound bradycardia. The mechanisms involve dynamic spatial heterogeneity of myocardial Ca(2+) handling preceding arrhythmia onset, cell-synchronous systolic secondary Ca(2+) elevation (SSCE), as well as more complex abnormalities of intracellular Ca(2+) handling detected by subcellular optical mapping in Langendorff-perfused hearts. The regional heterogeneities in Ca(2+) handling cause action potential (AP) heterogeneities through sodium-calcium exchange (NCX) activation and eventually overwhelm electrical coupling of the tissue. Divergent Ca(2+) dynamics among different myocardial regions leads to temporal instability of AP duration and - on the patient level - in T wave lability. Although T-wave alternans has been linked to cardiac arrhythmias, non-alternans lability is observed in pre-clinical models of the long QT syndrome (LQTS) and CPVT, and in LQTS patients. Analysis of T wave lability may provide a real-time window on the abnormal Ca(2+) dynamics causing specific arrhythmias such as Torsade de Pointes (TdP). PMID:26631594

  13. Improved Clinical Risk Stratification in Patients with Long QT Syndrome? Novel Insights from Multi-Channel ECGs

    PubMed Central

    Samol, Alexander; Gönes, Mehmet; Zumhagen, Sven; Bruns, Hans-Jürgen; Paul, Matthias; Vahlhaus, Christian; Waltenberger, Johannes; Schulze-Bahr, Eric; Eckardt, Lars; Mönnig, Gerold

    2016-01-01

    Background We investigated whether multichannel ECG-recordings are useful to risk-stratify patients with congenital long-QT syndrome (LQTS) for risk of sudden cardiac death under optimized medical treatment. Methods In 34 LQTS-patients (11 male; age 31±13 years, QTc 478±51ms; LQT1 n = 8, LQT2 n = 15) we performed a standard 12-channel ECG and a 120-channel body surface potential mapping. The occurrence of clinical events (CE; syncope, torsade de pointes (TdP), sudden cardiac arrest (SCA)) was documented and correlated with different ECG-parameters in all lead positions. Results Seven patients developed TdP, four survived SCA and 12 experienced syncope. 12/34 had at least one CE. CE was associated with a longer QTc-interval (519±43ms vs. 458±42ms; p = 0.001), a lower T-wave integral (TWI) on the left upper chest (-1.2±74.4mV*ms vs. 63.0±29.7mV*ms; p = 0.001), a lower range of T-wave amplitude (TWA) in the region of chest lead V8 (0.10±0.08mV vs. 0.18±0.07mV; p = 0.008) and a longer T-peak-T-end time (TpTe) in lead V1 (98±23ms vs. 78±26ms; p = 0.04). Receiver-operating-characteristic (ROC) analyses revealed a sensitivity of 96% and a specificity of 75% (area under curve (AUC) 0.89±0.06, p = 0.001) at a cut-off value of 26.8mV*ms for prediction of CE by TWI, a sensitivity of 86% and a specificity of 83% at a cut-off value of 0.11mV (AUC 0.83±0.09, p = 0.002) for prediction of CE by TWA and a sensitivity of 83% and a specificity of 73% at a cut-off value of 87ms (AUC 0.80±0.07, p = 0.005) for prediction of CE by TpTe. Conclusions Occurrence of CE in LQTS-patients seems to be associated with a prolonged, low-amplitude T-wave. PMID:27379800

  14. Role of Sarcoplasmic Reticulum Calcium in Development of Secondary Calcium Rise and Early Afterdepolarizations in Long QT Syndrome Rabbit Model

    PubMed Central

    Chang, Po-Cheng; Wo, Hung-Ta; Lee, Hui-Ling; Lin, Shien-Fong; Wen, Ming-Shien; Chu, Yen; Yeh, San-Jou; Chou, Chung-Chuan

    2015-01-01

    Background L-type calcium current reactivation plays an important role in development of early afterdepolarizations (EADs) and torsades de pointes (TdP). Secondary intracellular calcium (Cai) rise is associated with initiation of EADs. Objective To test whether inhibition of sarcoplasmic reticulum (SR) Ca2+ cycling suppresses secondary Cai rise and genesis of EADs. Methods Langendorff perfusion and dual voltage and Cai optical mapping were conducted in 10 rabbit hearts. Atrioventricular block (AVB) was created by radiofrequency ablation. After baseline studies, E4031, SR Ca2+ cycling inhibitors (ryanodine plus thapsigargin) and nifedipine were then administrated subsequently, and the protocols were repeated. Results At baseline, there was no spontaneous or pacing-induced TdP. After E4031 administration, action potential duration (APD) was significantly prolonged and the amplitude of secondary Cai rise was enhanced, and 7 (70%) rabbits developed spontaneous or pacing-induced TdP. In the presence of ryanodine plus thapsigargin, TdP inducibility was significantly reduced (2 hearts, 20%, p = 0.03). Although APD was significantly prolonged (from 298 ± 30 ms to 457 ± 75 ms at pacing cycle length of 1000 m, p = 0.007) by ryanodine plus thapsigargin, the secondary Cai rise was suppressed (from 8.8 ± 2.6% to 1.2 ± 0.9%, p = 0.02). Nifedipine inhibited TdP inducibility in all rabbit hearts. Conclusion In this AVB and long QT rabbit model, inhibition of SR Ca2+ cycyling reduces the inducibility of TdP. The mechanism might be suppression of secondary Cai rise and genesis of EADs. PMID:25875599

  15. Prolonged Tp-e Interval, Tp-e/QT Ratio and Tp-e/QTc Ratio in Patients with Type 2 Diabetes Mellitus

    PubMed Central

    Kiliçaslan, Fethi; Alis, Metin; Yiginer, Omer; Uzun, Mehmet

    2016-01-01

    Background Type 2 diabetes mellitus (T2DM) is associated with increased risk of malignant ventricular arrhythmias. Cardiac electrical inhomogeneity may be the leading cause of the increased arrhythmic risk in patients with T2DM. The peak and the end of the T wave (Tp-e) interval and associated Tp-e/QT ratio are promising measures of ventricular repolarization indicating transmural dispersion of repolarization. The aim of this study was to assess ventricular repolarization in patients with T2DM by using Tp-e interval, Tp-e/QT ratio and Tp-e/corrected QT interval (QTc) ratio. Methods Forty-three patients with T2DM and 43 healthy control subjects, matched by gender and age, were studied. All participants underwent electrocardiography (ECG) recording. PR, RR and QT intervals represents the ECG intervals. These are not abbreviations. In all literature these ECG intervals are written like in this text. Tp-e intervals were measured from 12-lead ECG. Rate QTc was calculated by using the Bazett's formula. Tp-e/QT ratio and Tp-e/QTc ratio were also calculated. Results Mean Tp-e interval was significantly prolonged in patients with T2DM compared to controls (79.4±10.3, 66.4±8.1 ms, respectively; P<0.001). We also found significantly higher values of Tp-e/QT ratio and Tp-e/QTc ratio in patients with diabetes than controls (0.21±0.03, 0.17±0.02 and 0.19±0.02, 0.16±0.02, respectively; P<0.001). There was no difference in terms of the other ECG parameters between the groups. Conclusion Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in patients with T2DM. We concluded that T2DM leads to augmentation of transmural dispersion of repolarization suggesting increased risk for ventricular arrhythmogenesis. PMID:26676332

  16. Drug-induced long QT syndrome: hERG K+ channel block and disruption of protein trafficking by fluoxetine and norfluoxetine

    PubMed Central

    Rajamani, S; Eckhardt, L L; Valdivia, C R; Klemens, C A; Gillman, B M; Anderson, C L; Holzem, K M; Delisle, B P; Anson, B D; Makielski, J C; January, C T

    2006-01-01

    Background and purpose: Fluoxetine (Prozac®) is a widely prescribed drug in adults and children, and it has an active metabolite, norfluoxetine, with a prolonged elimination time. Although uncommon, Prozac causes QT interval prolongation and arrhythmias; a patient who took an overdose of Prozac exhibited a prolonged QT interval (QTc 625 msec). We looked for possible mechanisms underlying this clinical finding by analysing the effects of fluoxetine and norfluoxetine on ion channels in vitro. Experimental approach: We studied the effects of fluoxetine and norfluoxetine on the electrophysiology and cellular trafficking of hERG K+ and SCN5A Na+ channels heterologously expressed in HEK293 cells. Key results: Voltage clamp analyses employing square pulse or ventricular action potential waveform protocols showed that fluoxetine and norfluoxetine caused direct, concentration-dependent, block of hERG current (IhERG). Biochemical studies showed that both compounds also caused concentration-dependent reductions in the trafficking of hERG channel protein into the cell surface membrane. Fluoxetine had no effect on SCN5A channel or HEK293 cell endogenous current. Mutations in the hERG channel drug binding domain reduced fluoxetine block of IhERG but did not alter fluoxetine's effect on hERG channel protein trafficking. Conclusions and implications: Our findings show that both fluoxetine and norfluoxetine at similar concentrations selectively reduce IhERG by two mechanisms, (1) direct channel block, and (2) indirectly by disrupting channel protein trafficking. These two effects are not mediated by a single drug binding site. Our findings add complexity to understanding the mechanisms that cause drug-induced long QT syndrome. PMID:16967046

  17. Long QT Syndrome Leading to Multiple Cardiac Arrests After Posaconazole Administration in an Immune-Compromised Patient with Sepsis: An Unusual Case Report.

    PubMed

    Panos, George; Velissaris, Dimitrios; Karamouzos, Vasilios; Matzaroglou, Charalampos; Tylianakis, Minos

    2016-01-01

    BACKGROUND We present the case of a septic patient with severe immunodeficiency, who developed QT interval prolongation followed by episodes of lethal cardiac arrhythmia. Cardiac events occurred after posaconazole administration, incriminating posaconazole use, alone or in combination with voriconazole, as the culpable agent. CASE REPORT A 26-year-old female patient underwent orthopedic surgery to remove ectopic calcifications in her left hip joint. On the first post-operative day she became septic due to a surgical wound infection. Despite being treated according to the therapeutic protocols for sepsis, no clinical improvement was noticed and further assessment revealed an underlying immunodeficiency. Considering the underlying immunodeficiency and to that point poor clinical response, an antifungal agent was added to the antibiotic regiment. Following discontinuation of multiple antifungal agents due to adverse effects, posaconazole was administered. Posaconazole oral intake was followed by episodes of bradycardia and QT interval prolongation. The patient suffered continuous incidents of cardiac arrest due to polymorphic ventricular tachycardia (torsades des pointes) that degenerated to lethal ventricular fibrillation. Posaconazole was immediately discontinued and a temporary pacemaker was installed. The patient finally recovered without any neurological deficit, and was discharged in a good clinical status. CONCLUSIONS Close cardiac monitoring is recommended in cases where posaconazole administration is combined with coexisting risk factors, as they may lead to severe ECG abnormalities and cardiac arrhythmias such as long QT interval syndrome and torsades de pointes. Posaconazole interactions with medications metabolized via the CYP3A4 pathway should be considered an additional risk factor for lethal cardiac incidents. PMID:27125217

  18. Long QT Syndrome

    MedlinePlus

    ... distinct electrical waves: P, Q, R, S, and T. EKG The image shows the standard setup for an EKG. In figure A, a normal heart rhythm recording ... B, a patient lies in a bed with EKG electrodes attached to his chest, upper arms, and ...

  19. Genetics Home Reference: otopalatodigital syndrome type 2

    MedlinePlus

    ... Conditions otopalatodigital syndrome type 2 otopalatodigital syndrome type 2 Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Otopalatodigital syndrome type 2 is a disorder involving abnormalities in skeletal development ...

  20. Genetics Home Reference: otopalatodigital syndrome type 1

    MedlinePlus

    ... Conditions otopalatodigital syndrome type 1 otopalatodigital syndrome type 1 Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Otopalatodigital syndrome type 1 is a disorder primarily involving abnormalities in skeletal ...

  1. Drug- and non-drug-associated QT interval prolongation

    PubMed Central

    van Noord, Charlotte; Eijgelsheim, Mark; Stricker, Bruno H Ch

    2010-01-01

    Sudden cardiac death is among the most common causes of cardiovascular death in developed countries. The majority of sudden cardiac deaths are caused by acute ventricular arrhythmia following repolarization disturbances. An important risk factor for repolarization disturbances is use of QT prolonging drugs, probably partly explained by gene–drug interactions. In this review, we will summarize QT interval physiology, known risk factors for QT prolongation, including drugs and the contribution of pharmacogenetics. The long QT syndrome can be congenital or acquired. The congenital long QT syndrome is caused by mutations in ion channel subunits or regulatory protein coding genes and is a rare monogenic disorder with a mendelian pattern of inheritance. Apart from that, several common genetic variants that are associated with QT interval duration have been identified. Acquired QT prolongation is more prevalent than the congenital form. Several risk factors have been identified with use of QT prolonging drugs as the most frequent cause. Most drugs that prolong the QT interval act by blocking hERG-encoded potassium channels, although some drugs mainly modify sodium channels. Both pharmacodynamic as well as pharmacokinetic mechanisms may be responsible for QT prolongation. Pharmacokinetic interactions often involve drugs that are metabolized by cytochrome P450 enzymes. Pharmacodynamic gene–drug interactions are due to genetic variants that potentiate the QT prolonging effect of drugs. QT prolongation, often due to use of QT prolonging drugs, is a major public health issue. Recently, common genetic variants associated with QT prolongation have been identified. Few pharmacogenetic studies have been performed to establish the genetic background of acquired QT prolongation but additional studies in this newly developing field are warranted. PMID:20642543

  2. A Framework of Knowledge Integration and Discovery for Supporting Pharmacogenomics Target Predication of Adverse Drug Events: A Case Study of Drug-Induced Long QT Syndrome

    PubMed Central

    Jiang, Guoqian; Wang, Chen; Zhu, Qian; Chute, Christopher G.

    2013-01-01

    Knowledge-driven text mining is becoming an important research area for identifying pharmacogenomics target genes. However, few of such studies have been focused on the pharmacogenomics targets of adverse drug events (ADEs). The objective of the present study is to build a framework of knowledge integration and discovery that aims to support pharmacogenomics target predication of ADEs. We integrate a semantically annotated literature corpus Semantic MEDLINE with a semantically coded ADE knowledgebase known as ADEpedia using a semantic web based framework. We developed a knowledge discovery approach combining a network analysis of a protein-protein interaction (PPI) network and a gene functional classification approach. We performed a case study of drug-induced long QT syndrome for demonstrating the usefulness of the framework in predicting potential pharmacogenomics targets of ADEs. PMID:24303306

  3. Mild Beckwith-Wiedemann and severe long-QT syndrome due to deletion of the imprinting center 2 on chromosome 11p.

    PubMed

    Gurrieri, Fiorella; Zollino, Marcella; Oliva, Antonio; Pascali, Vincenzo; Orteschi, Daniela; Pietrobono, Roberta; Camporeale, Antonella; Coll Vidal, Monica; Partemi, Sara; Brugada, Ramon; Bellocci, Fulvio; Neri, Giovanni

    2013-09-01

    We report on a young woman admitted to our Cardiology Unit because of an episode of cardiac arrest related to a long-QT syndrome (LQTS). This manifestation was part of a broader phenotype, which was recognized as a mild form of Beckwith-Wiedemann syndrome (BWS). Molecular analysis confirmed the diagnosis of BWS owing to a maternally inherited deletion of the centromeric imprinting center, or ICR2, an extremely rare genetic mechanism in BWS. The deletion interval (198 kb) also included exons 11-16 of the KCNQ1 gene, known to be responsible for LQTS at locus LQT1. No concomitant mutations were found in any other of the known LQT genes. The proposita's mother carries the same deletion in her paternal chromosome and shows manifestations of the Silver-Russell syndrome (SRS). This report describes the smallest BWS-causing ICR2 deletion and provides the first evidence that a paternal deletion of ICR2 leads to a SRS-like phenotype. In addition, our observation strongly suggests that in cases of LQTS due to mutation of the KCNQ1 gene (LQT1), an accurate clinical genetic evaluation should be done in order to program the most appropriate genetic tests. PMID:23511928

  4. Intravenous Administration of Apomorphine Does NOT Induce Long QT Syndrome: Experimental Evidence from In Vivo Canine Models.

    PubMed

    Watanabe, Yudai; Nakamura, Yuji; Cao, Xin; Ohara, Hiroshi; Yamazaki, Yukiko; Murayama, Norie; Sugiyama, Yosuke; Izumi-Nakaseko, Hiroko; Ando, Kentaro; Yamazaki, Hiroshi; Sugiyama, Atsushi

    2015-06-01

    Apomorphine is a non-selective dopamine D1/D2 receptor agonist, which has been used for patients with Parkinson's disease and reported to induce QT interval prolongation and cardiac arrest. To clarify their causal link, we assessed the cardiovascular and pharmacokinetic profile of apomorphine with the halothane-anaesthetized canine model (n = 4), whereas pro-arrhythmic potential of apomorphine was analysed with the chronic atrioventricular block canine model (n = 4). In the halothane-anaesthetized model, 0.01 mg/kg, i.v. of apomorphine hydrochloride over 10 min., providing about 10 times of its therapeutic concentration, increased the heart rate and ventricular contraction; 0.1 mg/kg over 10 min., providing about 100 times of the therapeutic, prolonged the ventricular effective refractory period; and 1 mg/kg over 10 min., providing about 1000 times of the therapeutic, decreased the ventricular contraction, mean blood pressure and cardiac output together with the intraventricular conduction delay and prolongation of the effective refractory period, whereas the left ventricular end-diastolic pressure, atrioventricular nodal conduction or ventricular repolarization were hardly affected. Meanwhile, in the atrioventricular block model, 1 mg/kg, i.v. of apomorphine hydrochloride over 10 min. neither prolonged the QT interval nor induced torsade de pointes. These results suggest that apomorphine may possess a wide margin of cardiovascular safety contrary to our expectations. PMID:25370785

  5. Measurement and interpretation of electrocardiographic QT intervals in murine hearts.

    PubMed

    Zhang, Yanmin; Wu, JingJing; King, James H; Huang, Christopher L-H; Fraser, James A

    2014-06-01

    Alterations in ECG QT intervals correlate with the risk of potentially fatal arrhythmias, for which transgenic murine hearts are becoming increasingly useful experimental models. However, QT intervals are poorly defined in murine ECGs. As a consequence, several different techniques have been used to measure murine QT intervals. The present work develops a consistent measure of the murine QT interval that correlates with changes in the duration of ventricular myocyte action potentials (APs). Volume-conducted ECGs were compared with simultaneously recorded APs, obtained using floating intracellular microelectrodes in Langendorff-perfused mouse hearts. QT intervals were measured from the onset of the QRS complex. The interval, Q-APR90, measured to the time at 90% AP recovery, was compared with two measures of the QT interval. QT1 was measured to the recovery of the ECG trace to the isoelectric baseline for entirely positive T-waves or to the trough of any negative T-wave undershoot. QT2-used extensively in previous studies-was measured to the return of any ECG trough to the isoelectric baseline. QT1, but not QT2, closely correlated with changes in Q-APR90. These findings were confirmed over a range of pacing rates, in low K(+) concentration solutions, and in Scn5a+/ΔKPQ hearts used to model human long QT syndrome. Application of this method in whole anesthetized mice similarly demonstrated a prolonged corrected QT (QTc) in Scn5a+/ΔKPQ hearts. We therefore describe a robust method for the determination of QT and QTc intervals that correlate with the duration of ventricular myocyte APs in murine hearts. PMID:24705556

  6. Electrocardiogram in Andersen-Tawil Syndrome. New Electrocardiographic Criteria for Diagnosis of Type-1 Andersen-Tawil Syndrome

    PubMed Central

    Kukla, Piotr; Biernacka, Elżbieta K; Baranchuk, Adrian; Jastrzębski, Marek; Jagodzińska, Michalina

    2014-01-01

    Andersen - Tawil syndrome (ATS) is an autosomal - dominant or sporadic disorder characterized by ventricular arrhythmias, periodic paralysis, and distinctive facial and skeletal dysmorphism. Mutations in KCNJ2, which encodes the α-subunit of the potassium channel Kir2.1, were identified in patients with ATS. This genotype has been designated as type-1 ATS (ATS1). KCNJ2 mutations are detectable in up to 60 % of patients with ATS. Cardiac manifestations of ATS include frequent premature ventricular contractions (PVC), Q-U interval prolongation, prominent U-waves, and a special type of polymorphic ventricular tachycardia (PMVT) called bidirectional ventricular tachycardia (BiVT). The presence of frequent PVCs at rest are helpful in distinguishing ATS from typical catecholaminergic polymorphic ventricular tachycardia (CPVT). In typical CPVT, rapid PMVT and BiVT usually manifest during or after exercising. Additionally, CPVT or torsade de pointes in LQTS are faster, very symptomatic causing syncope or often deteriorate into VF resulting in sudden cardiac death. PVCs at rest are quite frequent in ATS1 patients, however, in LQTS patients, PVCs and asymptomatic VT are uncommon which also contributes to differentiating them. The article describes the new electrocardiographic criteria proposed for diagnosis of type-1 Andersen-Tawil syndrome. A differential diagnosis between Andersen-Tawil syndrome, the catecholamine polymorphic ventiruclar tachycardia and long QT syndrome is depicted. Special attention is paid on the repolarization abnormalities, QT interval and the pathologic U wave. In this article, we aim to provide five new electrocardiographic clues for the diagnosis of ATS1. PMID:24827800

  7. Electrocardiographic screening for hypertrophic cardiomyopathy and long QT syndrome: the drivers of cost-effectiveness for the prevention of sudden cardiac death.

    PubMed

    Anderson, Brett R; McElligott, Sean; Polsky, Daniel; Vetter, Victoria L

    2014-02-01

    It is universally recognized that the prevention of sudden cardiac death (SCD) in youth is an important public health initiative. The best approach remains uncertain. Many European and Asian countries support the use of electrocardiograms (ECGs). In the United States, this is highly controversial. Many debate its cost-effectiveness. We designed a comprehensive economic model of two of the most prevalent causes of SCD identifiable by ECG, hypertrophic cardiomyopathy (HCM) and long QT syndrome (LQTS), to determine the drivers of uncertainty in the estimate of cost-effectiveness. We compared the cost-effectiveness of screening with history and physical examination (H&P) plus ECG to the current United States standard, H&P alone, for the detection and treatment of HCM and LQTS. We used a Markov model on a theoretical cohort of healthy 12-year-olds over a 70-year time horizon from a societal perspective, employing extensive univariable and probabilistic sensitivity analyses, to determine drivers of costs and effectiveness. The incremental cost-effectiveness of adding ECGs to H&Ps was $41,400/life-year saved. The model was highly sensitive to the effect of identification and treatment of previously undiagnosed individuals with HCM; however, it was insensitive to many variables commonly assumed to be significant, including the costs of ECGs, echocardiograms, and genetic testing, as well as the sensitivity and specificity of ECGs. No LQTS-related parameters were significant. This study suggests that the key to determining the cost-effectiveness of ECG screening in the United States lies in developing a better understanding of disease progression in the previously undiagnosed HCM population. PMID:24005901

  8. Nicorandil normalizes prolonged repolarisation in the first transgenic rabbit model with Long-QT syndrome 1 both in vitro and in vivo

    PubMed Central

    Biermann, Jürgen; Wu, Kezhong; Odening, Katja E.; Asbach, Stefan; Koren, Gideon; Peng, Xuwen; Zehender, Manfred; Bode, Christoph; Brunner, Michael

    2010-01-01

    Transgenic rabbits expressing loss-of-function pore mutants of the human gene KCNQ1 (KvLQT1-Y315S) have a Long QT-Syndrome 1 (LQT1) phenotype. We evaluated for the first time the effect of nicorandil, an opener of ATP-sensitive potassium channels, and of isoproterenol on cardiac action potential duration and heart rate dependent dispersion of repolarisation in transgenic LQT1 rabbits. In vivo LQT1 and littermate control were subjected to transvenous electrophysiological studies; in vitro monophasic action potentials were recorded from explanted Langendorff-perfused hearts. In vivo ventricular effective refractory periods (VERP) at the right ventricular base were significantly prolonged in LQT1 as compared to littermate control, resulting in a more pronounced VERP dispersion in LQT1. This difference in VERP dispersion between LQT1 and littermate control disappeared after infusion of nicorandil. In vitro, mean action potential durations (APD75 and APD90) of LQT1 were significantly prolonged compared to littermate control at baseline. Nicorandil decreased APD75 and APD90 in LQT1 and littermate control at all stimulated heart rates. After adding nicorandil, the APD90 at all hearts rates and the APD75 at high heart rates were no longer different. Dispersion of repolarisation (ΔAPD75 and ΔAPD90) was heart rate dependently decreased after nicorandil at all tested stimulation cycle lengths only in LQT1. We demonstrated phenotypic differences of LQT1 and littermate control in vivo and in vitro. Nicorandil 20 μmol/l improved repolarisation abnormalities and heterogeneities in transgenic LQT1 rabbits. PMID:20959120

  9. Atrial and ventricular lead insulation defects with resulting inappropriate shocks and end-of-life of the ICD pulse generator in a young bodybuilder with congenital long-QT-syndrome.

    PubMed

    Diez, Claudius; Hofmann, Hans-Stefan; Börgermann, Jochen

    2009-01-01

    We report on a 19-year-old male with a congenital Long-QT syndrome who was admitted to our hospital because of insulation defects of both atrial and ventricular ICD leads resulting in inappropriate delivered shocks and a non-responding pulse generator during telemetrical evaluation. The insulation defects led to multiple arc marks within the ICD pocket and there was a short circuit between denuded leads and the electrically active pulse generator. The high current flow generated sufficient heat to damage several circuits of the generator. A new ICD system was implanted successfully and the postoperative course has been remained uneventful for almost 6 years. PMID:18776999

  10. Mucopolysaccharidosis type II, Hunter's syndrome.

    PubMed

    Tylki-Szymańska, Anna

    2014-09-01

    Hunter syndrome is caused by deficiency of the lysososmal enzyme iduronate-2-sulphatase that cleaves O-linked sulphate moieties from dermatan sulphate and heparan sulphate and leads to accumulation of GAGs. The disease is a X-linked condition affecting males and rarely females, clinically divided into severe (2/3) and attenuated types. Children with severe form, diagnosed at 12-36 months, have coarse facial feature, short stature, joint stiffness, short neck, broad chest, large head circumference, watery diarrhea, skeletal changes, progressive and profound mental retardation, retinal degeneration' hearing loss, cardiomyopathy, valvular involvement, with progressive thickening and stiffening of the valve leaflets leading to mitral and aortic regurgitation and stenosis . Recurrent and prolonged rhinitis with persistent nasal discharge are the first symptoms of airway disease that manifests itself as noisy breathing and later sleep apnea. Some patients develop ivory-colored skin lesions on the upper back and sides of the upper arms, pathogenomic of Hunter syndrome. The scalp hair becomes coarse, straight and bristly. Inguinal and umbilical hernias occur caused by the disturbed structure of connective tissue and increased liver and spleen volume. Patients with attenuated form have normal intelligence and a milder phenotype. Physical features diagnosed later are similar but less pronounced but progress to severe disease. Sceening is by quantitative assessment of urinary GAGs excretion. Qualitative assessment of GAG by electrophoresis can distinguish the type of mucopolysaccharidosis. Definitive diagnosis is based on enzyme activity assay in leukocytes, fibroblasts or plasma. Molecular testing is recommended mainly for genetic counseling and carrier detection. Limited experience of Haematopoietic stem cell therapy in MPS II showed progressive neurodegeneration. Recombinant 125 Idursulfase, is indicated for long-term treatment. The response appears to depend on the

  11. Genetics Home Reference: autoimmune polyglandular syndrome, type 1

    MedlinePlus

    ... polyglandular syndrome, type 1 autoimmune polyglandular syndrome, type 1 Enable Javascript to view the expand/collapse boxes. ... All Close All Description Autoimmune polyglandular syndrome, type 1 is an inherited condition that affects many of ...

  12. Living with Long QT Syndrome

    MedlinePlus

    ... or go into cardiac arrest. Tell them to call 9–1–1 right away if you faint. Consider asking a family member and/or coworker to learn cardiopulmonary resuscitation (CPR) in case your heart stops beating. You also may want to keep an automated external defibrillator (AED) with you at home or ...

  13. Kenny-Caffey syndrome type 1

    PubMed Central

    El Jabbour, Tony; Aboursheid, Tarek; Keifo, Mohammad Baraa; Maksoud, Ismael; Alasmar, Diana

    2014-01-01

    Kenny-Caffey syndrome type 1 is a rare hereditary skeletal disorder. We present here a documented case of a 7-month-old girl with the characteristic symptoms of growth retardation, dysmorphic features, and hypoparathyroidism. PMID:24982829

  14. Sinus bradycardia, junctional rhythm, and low-rate atrial fibrillation in Short QT syndrome during 20 years of follow-up: three faces of the same genetic problem.

    PubMed

    Righi, Daniela; Silvetti, Massimo S; Drago, Fabrizio

    2016-03-01

    We describe the case of an asymptomatic girl with sinus bradycardia and short QT interval at birth, junctional bradycardia in infancy requiring single-chamber pacemaker, atrial fibrillation in adolescence, and V141M mutation in the KCNQ1 gene. Atrial fibrillation recurred and became unresponsive to electrical or anti-arrhythmic therapy. During 20 years of follow-up, a progressive evolution from sinus node dysfunction to low-rate atrial fibrillation was observed. PMID:26279191

  15. hERG1a N-terminal eag domain-containing polypeptides regulate homomeric hERG1b and heteromeric hERG1a/hERG1b channels: a possible mechanism for long QT syndrome.

    PubMed

    Trudeau, Matthew C; Leung, Lisa M; Roti, Elon Roti; Robertson, Gail A

    2011-12-01

    Human ether-á-go-go-related gene (hERG) potassium channels are critical for cardiac action potential repolarization. Cardiac hERG channels comprise two primary isoforms: hERG1a, which has a regulatory N-terminal Per-Arnt-Sim (PAS) domain, and hERG1b, which does not. Isolated, PAS-containing hERG1a N-terminal regions (NTRs) directly regulate NTR-deleted hERG1a channels; however, it is unclear whether hERG1b isoforms contain sufficient machinery to support regulation by hERG1a NTRs. To test this, we constructed a series of PAS domain-containing hERG1a NTRs (encoding amino acids 1-181, 1-228, 1-319, and 1-365). The NTRs were also predicted to form from truncation mutations that were linked to type 2 long QT syndrome (LQTS), a cardiac arrhythmia disorder associated with mutations in the hERG gene. All of the hERG1a NTRs markedly regulated heteromeric hERG1a/hERG1b channels and homomeric hERG1b channels by decreasing the magnitude of the current-voltage relationship and slowing the kinetics of channel closing (deactivation). In contrast, NTRs did not measurably regulate hERG1a channels. A short NTR (encoding amino acids 1-135) composed primarily of the PAS domain was sufficient to regulate hERG1b. These results suggest that isolated hERG1a NTRs directly interact with hERG1b subunits. Our results demonstrate that deactivation is faster in hERG1a/hERG1b channels compared to hERG1a channels because of fewer PAS domains, not because of an inhibitory effect of the unique hERG1b NTR. A decrease in outward current density of hERG1a/hERG1b channels by hERG1a NTRs may be a mechanism for LQTS. PMID:22124116

  16. Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization

    PubMed Central

    Arking, Dan E.; Pulit, Sara L.; Crotti, Lia; van der Harst, Pim; Munroe, Patricia B.; Koopmann, Tamara T.; Sotoodehnia, Nona; Rossin, Elizabeth J.; Morley, Michael; Wang, Xinchen; Johnson, Andrew D.; Lundby, Alicia; Gudbjartsson, Daníel F.; Noseworthy, Peter A.; Eijgelsheim, Mark; Bradford, Yuki; Tarasov, Kirill V.; Dörr, Marcus; Müller-Nurasyid, Martina; Lahtinen, Annukka M.; Nolte, Ilja M.; Smith, Albert Vernon; Bis, Joshua C.; Isaacs, Aaron; Newhouse, Stephen J.; Evans, Daniel S.; Post, Wendy S.; Waggott, Daryl; Lyytikäinen, Leo-Pekka; Hicks, Andrew A.; Eisele, Lewin; Ellinghaus, David; Hayward, Caroline; Navarro, Pau; Ulivi, Sheila; Tanaka, Toshiko; Tester, David J.; Chatel, Stéphanie; Gustafsson, Stefan; Kumari, Meena; Morris, Richard W.; Naluai, Åsa T.; Padmanabhan, Sandosh; Kluttig, Alexander; Strohmer, Bernhard; Panayiotou, Andrie G.; Torres, Maria; Knoflach, Michael; Hubacek, Jaroslav A.; Slowikowski, Kamil; Raychaudhuri, Soumya; Kumar, Runjun D.; Harris, Tamara B.; Launer, Lenore J.; Shuldiner, Alan R.; Alonso, Alvaro; Bader, Joel S.; Ehret, Georg; Huang, Hailiang; Kao, W.H. Linda; Strait, James B.; Macfarlane, Peter W.; Brown, Morris; Caulfield, Mark J.; Samani, Nilesh J.; Kronenberg, Florian; Willeit, Johann; Smith, J. Gustav; Greiser, Karin H.; zu Schwabedissen, Henriette Meyer; Werdan, Karl; Carella, Massimo; Zelante, Leopoldo; Heckbert, Susan R.; Psaty, Bruce M.; Rotter, Jerome I.; Kolcic, Ivana; Polašek, Ozren; Wright, Alan F.; Griffin, Maura; Daly, Mark J.; Arnar, David O.; Hólm, Hilma; Thorsteinsdottir, Unnur; Denny, Joshua C.; Roden, Dan M.; Zuvich, Rebecca L.; Emilsson, Valur; Plump, Andrew S.; Larson, Martin G.; O'Donnell, Christopher J.; Yin, Xiaoyan; Bobbo, Marco; D'Adamo, Adamo P.; Iorio, Annamaria; Sinagra, Gianfranco; Carracedo, Angel; Cummings, Steven R.; Nalls, Michael A.; Jula, Antti; Kontula, Kimmo K.; Marjamaa, Annukka; Oikarinen, Lasse; Perola, Markus; Porthan, Kimmo; Erbel, Raimund; Hoffmann, Per; Jöckel, Karl-Heinz; Kälsch, Hagen; Nöthen, Markus M.; consortium, HRGEN; den Hoed, Marcel; Loos, Ruth J.F.; Thelle, Dag S.; Gieger, Christian; Meitinger, Thomas; Perz, Siegfried; Peters, Annette; Prucha, Hanna; Sinner, Moritz F.; Waldenberger, Melanie; de Boer, Rudolf A.; Franke, Lude; van der Vleuten, Pieter A.; Beckmann, Britt Maria; Martens, Eimo; Bardai, Abdennasser; Hofman, Nynke; Wilde, Arthur A.M.; Behr, Elijah R.; Dalageorgou, Chrysoula; Giudicessi, John R.; Medeiros-Domingo, Argelia; Barc, Julien; Kyndt, Florence; Probst, Vincent; Ghidoni, Alice; Insolia, Roberto; Hamilton, Robert M.; Scherer, Stephen W.; Brandimarto, Jeffrey; Margulies, Kenneth; Moravec, Christine E.; Fabiola Del, Greco M.; Fuchsberger, Christian; O'Connell, Jeffrey R.; Lee, Wai K.; Watt, Graham C.M.; Campbell, Harry; Wild, Sarah H.; El Mokhtari, Nour E.; Frey, Norbert; Asselbergs, Folkert W.; Leach, Irene Mateo; Navis, Gerjan; van den Berg, Maarten P.; van Veldhuisen, Dirk J.; Kellis, Manolis; Krijthe, Bouwe P.; Franco, Oscar H.; Hofman, Albert; Kors, Jan A.; Uitterlinden, André G.; Witteman, Jacqueline C.M.; Kedenko, Lyudmyla; Lamina, Claudia; Oostra, Ben A.; Abecasis, Gonçalo R.; Lakatta, Edward G.; Mulas, Antonella; Orrú, Marco; Schlessinger, David; Uda, Manuela; Markus, Marcello R.P.; Völker, Uwe; Snieder, Harold; Spector, Timothy D.; Ärnlöv, Johan; Lind, Lars; Sundström, Johan; Syvänen, Ann-Christine; Kivimaki, Mika; Kähönen, Mika; Mononen, Nina; Raitakari, Olli T.; Viikari, Jorma S.; Adamkova, Vera; Kiechl, Stefan; Brion, Maria; Nicolaides, Andrew N.; Paulweber, Bernhard; Haerting, Johannes; Dominiczak, Anna F.; Nyberg, Fredrik; Whincup, Peter H.; Hingorani, Aroon; Schott, Jean-Jacques; Bezzina, Connie R.; Ingelsson, Erik; Ferrucci, Luigi; Gasparini, Paolo; Wilson, James F.; Rudan, Igor; Franke, Andre; Mühleisen, Thomas W.; Pramstaller, Peter P.; Lehtimäki, Terho J.; Paterson, Andrew D.; Parsa, Afshin; Liu, Yongmei; van Duijn, Cornelia; Siscovick, David S.; Gudnason, Vilmundur; Jamshidi, Yalda; Salomaa, Veikko; Felix, Stephan B.; Sanna, Serena; Ritchie, Marylyn D.; Stricker, Bruno H.; Stefansson, Kari; Boyer, Laurie A.; Cappola, Thomas P.; Olsen, Jesper V.; Lage, Kasper; Schwartz, Peter J.; Kääb, Stefan; Chakravarti, Aravinda; Ackerman, Michael J.; Pfeufer, Arne; de Bakker, Paul I.W.; Newton-Cheh, Christopher

    2014-01-01

    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal Mendelian Long QT Syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals we identified 35 common variant QT interval loci, that collectively explain ∼8-10% of QT variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 novel QT loci in 298 unrelated LQTS probands identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode for proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies novel candidate genes for ventricular arrhythmias, LQTS,and SCD. PMID:24952745

  17. Fluconazole-Induced Type 1 Kounis Syndrome.

    PubMed

    Singh Mahal, Hardeep

    2016-01-01

    The administration of fluconazole is commonly used in both inpatient and outpatient settings for the management of candidiasis infection. Although it is associated with a relatively safe side effect profile, some patients experience adverse effects associated with increased morbidity. We describe 1 such patient, a 42-year-old woman with a history of severe eczema who developed fluconazole-induced type 1 Kounis syndrome. Review of literature indicates that this as the first case reported of fluconazole-induced type 1 Kounis syndrome. PMID:26938747

  18. Rare case of orofaciodigital syndrome type I

    PubMed Central

    Singh, Abhishek Bahadur; Girhotra, Manish; Goel, Medha; Bhatia, Shilpee

    2013-01-01

    Orofaciodigital syndrome (OFDS) is a group of congenital anomalies which affects the face, oral structures and digits. There are nine subtypes with different modes of inheritance. OFDS type I is an X-linked dominant trait with lethality in the vast majority of affected males. We report a case of OFDS type I in an Indian girl at the age of seven who had most of the typical features of OFDS type I and nephrocalcinosis. PMID:23417374

  19. QT dispersion in adult hypertensives.

    PubMed Central

    Sani, Isa Muhammad; Solomon, Danbauchi Sulei; Imhogene, Oyati Albert; Ahmad, Alhassan Muhammad; Bala, Garko Sani

    2006-01-01

    Increased QT dispersion is associated with sudden cardiac death in congestive cardiac failure, hypertrophic cardiomyopathy and following myocardial infarction. Patients with hypertension--in particular, those with left ventricular hypertrophy (LVH)--are also at greater risk of sudden cardiac death. We examined whether QT dispersion, which is easily obtained from a routine ECG, correlates with LVH. One-hundred untreated patients with systemic hypertension and 78 normotensives had QT dispersion measured manually from a surface 12-lead electrocardiogram and two-dimensional echocardiography performed to measure interventricular septal thickness, posterior wall thickness and left ventricular internal diameter. Office blood pressure was also recorded. Multivariate analysis demonstrated significant relationships between QT dispersion and office systolic blood pressure, and left ventricular mass index. Manual measurement of QT dispersion might be a simple, noninvasive screening procedure to identify those hypertensives at greatest risk of sudden cardiac death in a third-world country. PMID:16623077

  20. Pronounced Effects of HERG-Blockers E-4031 and Erythromycin on APD, Spatial APD Dispersion and Triangulation in Transgenic Long-QT Type 1 Rabbits

    PubMed Central

    Franke, Gerlind; Perez Feliz, Stefanie; Hartmann, Maximilian; Koren, Gideon; Zehender, Manfred; Bode, Christoph; Brunner, Michael; Odening, Katja E.

    2014-01-01

    Background Prolongation of action potential duration (APD), increased spatial APD dispersion, and triangulation are major factors promoting drug-induced ventricular arrhythmia. Preclinical identification of HERG/IKr-blocking drugs and their pro-arrhythmic potential, however, remains a challenge. We hypothesize that transgenic long-QT type 1 (LQT1) rabbits lacking repolarizing IKs current may help to sensitively detect HERG/IKr-blocking properties of drugs. Methods Hearts of adult female transgenic LQT1 and wild type littermate control (LMC) rabbits were Langendorff-perfused with increasing concentrations of HERG/IKr-blockers E-4031 (0.001–0.1 µM, n = 9/7) or erythromycin (1–300 µM, n = 9/7) and APD, APD dispersion, and triangulation were analyzed. Results At baseline, APD was longer in LQT1 than in LMC rabbits in LV apex and RV mid. Erythromycin and E-4031 prolonged APD in LQT1 and LMC rabbits in all positions. However, erythromycin-induced percentaged APD prolongation related to baseline (%APD) was more pronounced in LQT1 at LV base-lateral and RV mid positions (100 µM, LQT1, +40.6±9.7% vs. LMC, +24.1±10.0%, p<0.05) and E-4031-induced %APD prolongation was more pronounced in LQT1 at LV base-lateral (0.01 µM, LQT1, +29.6±10.6% vs. LMC, +19.1±3.8%, p<0.05) and LV base-septal positions. Moreover, erythromycin significantly increased spatial APD dispersion only in LQT1 and increased triangulation only in LQT1 in LV base-septal and RV mid positions. Similarly, E-4031 increased triangulation only in LQT1 in LV apex and base-septal positions. Conclusions E-4031 and erythromycin prolonged APD and increased triangulation more pronouncedly in LQT1 than in LMC rabbits. Moreover, erythromycin increased APD dispersion only in LQT1, indicating that transgenic LQT1 rabbits could serve as sensitive model to detect HERG/IKr-blocking properties of drugs. PMID:25244401

  1. [Waardenburg syndrome type I: case report].

    PubMed

    Silva, Patricia Capua Vieira da; Rangel, Paula; Couto Jr, Abelardo

    2011-01-01

    Waardenburg syndrome (WS) type I is a non-progressive auditory-pigmentary disorder comprising congenital sensorineural hearing loss and pigmentary disturbances of the iris, hair, and skin, along with dystopia canthorum (lateral displacement of the inner canthi). Affected individuals may have higher risk of: neural tube defects, cleft lip and palate, limb abnormalities, and Hirschsprung disease. The diagnosis is clinical and should be considered if the individual has two major or one major plus two minor criteria. PAX3 is the only known gene associated to the syndrome. Nevertheless, its use is mostly for genetic counseling. Regarding different diagnosis, we may list: other causes of non-progressive auditory-pigmentary disorder comprising congenital sensorineural hearing loss, other types of Waardenburg syndrome, piebaldism, albinism, vitiligo and Teitz syndrome. This paper presents a case of an eleven year old boy with deafness and ophthalmologic alterations, based on his files and exams. It reinforced the importance of the ophthalmologist contributing for the diagnosis of this rare systemic disease, as it includes some ophthalmologic alterations. We remind that the early diagnosis allows adequate stimulation for the hearing loss, as well as preventive measures in case of pregnant women affected by genetic counseling. PMID:21915450

  2. Antimicrobial agents-associated with QT interval prolongation.

    PubMed

    Bril, Fernando; Gonzalez, Claudio Daniel; Di Girolamo, Guillermo

    2010-01-01

    QT interval prolongation is one of the most important causes of withdrawal of drugs from the market, due to its association with Torsades de Pointes (TdP), a potentially fatal arrhythmia. Although many antimicrobial drugs are capable of inducing this type of arrhythmia, the importance of this effect is usually underestimated. Macrolides, quinolones, azoles, pentamidine, protease inhibitors, antimalarial drugs and cotrimoxazole are the anti-infective agents more frequently associated with this adverse effect. Despite the fact that the risk of QT prolongation and TdP under single antimicrobial therapy is low, these drugs are so extensively used that sporadic cases of this arrhythmia are reported. Moreover, antimicrobial drugs are susceptible to pharmacokinetic and pharmacodynamic interactions with other drugs, which may increase the risk of this arrhythmia. Therefore, physicians must be familiar with not only the antimicrobial drugs capable of producing QT interval prolongation, but also their potential interactions. In addition, patient's specific risk factors of prolonging QT interval or producing TdP must be taken into account. This article reviews the role of anti-infective drugs in QT prolongation, focusing on QT prolongation mechanisms, potential drug interactions, and patients' predisposing factors to this arrhythmia. PMID:20210724

  3. Waardenburg Syndrome type 1: A case report.

    PubMed

    Demirci, Gulsen Tukenmez; Atıs, Guldehan; Altunay, Ilknur Kıvanc

    2011-01-01

    Waardenburg Syndrome (WS) is a rare hereditary disorder that is characterized by the clinical manifestations of oculocutaneous anomalies of pigmentation, congenital deafness, dystopia canthorum, and broad nasal root. It demonstrates both genetically and clinically heterogenous characteristics. In this article, we report an 11-month-old boy with WS1, one of four clinicat types of WS. He exhibited white forelock, hypopigmented macules and patches, heterochromia irides, and dystopia canthorum. PMID:22136859

  4. QT interval in anorexia nervosa.

    PubMed Central

    Cooke, R A; Chambers, J B; Singh, R; Todd, G J; Smeeton, N C; Treasure, J; Treasure, T

    1994-01-01

    OBJECTIVES--To determine the incidence of a long QT interval as a marker for sudden death in patients with anorexia nervosa and to assess the effect of refeeding. To define a long QT interval by linear regression analysis and estimation of the upper limit of the confidence interval (95% CI) and to compare this with the commonly used Bazett rate correction formula. DESIGN--Prospective case control study. SETTING--Tertiary referral unit for eating disorders. SUBJECTS--41 consecutive patients with anorexia nervosa admitted over an 18 month period. 28 age and sex matched normal controls. MAIN OUTCOME MEASURES--maximum QT interval measured on 12 lead electrocardiograms. RESULTS--43.6% of the variability in the QT interval was explained by heart rate alone (p < 0.00001) and group analysis contributed a further 5.9% (p = 0.004). In 6 (15%) patients the QT interval was above the upper limit of the 95% CI for the prediction based on the control equation (NS). Two patients died suddenly; both had a QT interval at or above the upper limit of the 95% CI. In patients who reached their target weights the QT interval was significantly shorter (median 9.8 ms; p = 0.04) relative to the upper limit of the 60% CI of the control regression line, which best discriminated between patients and controls. The median Bazett rate corrected QT interval (QTc) in patients and controls was 435 v 405 ms.s-1/2 (p = 0.0004), and before and after refeeding it was 435 v 432 ms.s1/2 (NS). In 14(34%) patients and three (11%) controls the QTc was > 440 ms.s-1/2 (p = 0.053). CONCLUSIONS--The QT interval was longer in patients with anorexia nervosa than in age and sex matched controls, and there was a significant tendency to reversion to normal after refeeding. The Bazett rate correction formula overestimated the number of patients with QT prolongation and also did not show an improvement with refeeding. PMID:8068473

  5. Congenital Nephrotic Syndrome – Finish Type

    PubMed Central

    Spahiu, Lidvana; Merovci, Besart; Jashari, Haki; Këpuska, Arbnore Batalli; Rugova, Blerta Elezi

    2016-01-01

    Introduction: Identification of the NPHS1 gene, which encodes nephrin, was followed by many studies demonstrating its mutation as a frequent cause of congenital nephrotic syndrome (CNS). While this gene is found in 98% of Finnish children with this syndrome, non-Finnish cases have lower level of incidence ranging from 39 to 80%. Case report: This report describes the clinical presentation of a two-week-old neonate who presented with periorbital and lower extremities edema, abdominal distention, heavy proteinuria, serum hypoproteinemia and failure to thrive. Genetic analysis revealed NHPS1 gene mutation leading to CNS-Finnish type diagnosis. Conclusion: Through this case we want to create awareness about diagnosis and treatment challenges in developing countries for rare congenital diseases. PMID:27594755

  6. Cardiorenal Syndrome Type 4: A Review

    PubMed Central

    Clementi, Anna; Virzì, Grazia Maria; Goh, Ching Yan; Cruz, Dinna N.; Granata, Antonio; Vescovo, Girogio; Ronco, Claudio

    2013-01-01

    There is a bidirectional and complex relationship between the heart and kidneys. This interaction is physical, chemical as well as biological and is also reflected in a strong connection between renal and cardiovascular diseases. Cardiorenal syndrome type 4 (CRS type 4) is characterized by primary chronic kidney disease (CKD) leading to an impairment of cardiac function, with ventricular hypertrophy, diastolic dysfunction, and/or increased risk of adverse cardiovascular events. The incidence of CKD is increasing, and CRS type 4 is becoming a major public health problem associated with a high morbidity and mortality. In this study, we briefly review the epidemiology and pathophysiology of CRS type 4, the role of biomarkers in its early identification, and its management. PMID:23946725

  7. Targeted therapy for hereditary cancer syndromes: neurofibromatosis type 1, neurofibromatosis type 2, and Gorlin syndrome.

    PubMed

    Agarwal, Rishi; Liebe, Sarah; Turski, Michelle L; Vidwans, Smruti J; Janku, Filip; Garrido-Laguna, Ignacio; Munoz, Javier; Schwab, Richard; Rodon, Jordi; Kurzrock, Razelle; Subbiah, Vivek

    2014-12-01

    Hereditary cancer syndromes are well known in the oncology community, typically affecting children, adolescents, and young adults and thereby resulting in great cumulative morbidity and mortality. These syndromes often lag behind their de novo counterparts in the development of approved novel treatment options due to their rarity in the general population. Recent work has allowed the identification of molecular aberrations and associated targeted therapies that may effectively treat these conditions. In this review, we seek to characterize some of the involved aberrations and associated targeted therapies for several germline malignancies, including neurofibromatosis types 1 and 2, and Gorlin syndrome. Though patients with hereditary cancer syndromes may be too rare to effectively include in large clinical trials, by understanding the pathophysiology of these diseases, clinicians can attain insights into the use of targeted therapies in their own practice when treating affected individuals. PMID:25549703

  8. Iatrogenic QT Abnormalities and Fatal Arrhythmias: Mechanisms and Clinical Significance

    PubMed Central

    Cubeddu, Luigi X

    2009-01-01

    Severe and occasionally fatal arrhythmias, commonly presenting as Torsade de Pointes [TdP] have been reported with Class III-antiarrhythmics, but also with non-antiarrhythmic drugs. Most cases result from an action on K+ channels encoded by the HERG gene responsible for the IKr repolarizing current, leading to a long QT and repolarization abnormalities. The hydrophobic central cavity of the HERG-K+ channels, allows a large number of structurally unrelated drugs to bind and cause direct channel inhibition. Some examples are dofetilide, quinidine, sotalol, erythromycin, grepafloxacin, cisapride, dolasetron, thioridazine, haloperidol, droperidol and pimozide. Other drugs achieve channel inhibition indirectly by impairing channel traffic from the endoplasmic reticulum to the cell membrane, decreasing channel membrane density (pentamidine, geldalamicin, arsenic trioxide, digoxin, and probucol). Whereas, ketoconazole, fluoxetine and norfluoxetine induce both direct channel inhibition and impaired channel trafficking. Congenital long QT syndrome, subclinical ion-channel mutations, subjects and relatives of subjects with previous history of drug-induced long QT or TdP, dual drug effects on cardiac repolarization [long QT plus increased QT dispersion], increased transmural dispersion of repolarization and T wave abnormalities, use of high doses, metabolism inhibitors and/or combinations of QT prolonging drugs, hypokalemia, structural cardiac disease, sympathomimetics, bradycardia, women and older age, have been shown to increase the risk for developing drug-induced TdP. Because most of these reactions are preventable, careful evaluation of risk factors and increased knowledge of drugs use associated with repolarization abnormalities is strongly recommended. Future genetic testing and development of practical and simple provocation tests are in route to prevent iatrogenic TdP. PMID:20676275

  9. Nephrocalcinosis as adult presentation of Bartter syndrome type II.

    PubMed

    Huang, L; Luiken, G P M; van Riemsdijk, I C; Petrij, F; Zandbergen, A A M; Dees, A

    2014-02-01

    Bartter syndrome consists a group of rare autosomal-recessive renal tubulopathies characterised by renal salt wasting, hypokalaemic metabolic alkalosis, hypercalciuria and hyperreninaemic hyperaldosteronism. It is classified into five types. Mutations in the KCNJ1 gene (classified as type II) usually cause the neonatal form of Bartter syndrome. We describe an adult patient with a homozygous KCNJ1 mutation resulting in a remarkably mild phenotype of neonatal type Bartter syndrome. PMID:24659592

  10. hERG channel function: beyond long QT

    PubMed Central

    Babcock, Joseph J; Li, Min

    2013-01-01

    To date, research on the human ether-a-go-go related gene (hERG) has focused on this potassium channel's role in cardiac repolarization and Long QT Syndrome (LQTS). However, growing evidence implicates hERG in a diversity of physiologic and pathological processes. Here we discuss these other functions of hERG, particularly their impact on diseases beyond cardiac arrhythmia. PMID:23459091

  11. Epidemiology of paediatric metabolic syndrome and type 2 diabetes mellitus.

    PubMed

    De Ferranti, Sarah D; Osganian, Stavroula K

    2007-12-01

    The epidemic in childhood obesity is a driving force behind the increase in paediatric metabolic syndrome, a collection of abnormalities that is associated in adults with increased risk for cardiovascular disease and type 2 diabetes mellitus. Although there is no clear consensus about the paediatric definition for metabolic syndrome, the prevalence of this syndrome is clearly rising. Children with metabolic syndrome are at increased risk for metabolic syndrome in adulthood. A late consequence of metabolic syndrome is type 2 diabetes, which increasingly affects adolescents. The rise in metabolic syndrome and type 2 diabetes in children is almost sure to lead to an increase in associated complications in young adulthood, including early cardiovascular disease. This epidemic will bear fruit in forthcoming decades, putting further stress on the healthcare system and probably leading to increased morbidity and a shorter lifespan for future generations. PMID:18158698

  12. Autoimmune polyglandular syndrome type 3 with anorexia.

    PubMed

    Kahara, Toshio; Wakakuri, Hitomi; Takatsuji, Juri; Motoo, Iori; Shima, Kosuke R; Ishikura, Kazuhide; Usuda, Rika; Noda, Yatsugi

    2012-01-01

    A 71-year-old man with diabetes mellitus visited our hospital with complaints of anorexia and weight loss (12 kg/3 months). He had megaloblastic anemia, cobalamin level was low, and autoantibody to intrinsic factor was positive. He was treated with intramuscular cyanocobalamin, and he was able to consume meals. GAD autoantibody and ICA were positive, and he was diagnosed with slowly progressive type 1 diabetes mellitus (SPIDDM). Thyroid autoantibodies were positive. According to these findings, he was diagnosed with autoimmune polyglandular syndrome type 3 with SPIDDM, pernicious anemia, and Hashimoto's thyroiditis. Extended periods of cobalamin deficiency can cause serious complications such as ataxia and dementia, and these complications may not be reversible if replacement therapy with cobalamin is delayed. Although type 1 diabetes mellitus with coexisting pernicious anemia is very rare in Japan, physicians should consider the possibility of pernicious anemia when patients with diabetes mellitus have cryptogenic anorexia with the finding of significant macrocytosis (MCV > 100 fL). PMID:23304573

  13. Histopathological types in adult nephrotic syndrome.

    PubMed

    Yusuf, Md Ghulam; Das, Bidhu Bhushan; Shaha, Amaresh Chandra; Hossain, Md Zakir

    2016-01-01

    In Bangladesh, there are very few studies about biopsy proven adult Nephrotic syndrome (NS) with histological types and their clinical findings. To determine the histological types of glomerulonephritis (GN) in adult NS and correlate them with the clinical presentations and biochemical parameters, we studied 100 biopsies in 87 patients who underwent ultrasonography- guided renal biopsy in Rangpur Medical College and Hospital from July 2010 to June 2012. The mean age of the patients was 32.8 ± 13.2 years; male was preponderance (72.4%) and most of the patients (67.8%) came from rural areas. Membranoproliferative GN (MPGN) was the most common underlying cause that was found in 32 (36.8%) patients followed by mesangial prolife- rative GN in 27 (31%) patients, membranous GN in 16 (18.4%) cases, minimal change disease in four (4.6%) patients, diffuse proliferative GN in four (4.6%) patients, focal segmental GN, and focal proliferative GN in two (2.4%) patients each. High proteinuria level was found in minimal change disease, which was 7.59 ± 0.24 g/24 h (mean ± standard deviation). The most common symptoms were oliguria (92%) and edema (86.2%) followed by hematuria (dark urine) (72.4%) and hypertension (35.6%). MPGN was the most common histological type of adult NS in Rangpur. PMID:27215253

  14. Waardenburg syndrome type 2: an orthodontic perspective.

    PubMed

    Şuhani, Raluca Diana; Şuhani, Mihai Flaviu; Muntean, Alexandrina; Mesaroş, Michaela Florica; Badea, Mîndra Eugenia

    2015-01-01

    Waardenburg syndrome is a rare form of neurocristopathy. It is a disorder in the development of neural crest cells, caused by an altered cellular migration during the embryonic phase. That alteration causes an association of different abnormalities such as pigmentary disturbances of the hair, iris, skin, stria vascularis of the cochlea, dystopia canthorum and sensorineural hearing loss. We report a case of a 14-year-old Romanian male, with a family history of Waardenburg syndrome (mother) and Usher syndrome (father - congenitally sensorineural hearing loss and retinal degeneration). The case particularities are: the correlation between malocclusion and Waardenburg syndrome due to hypoplastic alae nasi and also factors that produced hearing loss, which could be Waardenburg syndrome, Usher syndrome or the presence of the connexin 26 (W24X) gene mutation. PMID:26429191

  15. Cholesterol and Alzheimer Type Dementia among Adults with Down Syndrome

    ERIC Educational Resources Information Center

    Buckley, Frank

    2008-01-01

    This article reports a summary of research by Warren Zigman and colleagues investigating the link between cholesterol levels and Alzheimer type dementia among adults with Down syndrome. Warren Zigman and colleagues followed 123 adults with Down syndrome between May 1998 and April 2006. The participants were aged between 41 and 78 years at the…

  16. Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

    PubMed

    Arking, Dan E; Pulit, Sara L; Crotti, Lia; van der Harst, Pim; Munroe, Patricia B; Koopmann, Tamara T; Sotoodehnia, Nona; Rossin, Elizabeth J; Morley, Michael; Wang, Xinchen; Johnson, Andrew D; Lundby, Alicia; Gudbjartsson, Daníel F; Noseworthy, Peter A; Eijgelsheim, Mark; Bradford, Yuki; Tarasov, Kirill V; Dörr, Marcus; Müller-Nurasyid, Martina; Lahtinen, Annukka M; Nolte, Ilja M; Smith, Albert Vernon; Bis, Joshua C; Isaacs, Aaron; Newhouse, Stephen J; Evans, Daniel S; Post, Wendy S; Waggott, Daryl; Lyytikäinen, Leo-Pekka; Hicks, Andrew A; Eisele, Lewin; Ellinghaus, David; Hayward, Caroline; Navarro, Pau; Ulivi, Sheila; Tanaka, Toshiko; Tester, David J; Chatel, Stéphanie; Gustafsson, Stefan; Kumari, Meena; Morris, Richard W; Naluai, Åsa T; Padmanabhan, Sandosh; Kluttig, Alexander; Strohmer, Bernhard; Panayiotou, Andrie G; Torres, Maria; Knoflach, Michael; Hubacek, Jaroslav A; Slowikowski, Kamil; Raychaudhuri, Soumya; Kumar, Runjun D; Harris, Tamara B; Launer, Lenore J; Shuldiner, Alan R; Alonso, Alvaro; Bader, Joel S; Ehret, Georg; Huang, Hailiang; Kao, W H Linda; Strait, James B; Macfarlane, Peter W; Brown, Morris; Caulfield, Mark J; Samani, Nilesh J; Kronenberg, Florian; Willeit, Johann; Smith, J Gustav; Greiser, Karin H; Meyer Zu Schwabedissen, Henriette; Werdan, Karl; Carella, Massimo; Zelante, Leopoldo; Heckbert, Susan R; Psaty, Bruce M; Rotter, Jerome I; Kolcic, Ivana; Polašek, Ozren; Wright, Alan F; Griffin, Maura; Daly, Mark J; Arnar, David O; Hólm, Hilma; Thorsteinsdottir, Unnur; Denny, Joshua C; Roden, Dan M; Zuvich, Rebecca L; Emilsson, Valur; Plump, Andrew S; Larson, Martin G; O'Donnell, Christopher J; Yin, Xiaoyan; Bobbo, Marco; D'Adamo, Adamo P; Iorio, Annamaria; Sinagra, Gianfranco; Carracedo, Angel; Cummings, Steven R; Nalls, Michael A; Jula, Antti; Kontula, Kimmo K; Marjamaa, Annukka; Oikarinen, Lasse; Perola, Markus; Porthan, Kimmo; Erbel, Raimund; Hoffmann, Per; Jöckel, Karl-Heinz; Kälsch, Hagen; Nöthen, Markus M; den Hoed, Marcel; Loos, Ruth J F; Thelle, Dag S; Gieger, Christian; Meitinger, Thomas; Perz, Siegfried; Peters, Annette; Prucha, Hanna; Sinner, Moritz F; Waldenberger, Melanie; de Boer, Rudolf A; Franke, Lude; van der Vleuten, Pieter A; Beckmann, Britt Maria; Martens, Eimo; Bardai, Abdennasser; Hofman, Nynke; Wilde, Arthur A M; Behr, Elijah R; Dalageorgou, Chrysoula; Giudicessi, John R; Medeiros-Domingo, Argelia; Barc, Julien; Kyndt, Florence; Probst, Vincent; Ghidoni, Alice; Insolia, Roberto; Hamilton, Robert M; Scherer, Stephen W; Brandimarto, Jeffrey; Margulies, Kenneth; Moravec, Christine E; del Greco M, Fabiola; Fuchsberger, Christian; O'Connell, Jeffrey R; Lee, Wai K; Watt, Graham C M; Campbell, Harry; Wild, Sarah H; El Mokhtari, Nour E; Frey, Norbert; Asselbergs, Folkert W; Mateo Leach, Irene; Navis, Gerjan; van den Berg, Maarten P; van Veldhuisen, Dirk J; Kellis, Manolis; Krijthe, Bouwe P; Franco, Oscar H; Hofman, Albert; Kors, Jan A; Uitterlinden, André G; Witteman, Jacqueline C M; Kedenko, Lyudmyla; Lamina, Claudia; Oostra, Ben A; Abecasis, Gonçalo R; Lakatta, Edward G; Mulas, Antonella; Orrú, Marco; Schlessinger, David; Uda, Manuela; Markus, Marcello R P; Völker, Uwe; Snieder, Harold; Spector, Timothy D; Ärnlöv, Johan; Lind, Lars; Sundström, Johan; Syvänen, Ann-Christine; Kivimaki, Mika; Kähönen, Mika; Mononen, Nina; Raitakari, Olli T; Viikari, Jorma S; Adamkova, Vera; Kiechl, Stefan; Brion, Maria; Nicolaides, Andrew N; Paulweber, Bernhard; Haerting, Johannes; Dominiczak, Anna F; Nyberg, Fredrik; Whincup, Peter H; Hingorani, Aroon D; Schott, Jean-Jacques; Bezzina, Connie R; Ingelsson, Erik; Ferrucci, Luigi; Gasparini, Paolo; Wilson, James F; Rudan, Igor; Franke, Andre; Mühleisen, Thomas W; Pramstaller, Peter P; Lehtimäki, Terho J; Paterson, Andrew D; Parsa, Afshin; Liu, Yongmei; van Duijn, Cornelia M; Siscovick, David S; Gudnason, Vilmundur; Jamshidi, Yalda; Salomaa, Veikko; Felix, Stephan B; Sanna, Serena; Ritchie, Marylyn D; Stricker, Bruno H; Stefansson, Kari; Boyer, Laurie A; Cappola, Thomas P; Olsen, Jesper V; Lage, Kasper; Schwartz, Peter J; Kääb, Stefan; Chakravarti, Aravinda; Ackerman, Michael J; Pfeufer, Arne; de Bakker, Paul I W; Newton-Cheh, Christopher

    2014-08-01

    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD. PMID:24952745

  17. The risk for type B aortic dissection in Marfan syndrome.

    PubMed

    Setacci, C; Galzerano, G; Setacci, F; Mazzitelli, G; de Donato, G; Ricci, C

    2015-12-01

    Marfan syndrome is the most prevalent connective tissue disorder, with an autosomal dominant inheritance with variable penetrance. This paper aims to summarize epidemiology and treatment for type B dissection in Marfan patients. PMID:26350976

  18. Sudden cardiac arrest during anesthesia in a 30-month-old boy with syndactyly: a case of genetically proven Timothy syndrome.

    PubMed

    An, Hyo Soon; Choi, Eun Young; Kwon, Bo Sang; Kim, Gi Beom; Bae, Eun Jung; Noh, Chung Il; Choi, Jung Yun; Park, Sung Sup

    2013-05-01

    Timothy syndrome, long QT syndrome type 8, is highly malignant with ventricular tachyarrhythmia. A 30-month-old boy had sudden cardiac arrest during anesthesia induction before plastic surgery for bilateral cutaneous syndactyly. After successful resuscitation, prolonged QT interval (QTc, 0.58-0.60 sec) and T-wave alternans were found in his electrocardiogram. Starting β-blocker to prevent further tachycardia and collapse event, then there were no more arrhythmic events. The genes KCNQ1, KCNH2, KCNE1 and 2, and SCN5A were negative for long QT syndrome. The mutation p.Gly406Arg was confirmed in CACNA1C, which maintains L-type calcium channel depolarization in the heart and other systems. PMID:23678275

  19. Gait Strategy in Patients with Ehlers-Danlos Syndrome Hypermobility Type and Down Syndrome

    ERIC Educational Resources Information Center

    Rigoldi, Chiara; Galli, Manuela; Cimolin, Veronica; Camerota, Filippo; Celletti, Claudia; Tenore, Nunzio; Albertini, Giorgio

    2012-01-01

    People suffering from Ehlers-Danlos syndrome (EDS) hypermobility type present a severe ligament laxity that results in difficulties in muscle force transmission. The same condition is present in people suffering from Down syndrome (DS) even if their clumsy movements are due to cerebral and cognitive impairments. The aim of this study was to…

  20. Type VI Aplasia Cutis Congenita: Bart's Syndrome

    PubMed Central

    Kulalı, Ferit; Bas, Ahmet Yagmur; Kale, Yusuf; Celik, Istemi Han; Demirel, Nihal; Apaydın, Sema

    2015-01-01

    Bart's syndrome is characterized by aplasia cutis congenita and epidermolysis bullosa. We present the case of a newborn male who developed blisters on the mucous membranes and the skin following congenital localized absence of skin. Bart's syndrome (BS) is diagnosed clinically based on the disorder's unique signs and symptoms but histologic evaluation of the skin can help to confirm the final diagnosis. The patient was managed conservatively with topical antibacterial ointment and wet gauze dressing. Periodic follow-up examinations showed complete healing. We emphasized that it is important to use relatively simple methods for optimal healing without the need for complex surgical interventions. PMID:26609453

  1. Nevus comedonicus in oral-facial-digital syndrome type 1: a new finding or overlapping syndromes?

    PubMed

    Baker, Lauren A; Agim, Nnenna G

    2014-01-01

    We report a patient with oral-facial-digital syndrome type 1 (OFDS1) who exhibited features overlapping those of nevus comedonicus syndrome, an unusual presentation that may potentially represent a new variant of OFDS1. OFDS1 and nevus comedonicus syndrome represent two rare syndromes with numerous overlapping features that have yet to be described in relation to one another. The features present in our patient led us to propose the possibility of a new variant of OFDS1 in which nevus comedonicus represents a cutaneous manifestation of the syndrome. Knowledge of this potential relationship is important for identification and management of the syndromes' accompanying manifestations in affected patients and may offer further insight into crossroads of pathogenesis. PMID:24517846

  2. QT Dispersion after Thrombolytic Therapy

    PubMed Central

    Oni Heris, Saeed; Rahimi, Behzad; Faridaalaee, Gholamreza; Hajahmadi, Mojgan; Sayyadi, Hojjat; Naghipour, Bahman

    2014-01-01

    Background: QT dispersion (QTd) is equal to longer QTc minus shorter QTc measured by 12-lead electrocardiogram (ECG). QTd reflects inhomogeneity in repolarization of ventricular myocardium and because of easy and fast measurement of QTd, it can be used to predict high-risk patients for dysrhythmia after Acute Myocardial Infarction (AMI). Objectives: This study aimed to assess the effect of thrombolytic therapy on QTd before and 1 hour and 4 days after beginning of thrombolytic therapy. Patients and Methods: The patients with chest pain and ST Elevated Myocardial Infarction (STEMI) that underwent thrombolytic therapy were enrolled into this study. Streptokinase was the thrombolytic agent in all the patients. Standard 12-lead (ECG) was evaluated before beginning of thrombolytic therapy (QTd 1) and 1 hour (QTd2) and 4 days (QTd3) after thrombolytic therapy. First, ECG was magnified × 10 for exact calculation of QT and QTd. After all, the variables were compared using one–way analysis of variance (ANOVA). Besides, P ≤ 0.05 was considered as statistically significant. Results: This study was conducted on 160 patients. The results revealed no significant differences among QTd 1, QTd 2, and QTd 3 (P > 0.05). At inferior AMI, however, a significant difference was observed among QTd1, QTd2, and QTd3 (P = 0.031). Conclusions: Thrombolytic therapy had no significant effects on QTd. Thus, thrombolytic therapy does not increase the risk of arrhythmia. PMID:25614860

  3. Oral Contraceptive Use and the ECG: Evidence of an Adverse QT Effect on Corrected QT Interval

    PubMed Central

    Sedlak, Tara; Shufelt, Chrisandra; Iribarren, Carlos; Lyon, Liisa L; Merz, C. Noel Bairey

    2013-01-01

    Background A prolonged corrected QT (QTc) interval is a marker for an increased risk of sudden cardiac death. We evaluated the relationship between oral contraceptive (OC) use, type of OC, and QTc interval. Methods We identified 410,782 ECGs performed at Northern California Kaiser Permanente on female patients between 15–53 years from January, 1995 to June, 2008. QT was corrected for heart rate using log-linear regression. OC generation (first, second and third) was classified by increasing progestin androgenic potency, while the fourth generation was classified as anti-androgenic. Results Among 410,782 women, 8.4% were on OC. In multivariate analysis after correction for comorbidities, there was an independent shortening effect of OCs overall (slope = −0.5ms; SE = 0.12, p<0.0002). Users of first and second generation progestins had a significantly shorter QTc than non-users (p<0.0001), while users of fourth generation had a significantly longer QTc than non-users (slope = 3.6ms, SE = 0.35, p<0.0001). Conclusion Overall, OC use has a shortening effect on the QTc. Shorter QTc is seen with first and second generation OC while fourth generation OC use has a lengthening effect on the QTc. Careful examination of adverse event rates in fourth generation OC users is needed. PMID:23879279

  4. Burning mouth syndrome due to herpes simplex virus type 1.

    PubMed

    Nagel, Maria A; Choe, Alexander; Traktinskiy, Igor; Gilden, Don

    2015-01-01

    Burning mouth syndrome is characterised by chronic orofacial burning pain. No dental or medical cause has been found. We present a case of burning mouth syndrome of 6 months duration in a healthy 65-year-old woman, which was associated with high copy numbers of herpes simplex virus type 1 (HSV-1) DNA in the saliva. Her pain resolved completely after antiviral treatment with a corresponding absence of salivary HSV-1 DNA 4 weeks and 6 months later. PMID:25833911

  5. Cardio-renal syndrome type 5: epidemiology, pathophysiology, and treatment.

    PubMed

    Soni, Sachin S; Ronco, Claudio; Pophale, Rupesh; Bhansali, Ashish S; Nagarik, Amit P; Barnela, Shriganesh R; Saboo, Sonali S; Raman, Anuradha

    2012-01-01

    The cardio-renal syndromes (CRS) recently were defined systematically as disorders of the heart or kidney whereby dysfunction of one organ leads to dysfunction of another. Five types of CRS are defined. The first four types describe acute or chronic cardio-renal or renocardiac syndromes. Type 5 CRS refers to secondary cardio-renal syndrome or cardio-renal involvement in systemic conditions. It is a clinical and pathophysiological entity to describe the concomitant presence of renal and cardiovascular dysfunction. Type 5 CRS can be acute or chronic and it does not strictly satisfy the definition of CRS. However, it encompasses many conditions in which combined heart and kidney dysfunction is observed. Because this entity has been described only recently there is limited information about the epidemiology, clinical course, and treatment of this condition. PMID:22365162

  6. Risk assessment of drug-induced QT prolongation

    PubMed Central

    Isbister, Geoffrey K

    2015-01-01

    SUMMARY Drugs can cause prolongation of the QT interval, alone or in combination, potentially leading to fatal arrhythmias such as torsades de pointes. When prescribing drugs that prolong the QT interval, the balance of benefit versus harm should always be considered. Readouts from automated ECG machines are unreliable. The QT interval should be measured manually. Changes in heart rate influence the absolute QT interval. Heart rate correction formulae are inaccurate, particularly for fast and slow heart rates. The QT nomogram, a plot of QT interval versus heart rate, can be used as a risk assessment tool to detect an abnormal QT interval. PMID:26648606

  7. Type 2 leprosy reaction with Sweet's syndrome-like presentation*

    PubMed Central

    Chiaratti, Francielle Chiavelli; Daxbacher, Egon Luiz Rodrigues; Neumann, Antonielle Borges Faria; Jeunon, Thiago

    2016-01-01

    Leprosy is a chronic disease characterized by manifestations in the peripheral nerves and skin. The course of the disease may be interrupted by acute phenomena called reactions. This article reports a peculiar case of type 2 leprosy reaction with Sweet's syndrome-like features as the first clinical manifestation of leprosy, resulting in a delay in the diagnosis due to unusual clinical presentation. The patient had clinical and histopathological features reminiscent of Sweet's syndrome associated with clusters of vacuolated histiocytes containing acid-fast bacilli isolated or forming globi. Herein, it is discussed how to recognize type 2 leprosy reaction with Sweet's syndrome features, the differential diagnosis with type 1 leprosy reaction and the treatment options. When this kind of reaction is the first clinical presentation of leprosy, the correct diagnosis might be not suspected clinically, and established only with histopathologic evaluation. PMID:27438203

  8. Evidence for a fourth locus in Usher syndrome type I.

    PubMed Central

    Gerber, S; Larget-Piet, D; Rozet, J M; Bonneau, D; Mathieu, M; Der Kaloustian, V; Munnich, A; Kaplan, J

    1996-01-01

    Usher syndrome type I (US1) is an autosomal recessive condition in which three different genes have been already localised (USH1A, USH1B, and USH1C on chromosomes 14q32, 11q13, and 11p15 respectively). The genetic heterogeneity of US1 has been confirmed in a previous study by linkage analysis of 20 French pedigrees. Here, we report the genetic exclusion of the three previously reported loci in two large multiplex families of Moroccan and Pakistani origin, suggesting the existence of at least a fourth locus in Usher syndrome type I. PMID:8825055

  9. Mammary-type myofibroblastoma with the nephrotic syndrome

    PubMed Central

    Vankawala, Preksha; Kuperman, Michael B.; Mennel, Robert G.

    2016-01-01

    We describe a 23-year-old white man who presented with anasarca and a new periumbilical mass. He had preserved kidney function and laboratory findings consistent with nephrotic syndrome, including 9.7 g/day albuminuria. Serum serologies were positive for anti-SSa and anti-SSb and low complements but were negative for antinuclear antibody. Pathologic findings of the abdominal mass showed a mammary-type myofibroblastoma. A kidney biopsy revealed a diffuse proliferative and membranous immune-mediated glomerulonephritis with 10% interstitial fibrosis. This is a novel case of mammary-type myofibroblastoma associated with nephrotic syndrome mimicking a proliferative lupus pattern. PMID:27365885

  10. Complex regional pain syndrome after thromboendarterectomy: which type is it?

    PubMed

    Baillet, Georges; Planchon, Claude Alain; Tamgac, Feyzi; Thomassin, Martine; Foult, Jean-Marc

    2002-09-01

    The authors describe a complex regional pain syndrome (CRPS) and discuss its type according to the presence or absence of nerve injury. A patient underwent thromboendarterectomy of the right popliteal artery. Subsequently, right lower limb reflex sympathetic dystrophy developed, which was confirmed by scintigraphy and responded well to calcitonin treatment. Typing according to the new classification of CRPS type I or II with possible nerve injury is discussed, and a short review of the literature is included. PMID:12192276

  11. Use of in vitro methods to predict QT prolongation

    SciTech Connect

    Hammond, T.G. . E-mail: tim.hammond@astrazeneca.com; Pollard, C.E.

    2005-09-01

    The inhibition of the hERG-encoded potassium channel can lead to prolongation of the cardiac action potential-manifested as a prolongation of the QT interval on the ECG. Although QT interval prolongation is not dangerous per se, in a small percentage of cases, it is associated with a potentially fatal arrhythmia: Torsades de Pointes (TdP). This channel type is pharmacologically promiscuous, so many compounds have caused QT interval prolongation in man and this has led to drugs being withdrawn from the market following evidence of TdP. From a drug discovery perspective, focusing as early as possible on screening out hERG activity is important. Retrospective analysis of hERG potency versus clinical incidence of TdP suggests provisional safety margins that could be used as target values by medicinal chemists. Large safety margins will not always be possible; however, and in such circumstances, if the risk-benefit ratio still favours developing the compound, a pre-clinical assessment of the likelihood that any QT interval prolongation will or will not lead to TdP in man may be important. An isolated rabbit heart model of arrhythmia shows promise in this respect, based on a comparison of clinical data with that obtained from this assay. Specific regulatory guidance on this topic is still in the draft form but the pre-clinical document (ICH S7B) contains a largely useful perspective on how an integrated risk assessment could be formed using in vitro and in vivo assays. The role of this document is evolving however, since the draft clinical guideline (E14) suggests that irrespective of the pre-clinical data, a thorough clinical ECG study will be required at some point during development.

  12. Ehlers-danlos syndrome-hypermobility type and hemorrhoids.

    PubMed

    Plackett, Timothy P; Kwon, Edward; Gagliano, Ronald A; Oh, Robert C

    2014-01-01

    Ehlers-Danlos syndrome-hypermobility type (EDS-HT) is a connective tissue disorder associated with chronic musculoskeletal pain. The diagnosis is based on simple clinical examination, although it is easily overlooked. Herein we present a case of EDS-HT associated with hemorrhoids and suggest that there may be an association between the two conditions. PMID:24839575

  13. Free flap transfer for complex regional pain syndrome type II

    PubMed Central

    Matsuda, Ken; Kikuchi, Mamoru; Murase, Tsuyoshi; Hosokawa, Ko; Shibata, Minoru

    2014-01-01

    Abstract A patient with complex regional pain syndrome type II was successfully treated using free anterolateral thigh flap transfer with digital nerve coaptation to the cutaneous nerve of the flap. Release of the scarred tissue and soft tissue coverage with targeted sensory nerve coaptation were useful in relieving severe pain.

  14. Bilateral Horner's syndrome in cluster type headaches.

    PubMed

    Khurana, R K

    1993-09-01

    A patient with cluster type headaches demonstrated bilateral and alternating ocular sympathetic dysfunction during a spontaneous as well as a nitroglycerin-induced attack. Biochemical evaluation revealed postganglionic pupillary dysfunction on the symptomatic side and preganglionic pupillary dysfunction contralaterally. These findings defy a simple explanation regarding a central or peripheral origin of the oculocephalic sympathetic dysfunction. PMID:8262788

  15. Management of pregnancy in Crigler Najjar syndrome type 2

    PubMed Central

    Chaubal, Alisha Nitin; Patel, Ruchir; Choksi, Dhaval; Shah, Kaivan; Ingle, Meghraj; Sawant, Prabha

    2016-01-01

    Crigler Najjar syndrome is associated with indirect hyperbilirubinemia due to a deficiency of enzyme Uridine Di Phospho Glucoronosyl Transferase (UDPGT). Presented here is a case of a female in the first trimester of pregnancy, who was diagnosed to have type 2 Crigler Najjar syndrome. We also discuss the management of this rare disease especially in pregnancy. Unconjugated bilirubin can cross the placental barrier causing neurological damage in the newborn. Patient was carefully monitored during pregnancy and treatment with phenobarbitone in low doses was adjusted such that the serum bilirubin levels were below 10 mg/dL. Crigler Najjar syndrome being rare needs to be diagnosed early in pregnancy to avoid adverse fetal outcomes. Phenobarbitone being an inducer of enzyme UDPGT is used as the first line of treatment and is not teratogenic in the low doses used. Treatment protocol followed was on the basis of previous reported cases and successful perinatal outcome was achieved. PMID:27099654

  16. Adult presentation of Bartter syndrome type IV with erythrocytosis

    PubMed Central

    Heilberg, Ita Pfeferman; Tótoli, Cláudia; Calado, Joaquim Tomaz

    2015-01-01

    Abstract Bartter syndrome comprises a group of rare autosomal-recessive salt-losing disorders with distinct phenotypes, but one unifying pathophysiology consisting of severe reductions of sodium reabsorption caused by mutations in five genes expressed in the thick ascending limb of Henle, coupled with increased urinary excretion of potassium and hydrogen, which leads to hypokalemic alkalosis. Bartter syndrome type IV, caused by loss-of-function mutations in barttin, a subunit of chloride channel CLC-Kb expressed in the kidney and inner ear, usually occurs in the antenatal-neonatal period. We report an unusual case of late onset presentation of Bartter syndrome IV and mild phenotype in a 20 years-old man who had hypokalemia, deafness, secondary hyperparathyroidism and erythrocytosis. PMID:26537508

  17. A 24-HOUR AMBULATORY ECG MONITORING IN ASSESSMENT OF QT INTERVAL DURATION AND DISPERSION IN ROWERS WITH PHYSIOLOGICAL MYOCARDIAL HYPERTROPHY

    PubMed Central

    Kim, Z.F.; Bilalova, R.R.; Tsibulkin, N.A.; Almetova, R.R.; Mudarisova, R.R.; Ahmetov, I.I.

    2013-01-01

    Myocardial hypertrophy (MH) due to cardiac pathology is characterized by an increase in QT interval duration and dispersion, while the findings for exercise-induced myocardial hypertrophy are contradictory. The majority of published research findings have not explored this relationship, but there have only been a few conducted studies using 24-hour ECG monitoring. The aim of the study was to determine the QT interval duration and dispersion in short-term and 24-hour ECG in endurance athletes with myocardial hypertrophy and without it. Methods: A total of 26 well-trained rowers underwent a resting 12-lead ECG, 24-hour ECG monitoring and echocardiography. Results: Athletes with MH (n = 7) at rest did not show any increase in QTc interval duration and dispersion, or mean and maximal QTc duration in Holter monitoring compared to athletes without MH (n = 19). Left ventricular mass was not significantly correlated with any QTc characteristics. Furthermore, athletes with MH had significantly longer mean QT (P = 0.01) and maximal QT (P = 0.018) intervals in Holter monitoring and higher 24-hour heart rate variability indexes due to stronger vagal effects. Conclusions: The present study demonstrated that athlete's heart syndrome with myocardial hypertrophy as a benign phenomenon does not lead to an increase in QT interval duration, or increases in maximal and mean duration in a 24-hour ECG. An increase in QT interval duration in athletes may have an autonomic nature. PMID:24744494

  18. Genetics Home Reference: Romano-Ward syndrome

    MedlinePlus

    ... lead to fainting (syncope) or cardiac arrest and sudden death. Related Information What does it mean if a ... list from the University of Kansas Medical Center Sudden Arrhythmia Death Syndromes (SADS) Foundation: Long QT Syndrome GeneReviews (1 ...

  19. Occurrence of Parkinson's syndrome in type I Gaucher disease.

    PubMed

    Neudorfer, O; Giladi, N; Elstein, D; Abrahamov, A; Turezkite, T; Aghai, E; Reches, A; Bembi, B; Zimran, A

    1996-09-01

    Gaucher disease, the most prevalent glycolipid storage disorder, is classically subdivided into types according to the presence or absence of neurological involvement. Type I has hitherto been considered non-neuronopathic. We present six cases and a review of the literature of Parkinsonian symptoms in type I Gaucher disease patients. The hallmark of this atypical Parkinsonian syndrome is a relatively severe clinical course with early appearance of neurological signs in the 4th to 6th decade of life, aggressive progression of the signs and refractoriness to conventional anti-Parkinson therapy. We discuss the implications of these findings in the light of enzyme replacement therapy for Gaucher disease. PMID:8917744

  20. Combining QT and small-x resummations

    NASA Astrophysics Data System (ADS)

    Marzani, Simone

    2016-03-01

    We analyze transverse momentum (QT) resummation of a colorless final state, e.g. Higgs production in gluon fusion or the production of a lepton pair via the Drell-Yan mechanism, in the limit where the invariant mass of the final state is much less than the center-of-mass energy, i.e. Q2≪s . We show how the traditional resummation of logarithms of QT/Q can be supplemented with the resummation of the leading logarithmic contributions at small x =Q2/s and we compute the necessary ingredients to perform such joint resummation.

  1. Hypoglycaemia and QT interval prolongation: Detection by simultaneous Holter and continuous glucose monitoring.

    PubMed

    Lee, Angela S; Brooks, Belinda A; Simmons, Lisa; Kilborn, Michael J; Wong, Jencia; Twigg, Stephen M; Yue, Dennis K

    2016-03-01

    This study using simultaneous Holter and continuous glucose monitoring demonstrates that prolongation of QT interval can occur with hypoglycaemia in an ambulatory setting in people with type 1 and type 2 diabetes treated with insulin. This highlights the potential proarrhythmic harms associated with hypoglycaemia. PMID:26803354

  2. DRESS syndrome associated with type 2 diabetes in a child

    PubMed Central

    Erdem, Semiha Bahceci; Bag, Ozlem; Karkiner, Canan Sule Unsal; Korkmaz, Huseyin Anil; Can, Demet

    2016-01-01

    Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is an uncommon, life-threatening drug reaction. The basic findings are skin rash, multiorgan involvement, and eosinophilia. Most of the aromatic anticonvulsants, such as phenytoin, phenobarbital and carbamazepine can induce DRESS. Herein we report a 14-year-old patient with DRESS syndrome related to carbamazepine use. The patient presented with signs of involvement of the skin, lungs, liver, and microscopic hematuria. Carbamazepine treatment was discontinued; antihistamines and steroids were started. Hyperglycemia, commencing on the first dose of the steroid given, persisted even after the discontinuation of steroids and improvement of other signs. There were no signs of pancreatitis or type 1 diabetes clinically in laboratory tests. Her blood glucose levels were regulated at first with insulin and later with metformin. Within 1 year of follow-up, still regulated with oral antidiabetics, she has been diagnosed with type 2 diabetes. Formerly, long-term sequelae related to “drug rash with eosinophilia and systemic symptoms syndrome” such as hepatic and renal failure, type 1 diabetes mellitus, Grave's disease, autoimmune hemolytic anemia, and lupus have also been reported. However, up to date, no cases with type 2 diabetes have been reported as long-term sequelae. To our knowledge, this is the first case in the literature presenting with type 2 diabetes as long-term sequelae. PMID:26862317

  3. Polyglandular autoimmune syndrome type I among Iranian Jews.

    PubMed Central

    Zlotogora, J; Shapiro, M S

    1992-01-01

    Polyglandular autoimmune syndrome (PAS) has been well characterised and the accepted criteria for diagnosis are the presence of at least two of the three major components: hypoparathyroidism (HPT), candidiasis, and adrenal insufficiency (AI). HPT may, however, be the only manifestation of the syndrome. Iranian Jews, having a high rate of consanguinity, appear to be a community in which PAS type I is frequent. We report on 19 families of patients with HPT from the Iranian Jewish community assuming that they are in fact affected with PAS type I. In the 19 families, 23 patients were affected, including 11 males and 12 females. All the patients but one had HPT (96%), and most were diagnosed by the age of 20 years (91%). AI was diagnosed in five of our patients; in all cases but one it appeared after HPT. Mild oral candidiasis was present in four patients and six of the patients (three males and three females) had hypogonadism. Other features of the syndrome found in some of our patients were pernicious anaemia, hypothyroidism, and alopecia. The disease is autosomal recessive and the calculated prevalence among the Iranian Jews is 1:6500 to 1:9000. The disease is also found with a very high incidence among Finns. A comparison of the symptoms between the two groups showed clinical differences including the relative rarity of candidiasis and absence of keratopathy among the Iranian Jews. PMID:1453436

  4. Acrocephalopolysyndactyly type II--Carpenter syndrome: clinical spectrum and an attempt at unification with Goodman and Summit syndromes.

    PubMed

    Cohen, D M; Green, J G; Miller, J; Gorlin, R J; Reed, J A

    1987-10-01

    Carpenter syndrome (ACPS type II) was first described by Carpenter in 1901. The syndrome consists of acrocephaly, soft tissue syndactyly, brachy- or agenesis mesophalangy of the hands and feet, preaxial polydactyly, congenital heart disease, mental retardation, hypogenitalism, obesity, and umbilical hernia. Here we review the literature on Carpenter syndrome and add 2 affected sibs with marked intrafamilial variability. This review showed that 2 reported variations of Carpenter syndrome, Goodman and Summitt syndromes, actually fall within the clinical spectrum of this disorder. This confirms earlier suggestions of Gorlin (personal communication 1982) and Hall et al [Am J Med Genet 5:423-434, 1980]. PMID:3322002

  5. Respiratory complications of Ehlers-Danlos syndrome type IV.

    PubMed

    Hatake, Katsuhiko; Morimura, Yoshifumi; Kudo, Risa; Kawashima, Wataru; Kasuda, Shogo; Kuniyasu, Hiroki

    2013-01-01

    We describe a case of Ehlers-Danlos syndrome (EDS) type IV in a male in early half in his twenties, who experienced recurrent and eventually fatal pulmonary hemorrhage. EDS type IV is a rare disorder of type III collagen synthesis that is characterized by unusual facies, thin translucent skin with a venous vascular pattern, easy bruising, and hypermobility of the small joints. Autopsy findings showed hypermobility of the joints and distensibility of the skin. Microscopically, the abdominal skin showed substantially decreased dermal thickness. Moreover, the reticular dermis showed fine collagen bundles and large interstitial spaces compared with the skin from a normal control that showed large collagen bundles. Individual elastic fibers were also thicker than those observed in the skin of a normal control. The thoracic aorta showed thin adventitia and a relative increase in elastic fibers. The parenchyma of both the lungs showed markedly diffuse hemorrhage with hemosiderin-laden alveolar macrophages or old thrombi and organized thrombi in the small bronchi. Furthermore, both sections of the lung showed multiple fibrous nodules containing benign metaplastic bone. Vascular wall disruption and tearing of the vessel walls in the lung parenchyma were also observed. We concluded that EDS type IV led to the patient's death because of pulmonary hemorrhage. Because this syndrome resulted in the patient's death from arterial and bowel rupture, it is important to consider EDS as a potential cause of sudden death. PMID:22940417

  6. QT dynamics during treatment with sertindole

    PubMed Central

    Wang, Fan; Graff, Claus; Kanters, Jørgen K.

    2015-01-01

    Objectives: Sertindole is a nonsedating atypical antipsychotic drug with low propensity to cause extrapyramidal side effects but it has been associated with a 20 ms QTc prolongation and increased risk of cardiac events. It is uncertain whether this drug-induced increase in cardiac risk might also be revealed by dynamic measures of the QT interval such as the ratio of QT variability to heart rate variability (variability ratio [VR]). The aim of this study was to investigate the effect of sertindole on QT dynamics. Methods: QTc and the VR were assessed in an observational study using 24-hour Holter monitoring at baseline and after 3 weeks of treatment with sertindole 16 mg. The VR was calculated by dividing the standard deviation of QT intervals with the standard deviation of heart rates. Outcome measures were compared using paired t-test. Results: A total of 18 patients participated in the study, two were excluded from further analysis due to low amplitude of the T-wave. When patients were shifted to sertindole, the VR increased from 0.192 (SD 0.045) to 0.223 (SD 0.061), p = 0.02. The QTcF interval increased from 388 (SD 16) to 403 ms (SD 14), p = 0.002. There was no difference in heart rate 78 bpm (SD 8) versus 80 bpm (SD 10), p = 0.3 or heart rate variability (SDNN) 127 (SD 40) versus 115 ms (SD 45), p = 0.4. Conclusion: Sertindole was associated with 19 ms QTc prolongation and an increased ratio of QT variability to heart rate variability. Both measures may contribute to the increased cardiovascular mortality found with sertindole. PMID:25653828

  7. Jervell and Lange-Nielsen Syndrome (Long QT Syndrome).

    ERIC Educational Resources Information Center

    Hulbert, T. P.

    1994-01-01

    Clinical features, pathogenetic hypotheses, and symptoms of the cardio-auditory or surdo-cardiac disorder first reported by Jervell and Lange-Nielsen are described, and methods of diagnosis and treatment are presented, to alert teachers and other professionals to potentially life-threatening symptoms they may observe when working with deaf and…

  8. An Enhancer Polymorphism at the Cardiomyocyte Intercalated Disc Protein NOS1AP Locus Is a Major Regulator of the QT Interval

    PubMed Central

    Kapoor, Ashish; Sekar, Rajesh B.; Hansen, Nancy F.; Fox-Talbot, Karen; Morley, Michael; Pihur, Vasyl; Chatterjee, Sumantra; Brandimarto, Jeffrey; Moravec, Christine S.; Pulit, Sara L.; Pfeufer, Arne; Mullikin, Jim; Ross, Mark; Green, Eric D.; Bentley, David; Newton-Cheh, Christopher; Boerwinkle, Eric; Tomaselli, Gordon F.; Cappola, Thomas P.; Arking, Dan E.; Halushka, Marc K.; Chakravarti, Aravinda

    2014-01-01

    QT interval variation is assumed to arise from variation in repolarization as evidenced from rare Na- and K-channel mutations in Mendelian QT prolongation syndromes. However, in the general population, common noncoding variants at a chromosome 1q locus are the most common genetic regulators of QT interval variation. In this study, we use multiple human genetic, molecular genetic, and cellular assays to identify a functional variant underlying trait association: a noncoding polymorphism (rs7539120) that maps within an enhancer of NOS1AP and affects cardiac function by increasing NOS1AP transcript expression. We further localized NOS1AP to cardiomyocyte intercalated discs (IDs) and demonstrate that overexpression of NOS1AP in cardiomyocytes leads to altered cellular electrophysiology. We advance the hypothesis that NOS1AP affects cardiac electrical conductance and coupling and thereby regulates the QT interval through propagation defects. As further evidence of an important role for propagation variation affecting QT interval in humans, we show that common polymorphisms mapping near a specific set of 170 genes encoding ID proteins are significantly enriched for association with the QT interval, as compared to genome-wide markers. These results suggest that focused studies of proteins within the cardiomyocyte ID are likely to provide insights into QT prolongation and its associated disorders. PMID:24857694

  9. Griscelli syndrome type 2: A rare and fatal syndrome in a South Indian boy.

    PubMed

    Rajyalakshmi, R; Chakrapani, R N B

    2016-01-01

    Griscelli syndrome (GS) is a rare autosomal recessive disorder caused by mutation in the MYO5A (GS1), RAB27A (GS2), and MLPH (GS3) genes, characterized by a common feature, partial albinism. The common variant of three, GS type 2, in addition, shows primary immunodeficiency which leads to recurrent infections and hemophagocytic lymphohistiocytosis. We, herewith, describe a case of GS type 2, in a 4-year-old male child who presented with chronic and recurrent fever, lymphadenopathy, hepatosplenomegaly, and secondary neurological deterioration; highlighting the cytological and histopathological features of lymph nodes. Hair shaft examination of the child confirmed the diagnosis. PMID:26960655

  10. Advances in the Pathogenesis of Cardiorenal Syndrome Type 3

    PubMed Central

    Clementi, Anna; Virzì, Grazia Maria; Brocca, Alessandra; de Cal, Massimo; Pastori, Silvia; Clementi, Maurizio; Granata, Antonio; Vescovo, Giorgio; Ronco, Claudio

    2015-01-01

    Cardiorenal syndrome (CRS) type 3 is a subclassification of the CRS whereby an episode of acute kidney injury (AKI) leads to the development of acute cardiac injury or dysfunction. In general, there is limited understanding of the pathophysiologic mechanisms involved in CRS type 3. An episode of AKI may have effects that depend on the severity and duration of AKI and that both directly and indirectly predispose to an acute cardiac event. Experimental data suggest that cardiac dysfunction may be related to immune system activation, inflammatory mediators release, oxidative stress, and cellular apoptosis which are well documented in the setting of AKI. Moreover, significant derangements, such as fluid and electrolyte imbalance, metabolic acidosis, and uremia, which are typical features of acute kidney injury, may impair cardiac function. In this review, we will focus on multiple factors possibly involved in the pathogenesis issues regarding CRS type 3. PMID:25821551

  11. Ehlers-Danlos Syndrome Type IV with Bilateral Pneumothorax.

    PubMed

    Nakagawa, Hiroaki; Wada, Hiroshi; Hajiro, Takashi; Nagao, Taishi; Ogawa, Emiko; Hatamochi, Atsushi; Tanaka, Toshihiro; Nakano, Yasutaka

    2015-01-01

    A 17-year-old teen was hospitalized with bilateral pneumothorax. After the bilateral lungs were expanded using catheter tubes, he fully recovered and he was discharged from our hospital. He had a history of colon perforation. Ehlers-Danlos syndrome (EDS) was suspected due to the combination of colon perforation and pneumothorax, and EDS type IV was confirmed after a genetic study identified a c.1511g>a mutation in the COL3A1 gene. This is the first report of bilateral pneumothorax caused by EDS type IV. Clinicians should consider EDS type IV in the differential diagnosis for bilateral pneumothorax in conjunction with distinct previous histories and radiological findings. PMID:26666608

  12. Type 1 diabetes and polyglandular autoimmune syndrome: A review

    PubMed Central

    Hansen, Martin P; Matheis, Nina; Kahaly, George J

    2015-01-01

    Type 1 diabetes (T1D) is an autoimmune disorder caused by inflammatory destruction of the pancreatic tissue. The etiopathogenesis and characteristics of the pathologic process of pancreatic destruction are well described. In addition, the putative susceptibility genes for T1D as a monoglandular disease and the relation to polyglandular autoimmune syndrome (PAS) have also been well explored. The incidence of T1D has steadily increased in most parts of the world, especially in industrialized nations. T1D is frequently associated with autoimmune endocrine and non-endocrine diseases and patients with T1D are at a higher risk for developing several glandular autoimmune diseases. Familial clustering is observed, which suggests that there is a genetic predisposition. Various hypotheses pertaining to viral- and bacterial-induced pancreatic autoimmunity have been proposed, however a definitive delineation of the autoimmune pathomechanism is still lacking. In patients with PAS, pancreatic and endocrine autoantigens either colocalize on one antigen-presenting cell or are expressed on two/various target cells sharing a common amino acid, which facilitates binding to and activation of T cells. The most prevalent PAS phenotype is the adult type 3 variant or PAS type III, which encompasses T1D and autoimmune thyroid disease. This review discusses the findings of recent studies showing noticeable differences in the genetic background and clinical phenotype of T1D either as an isolated autoimmune endocrinopathy or within the scope of polyglandular autoimmune syndrome. PMID:25685279

  13. Clinical findings in obligate carriers of type I Usher syndrome

    SciTech Connect

    Wagenaar, M.; Rahe, B. ter; Aarem, A. van; Huygen, P.; Admiraal, R.

    1995-11-20

    Seventeen obligate carriers from nine families with autosomal recessive Usher syndrome type I underwent otological, audiological, vestibular, and ophthalmological examination in order to identify possible manifestations of heterozygosity. Linkage studies were performed and six families showed linkage to chromosome region 11q13.5 while 3 families have so far failed to show linkage to the candidate regions. Eight obligate carriers had an abnormal puretone audiogram. Two different audiometric patterns could be distinguished when hearing loss was corrected for age and sex. Four carriers (24%) had significant sensorineural hearing loss (SNHL) which increased at higher frequencies. The other 13 carriers had SNHL of about 10 dB at 0.25 and 0.5 kHz, but less at higher frequencies. Vestibular findings were generally normal. Electrooculography demonstrated a significant lower mean light peak/dark trough ratio in Usher type I carriers compared to normal control individuals. The methods used in this study were found not to be specific enough to clinically identify carriers of Usher type I syndrome. Nevertheless it is remarkable that a number of obligate carriers showed significant audiological and ophthalmological abnormalities. 29 refs., 1 fig., 3 tabs.

  14. Paradoxical hypertension and salt wasting in Type II Bartter syndrome.

    PubMed

    Chan, Winnie Kwai-Yu; To, Ka Fai; Tong, Joanna H M; Law, Chi Wai

    2012-06-01

    Ante/neonatal Bartter syndrome (BS) is a rare hereditary disorder. It is characterized by renal salt wasting, hypokalaemic metabolic alkalosis, high renin and aldosterone but normal blood pressure. We report a low birth weight newborn baby who presented with repeated apnoea shortly after birth as well as hyponatraemia, hypochloraemia, hyperkalaemia and metabolic acidosis. Her biochemical features mimicked pseudohypoaldosteronism but with initial hypertension, which had not been described in BS. Her subsequent genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II BS. PMID:26069767

  15. Skeletal abnormalities of tricho-rhino-phalangeal syndrome type I.

    PubMed

    de Barros, Guilherme Monteiro; Kakehasi, Adriana Maria

    2016-01-01

    The tricho-rhino-phalangeal syndrome (TRPS) type I is a rare genetic disorder related to the TRPS1 gene mutation in chromosome 8, characterized by craniofacial abnormalities and disturbances in formation and maturation of bone matrix. The hallmarks are sparse and brittle hair, tendency to premature baldness, bulbous nose called pear-shaped, long and flat filter and low ear implantation. The most noticeable skeletal changes are clinodactyly, phalangeal epiphyses of the hands appearing as cone-shaped, short stature and hip joint malformations. We report a case of a teenager boy diagnosed with TRPS and referred for rheumatologic evaluation due to joint complaints. PMID:27267340

  16. Drug-induced Inhibition and Trafficking Disruption of ion Channels: Pathogenesis of QT Abnormalities and Drug-induced Fatal Arrhythmias.

    PubMed

    Cubeddu, Luigi X

    2016-01-01

    Risk of severe and fatal ventricular arrhythmias, presenting as Torsade de Pointes (TdP), is increased in congenital and acquired forms of long QT syndromes (LQTS). Drug-induced inhibition of K+ currents, IKs, IKr, IK1, and/or Ito, delay repolarization, prolong QT, and increase the risk of TdP. Drug-induced interference with IKr is the most common cause of acquired LQTS/TdP. Multiple drugs bind to KNCH2-hERG-K+ channels affecting IKr, including antiarrythmics, antibiotics, antivirals, azole-antifungals, antimalarials, anticancer, antiemetics, prokinetics, antipsychotics, and antidepressants. Azithromycin has been recently added to this list. In addition to direct channel inhibition, some drugs interfere with the traffic of channels from the endoplasmic reticulum to the cell membrane, decreasing mature channel membrane density; e.g., pentamidine, geldalamicin, arsenic trioxide, digoxin, and probucol. Other drugs, such as ketoconazole, fluoxetine, norfluoxetine, citalopram, escitalopram, donepezil, tamoxifen, endoxifen, atazanavir, and roxitromycin, induce both direct channel inhibition and impaired channel trafficking. Although many drugs prolong the QT interval, TdP is a rare event. The following conditions increase the risk of drug-induced TdP: a) Disease states/electrolyte levels (heart failure, structural cardiac disease, bradycardia, hypokalemia); b) Pharmacogenomic variables (presence of congenital LQTS, subclinical ion-channel mutations, history of or having a relative with history of drug-induced long QT/TdP); c) Pharmacodynamic and kinetic factors (high doses, women, elderly, metabolism inhibitors, combining two or more QT prolonging drugs, drugs that prolong the QT and increase QT dispersion, and drugs with multiple actions on ion channels). Because most of these conditions are preventable, careful evaluation of risk factors and increased knowledge of drug use associated with repolarization abnormalities are strongly recommended. PMID:26926294

  17. Difficulty eating and significant weight loss in joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type.

    PubMed

    Baeza-Velasco, Carolina; Van den Bossche, Thomas; Grossin, Daniel; Hamonet, Claude

    2016-06-01

    Joint Hypermobility Syndrome, also known as Ehlers-Danlos Syndrome Hypermobility Type (JHS/EDS-HT), is a heritable disorder of connective tissue, common but poorly known by the medical community. Although generalized joint hypermobility and fragility of tissues have been described as core features, recent research highlights the multisystemic nature of JHS/EDS-HT, which presents with a wide range of articular and extra-articular symptoms. Among these, gastrointestinal problems, temporomandibular disorders, and smell and taste abnormalities are common among those affected, having significant implications for eating. The present work reviews the literature linking JHS/EDS-HT and eating problems. Two illustrative case reports, in which JHS/EDS-HT manifestations contribute to developing and maintaining disturbed eating behaviors and significant weight loss, are presented. PMID:26506923

  18. A neurodystrophic syndrome resembling carbohydrate-deficient glycoprotein syndrome type III.

    PubMed

    Stibler, H; Gylje, H; Uller, A

    1999-04-01

    A 10-month old girl is described with a serum transferrin isoform abnormality of the same kind as in two previously reported girls with carbohydrate-deficient glycoprotein syndrome type III. This patient presented with joint abnormalities and rapidly developing hypsarrhythmia, hypotonia, psychomotor delay and growth retardation. Fingers, toes, nails and local skin were dysmorphic. She had pale optic discs, thoracic syringomyelia and frontal lobe atrophy at three months. The CDT value in serum was greatly elevated. Several carbohydrate-deficient isoforms were found in transferrin (four), alpha1-antitrypsin (three), antithrombin (two) and thyroxine-binding globulin (four). Mutations in the CDGS 1-gene were excluded. The CDGS III glycoprotein abnormality most probably represents a distinct disorder of glycoprotein metabolism, and needs to be considered in unclear hypsarrhythmia with developmental delay. Dysmorphic features may be added to this syndrome. PMID:10401691

  19. Ehlers-Danlos Syndrome Type IV: A Case Report.

    PubMed

    Soo-Hoo, Sarah; Porten, Brandon R; Engstrom, Bjorn I; Skeik, Nedaa

    2016-04-01

    Ehlers-Danlos syndrome (EDS) encompasses a group of rare genetic connective tissue disorders. The vascular type (type IV) poses the most serious risk to patients. Diagnosis is usually difficult, especially if patients lack a family history. Life-threatening vascular emergency such as dissection or rupture can be the first presenting symptom. Management of the disease can pose a clinical challenge due to the emergency of presentation, tissue friability, and lack of clear management recommendations. We report a unique case of a 40-year-old man who presented with a ruptured celiac artery and a strong family history of EDS. This case highlights the difficulties and complications associated with treating this uncommon and serious disease. PMID:26975607

  20. Anisometropic amblyopia in a case of type 2 Waardenburg syndrome.

    PubMed

    Akal, Ali; Göncü, Tugba; Boyaci, Nurefsan; Yılmaz, Ömer Faruk

    2013-01-01

    This study presents a case of an 8-year-old boy with iris heterochromia and anisometropic amblyopia who was diagnosed with Waardenburg syndrome (WS) type 2. An ophthalmic examination revealed iris heterochromia and anisometropic amblyopia in our patient. In the systemic examination, a white forelock and vitiligo on the arms and body were observed and neurosensory hearing loss was revealed, for which the patient used hearing aids. Identification and typing of patients with WS is crucial to address neurosensory hearing loss, glaucoma and fundus changes. While it might be challenging to communicate with a patient with speech and hearing problems, visual acuity should be examined carefully and probable amblyopia should be identified. Anterior segment changes and signs of glaucoma should also be evaluated in detail. PMID:24351514

  1. Generalized joint hypermobility, joint hypermobility syndrome and Ehlers-Danlos syndrome, hypermobility type.

    PubMed

    Castori, Marco; Colombi, Marina

    2015-03-01

    This issue of the American Journal of Medical Genetics Seminar Series Part C is dedicated to generalized joint hypermobility (gJHM), joint hypermobility syndrome (JHS), and Ehlers-Danlos syndrome, hypermobility type (EDS-HT). gJHM is the best known clinical manifestation of inherited defects of the connective tissue. On the other side, JHS and EDS-HT are actually considered one and the same from a clinical perspective by most practitioners and researchers (i.e., JHS/EDS-HT), and their molecular basis remains unknown. For decades, "non-syndromic" gJHM and JHS/EDS-HT have been thought to be simple clinical curiosities or an asset for the "affected" individual. In recent years, the attention on these partially overlapping phenotypes has increased, as they are now recognized risk factors for a series of non-communicable diseases and long-term disabilities. This series consists of 10 papers focused on three main topics, namely (i) assessment and differential diagnosis of children and adults with gJHM, (ii) systematic presentation of selected key non-articular manifestations of JHS/EDS-HT and actual perception of physiotherapy as the best therapeutic resource for this condition, and (iii) exploration of the available knowledge relating "congenital laxity of tissues" to various dysfunctions of the nervous system during development and adulthood. The contributors hope that this collection raises attention to this fascinating field of knowledge, which seems to have ramifications in virtually all medical disciplines. PMID:25821089

  2. Relationship between fatigue and gait abnormality in joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type.

    PubMed

    Celletti, Claudia; Galli, Manuela; Cimolin, Veronica; Castori, Marco; Albertini, Giorgio; Camerota, Filippo

    2012-01-01

    Ehlers-Danlos syndrome (EDS) is a clinically and genetically heterogeneous group of inherited connective tissue disorders characterised by joint hypermobility, skin hyperextensibility and tissue fragility. It has recently been shown that muscle weakness occurs frequently in EDS, and that fatigue is a common and clinically important symptom. The aim of this study was to investigate the relationship between fatigue severity and the gait pattern using 3D Gait Analysis (GA). Eleven individuals with Joint Hypermobility Syndrome/Ehlers-Danlos Syndrome Hypermobility type (JHS/EDS-HT) were investigated using muscle strength measured with standardised questionnaire measuring fatigue (Fatigue Severity Scale, FSS) and quantitative 3D GA. Our data showed that FSS value well correlated with the peak of vertical component of ground reaction force (r=-0.66, p<0.05). The negative correlation gives evidence that the higher the fatigue is the more reduced force is during gait. Our results showed that the ground reaction force has been applied as a functional evaluation score for detecting pathology in gait of JHS/EDS-HT participants and the found correlation between vertical force and fatigue demonstrated that muscle fatigue may be associated with a loss of proprioceptive acuity in lower limb muscles. PMID:22819599

  3. Genetics Home Reference: Jervell and Lange-Nielsen syndrome

    MedlinePlus

    ... heartbeats increase the risk of fainting (syncope) and sudden death. Related Information What does it mean if a ... list from the University of Kansas Medical Center Sudden Arrhythmia Death Syndromes (SADS) Foundation: Long QT Syndrome GeneReviews (1 ...

  4. Mutations in PIEZO2 Cause Gordon Syndrome, Marden-Walker Syndrome, and Distal Arthrogryposis Type 5

    PubMed Central

    McMillin, Margaret J.; Beck, Anita E.; Chong, Jessica X.; Shively, Kathryn M.; Buckingham, Kati J.; Gildersleeve, Heidi I.S.; Aracena, Mariana I.; Aylsworth, Arthur S.; Bitoun, Pierre; Carey, John C.; Clericuzio, Carol L.; Crow, Yanick J.; Curry, Cynthia J.; Devriendt, Koenraad; Everman, David B.; Fryer, Alan; Gibson, Kate; Giovannucci Uzielli, Maria Luisa; Graham, John M.; Hall, Judith G.; Hecht, Jacqueline T.; Heidenreich, Randall A.; Hurst, Jane A.; Irani, Sarosh; Krapels, Ingrid P.C.; Leroy, Jules G.; Mowat, David; Plant, Gordon T.; Robertson, Stephen P.; Schorry, Elizabeth K.; Scott, Richard H.; Seaver, Laurie H.; Sherr, Elliott; Splitt, Miranda; Stewart, Helen; Stumpel, Constance; Temel, Sehime G.; Weaver, David D.; Whiteford, Margo; Williams, Marc S.; Tabor, Holly K.; Smith, Joshua D.; Shendure, Jay; Nickerson, Deborah A.; Bamshad, Michael J.

    2014-01-01

    Gordon syndrome (GS), or distal arthrogryposis type 3, is a rare, autosomal-dominant disorder characterized by cleft palate and congenital contractures of the hands and feet. Exome sequencing of five GS-affected families identified mutations in piezo-type mechanosensitive ion channel component 2 (PIEZO2) in each family. Sanger sequencing revealed PIEZO2 mutations in five of seven additional families studied (for a total of 10/12 [83%] individuals), and nine families had an identical c.8057G>A (p.Arg2686His) mutation. The phenotype of GS overlaps with distal arthrogryposis type 5 (DA5) and Marden-Walker syndrome (MWS). Using molecular inversion probes for targeted sequencing to screen PIEZO2, we found mutations in 24/29 (82%) DA5-affected families and one of two MWS-affected families. The presence of cleft palate was significantly associated with c.8057G>A (Fisher’s exact test, adjusted p value < 0.0001). Collectively, although GS, DA5, and MWS have traditionally been considered separate disorders, our findings indicate that they are etiologically related and perhaps represent variable expressivity of the same condition. PMID:24726473

  5. Chronic pain in hypermobility syndrome and Ehlers–Danlos syndrome (hypermobility type): it is a challenge

    PubMed Central

    Scheper, Mark C; de Vries, Janneke E; Verbunt, Jeanine; Engelbert, Raoul HH

    2015-01-01

    Generalized joint hypermobility (GJH) is highly prevalent among patients diagnosed with chronic pain. When GJH is accompanied by pain in ≥4 joints over a period ≥3 months in the absence of other conditions that cause chronic pain, the hypermobility syndrome (HMS) may be diagnosed. In addition, GJH is also a clinical sign that is frequently present in hereditary diseases of the connective tissue, such as the Marfan syndrome, osteogenesis imperfecta, and the Ehlers–Danlos syndrome. However, within the Ehlers–Danlos spectrum, a similar subcategory of patients having similar clinical features as HMS but lacking a specific genetic profile was identified: Ehlers–Danlos syndrome hypermobility type (EDS-HT). Researchers and clinicians have struggled for decades with the highly diverse clinical presentation within the HMS and EDS-HT phenotypes (Challenge 1) and the lack of understanding of the pathological mechanisms that underlie the development of pain and its persistence (Challenge 2). In addition, within the HMS/EDS-HT phenotype, there is a high prevalence of psychosocial factors, which again presents a difficult issue that needs to be addressed (Challenge 3). Despite recent scientific advances, many obstacles for clinical care and research still remain. To gain further insight into the phenotype of HMS/EDS-HT and its mechanisms, clearer descriptions of these populations should be made available. Future research and clinical care should revise and create consensus on the diagnostic criteria for HMS/EDS-HT (Solution 1), account for clinical heterogeneity by the classification of subtypes within the HMS/EDS-HT spectrum (Solution 2), and create a clinical core set (Solution 3). PMID:26316810

  6. Chronic pain in hypermobility syndrome and Ehlers-Danlos syndrome (hypermobility type): it is a challenge.

    PubMed

    Scheper, Mark C; de Vries, Janneke E; Verbunt, Jeanine; Engelbert, Raoul Hh

    2015-01-01

    Generalized joint hypermobility (GJH) is highly prevalent among patients diagnosed with chronic pain. When GJH is accompanied by pain in ≥4 joints over a period ≥3 months in the absence of other conditions that cause chronic pain, the hypermobility syndrome (HMS) may be diagnosed. In addition, GJH is also a clinical sign that is frequently present in hereditary diseases of the connective tissue, such as the Marfan syndrome, osteogenesis imperfecta, and the Ehlers-Danlos syndrome. However, within the Ehlers-Danlos spectrum, a similar subcategory of patients having similar clinical features as HMS but lacking a specific genetic profile was identified: Ehlers-Danlos syndrome hypermobility type (EDS-HT). Researchers and clinicians have struggled for decades with the highly diverse clinical presentation within the HMS and EDS-HT phenotypes (Challenge 1) and the lack of understanding of the pathological mechanisms that underlie the development of pain and its persistence (Challenge 2). In addition, within the HMS/EDS-HT phenotype, there is a high prevalence of psychosocial factors, which again presents a difficult issue that needs to be addressed (Challenge 3). Despite recent scientific advances, many obstacles for clinical care and research still remain. To gain further insight into the phenotype of HMS/EDS-HT and its mechanisms, clearer descriptions of these populations should be made available. Future research and clinical care should revise and create consensus on the diagnostic criteria for HMS/EDS-HT (Solution 1), account for clinical heterogeneity by the classification of subtypes within the HMS/EDS-HT spectrum (Solution 2), and create a clinical core set (Solution 3). PMID:26316810

  7. Drug-induced QT interval prolongation: mechanisms and clinical management

    PubMed Central

    Nachimuthu, Senthil; Assar, Manish D.

    2012-01-01

    The prolonged QT interval is both widely seen and associated with the potentially deadly rhythm, Torsades de Pointes (TdP). While it can occur spontaneously in the congenital form, there is a wide array of drugs that have been implicated in the prolongation of the QT interval. Some of these drugs have either been restricted or withdrawn from the market due to the increased incidence of fatal polymorphic ventricular tachycardia. The list of drugs that cause QT prolongation continues to grow, and an updated list of specific drugs that prolong the QT interval can be found at www.qtdrugs.org. This review focuses on the mechanism of drug-induced QT prolongation, risk factors for TdP, culprit drugs, prevention and monitoring of prolonged drug-induced QT prolongation and treatment strategies. PMID:25083239

  8. Drug-induced QT interval prolongation: does ethnicity of the thorough QT study population matter?

    PubMed Central

    Shah, Rashmi R

    2013-01-01

    Inter-ethnic differences in drug responses have been well documented. Drug-induced QT interval prolongation is a major safety concern and therefore, regulatory authorities recommend a clinical thorough QT study (TQT) to investigate new drugs for their QT-prolonging potential. A positive study, determined by breach of a preset regulatory threshold, significantly influences late phase clinical trials by requiring intense ECG monitoring. A few studies that are currently available, although not statistically conclusive at present, question the assumption that ethnicity of the study population may not influence the outcome of a TQT study. Collective consideration of available pharmacogenetic and clinical information suggests that there may be inter-ethnic differences in QT-prolonging effects of drugs and that Caucasians may be more sensitive than other populations. The information also suggest s that (a) these differences may depend on the QT-prolonging potency of the drug and (b) exposure–response (E–R) analysis may be more sensitive than simple changes in QTc interval in unmasking this difference. If the QT response in Caucasians is generally found to be more intense than in non-Caucasians, there may be significant regulatory implications for domestic acceptance of data from a TQT study conducted in foreign populations. However, each drug will warrant an individual consideration when extrapolating the results of a TQT studyfrom one ethnic population to another and the ultimate clinical relevance of any difference. Further adequately designed and powered studies, investigating the pharmacologic properties and E–R relationships of additional drugs with different potencies, are needed in Caucasians, Oriental/Asian and African populations before firm conclusions can be drawn. PMID:22882246

  9. Targeted Exon Sequencing in Usher Syndrome Type I

    PubMed Central

    Bujakowska, Kinga M.; Consugar, Mark; Place, Emily; Harper, Shyana; Lena, Jaclyn; Taub, Daniel G.; White, Joseph; Navarro-Gomez, Daniel; Weigel DiFranco, Carol; Farkas, Michael H.; Gai, Xiaowu; Berson, Eliot L.; Pierce, Eric A.

    2014-01-01

    Purpose. Patients with Usher syndrome type I (USH1) have retinitis pigmentosa, profound congenital hearing loss, and vestibular ataxia. This syndrome is currently thought to be associated with at least six genes, which are encoded by over 180 exons. Here, we present the use of state-of-the-art techniques in the molecular diagnosis of a cohort of 47 USH1 probands. Methods. The cohort was studied with selective exon capture and next-generation sequencing of currently known inherited retinal degeneration genes, comparative genomic hybridization, and Sanger sequencing of new USH1 exons identified by human retinal transcriptome analysis. Results. With this approach, we were able to genetically solve 14 of the 47 probands by confirming the biallelic inheritance of mutations. We detected two likely pathogenic variants in an additional 19 patients, for whom family members were not available for cosegregation analysis to confirm biallelic inheritance. Ten patients, in addition to primary disease–causing mutations, carried rare likely pathogenic USH1 alleles or variants in other genes associated with deaf-blindness, which may influence disease phenotype. Twenty-one of the identified mutations were novel among the 33 definite or likely solved patients. Here, we also present a clinical description of the studied cohort at their initial visits. Conclusions. We found a remarkable genetic heterogeneity in the studied USH1 cohort with multiplicity of mutations, of which many were novel. No obvious influence of genotype on phenotype was found, possibly due to small sample sizes of the genotypes under study. PMID:25468891

  10. Acute Type A Aortic Dissection Missed as Acute Coronary Syndrome

    PubMed Central

    Ansari-Ramandi, Mohammad Mostafa; Firoozi, Ata

    2016-01-01

    Although the aortic dissection is not common, its outcome is frequently fatal, and many patients with aortic dissection die before referral to the hospital or any diagnostic testing. The symptoms of aortic dissection can be similar to myocardial ischemia. A 66-year-old male was referred to our hospital with suspicion of aortic dissection after echocardiography done for evaluating his high blood pressure. He had symptoms of acute coronary syndrome two years before and had done coronary angiography. On presentation to our hospital he had a high blood pressure. On reviewing his past medical history and examining, in the film of coronary angiography, the dissection flap in ascending aorta was identified. Although type A aortic dissection is a catastrophic condition with high mortality and requires prompt surgical treatment but in some cases it may be misdiagnosed as acute coronary syndrome. Sometimes against its high mortality when left untreated, patients survive and are diagnosed later in life incidentally. So it is of great importance to have great clinical suspicion for aortic dissection in patients referring to the hospital with chest pain and the predisposing factors. PMID:27437290

  11. [Otoneurologic symptoms associated with Arnold-Chiari syndrome type I].

    PubMed

    Urban, Irena; Namysłowski, Grzegorz; Morawski, Krzysztof; Wojtacha, Maciej

    2004-01-01

    This study presents two cases of Arnold-Chiari malformation type I. In a 26-year old man, right side deafness and left side sensorineural hearing loss at high frequencies occurred. Another patient, a 48-year old man also complained of sensorineural hearing loss and dizziness, that appeared a year and half ago. In addition, this patient had episodes of vertigo with nausea and vomit that occurred about one year before main symptoms. In both patients ENT examinations were performed as well as an audiological diagnostic battery including tonal- and impedance-audiometry, auditory brainstem responses, distortion product otoacoustic emissions and electroencephalography. Magnetic resonance imaging (MRI) showed pathological changes in the cerebello-pontine angle region that allowed diagnosing Arnold-Chiari malformation in both cases. Additionally, angio-MRI performed in patient with right side deafness revealed cochleovestibular nerve compression syndrome on the same side. Presumably, both anomalies occurring simultaneously in this patient might be responsible for deafness in the right ear, instead of mild or moderate hearing loss and tinnitus usually expected according to the literature. The paper presented two cases of Arnold-Chiari malformation with co-existing cochleovestibular nerve compression syndrome in one case. The importance of both audiological diagnostic battery and MRI in diagnostic procedures of this malformation has been demonstrated. PMID:15307473

  12. Hermansky-Pudlak syndrome type 4 with interstitial pneumonia.

    PubMed

    Sakata, Yoshihiko; Kawamura, Kodai; Ichikado, Kazuya; Suga, Moritaka; Yoshioka, Masakazu

    2013-01-01

    Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism, bleeding tendency, and lysosomal accumulation of ceroid-like material, with occasional development of interstitial pneumonia (IP). Nine genetically distinct subtypes of HPS are known in humans; IP develops primarily in types 1 and 4. Most reported cases of HPS with IP are type 1, and there are no published reports of type 4 in Japanese individuals. A 58-year-old man with congenital oculocutaneous albinism and progressive dyspnea for 1 month was admitted to our hospital. We administered high-dose corticosteroids on the basis of a diagnosis of acute exacerbation of interstitial pneumonia. Respiratory symptoms and the findings of high-resolution computed tomography (CT) showed improvement. He was diagnosed with HPS type 4 with interstitial pneumonia on the basis of gene analysis. He has been receiving pirfenidone for 1 year and his condition is stable. This is the first report on the use of pirfenidone for HPS with IP caused by a novel mutation in the HPS4 gene. We conclude that HPS should be suspected in patients with albinism and interstitial pneumonia. High-dose corticosteroid treatment may be useful in cases of acute exacerbation of interstitial pneumonia due to HPS-4, and pirfenidone may be useful and well tolerated in patients with HPS-4. PMID:26029628

  13. Creation of a knowledge management system for QT analyses.

    PubMed

    Tornøe, Christoffer W; Garnett, Christine E; Wang, Yaning; Florian, Jeffry; Li, Michael; Gobburu, Jogarao V

    2011-07-01

    An increasing number of thorough QT (TQT) reports are being submitted to the US Food and Drug Administration's interdisciplinary review team for QT (IRT-QT), requiring time-intensive quantitative analyses by a multidisciplinary review team within 45 days. This calls for systematic learning to guide future trials and policies by standardizing and automating the QT analyses to improve review efficiency, provide consistent advice, and enable pooled data analyses to answer key regulatory questions. The QT interval represents the time from initiation of ventricular depolarization to completion of ventricular repolarization recorded by electrocardiograph (ECG) and is used in the proarrhythmic risk assessment. The developed QT knowledge management system is implemented in the R package "QT." Data from 11 crossover TQT studies including time-matched ECGs and pharmacokinetic measurements following single doses of 400 to 1200 mg moxifloxacin were used for the QT analysis example. The automated workflow was divided into 3 components (data management, analysis, and archival). The generated data sets, scripts, tables, and graphs are automatically stored in a queryable repository and summarized in an analysis report. More than 100 TQT studies have been analyzed using the system since 2007. This has dramatically reduced the time needed to review TQT studies and has made the IRT-QT reviews consistent across reviewers. Furthermore, the system enables leveraging prior knowledge through pooled data analyses to answer policy-related questions and to understand the various effects that influence study results. PMID:20978278

  14. Acquired hemophilia complicated by cardiorenal syndrome type 3

    PubMed Central

    Sharma, Rakesh; Dash, Sananta Kumar; Chawla, Rajesh; Kansal, Sudha; Agrawal, Devender Kumar; Dua, Harsh

    2013-01-01

    Development of autoantibodies against coagulation factor VIII (FVIII) leads to a rare condition defined as acquired hemophilia (AH). If not diagnosed and treated early, AH may be associated with high mortality and morbidity. A 65-year-old woman presented with history of macrohematuria, acute renal failure, cardiogenic shock, and acute respiratory failure. Blood investigation revealed azotemia, prolonged activated partial thromboplastin time (aPTT), coagulation FVIII level of <1%, and presence of FVIII inhibitor. Echocardiography showed global hypokinesia and ultrasonography and computed tomography (CT) revealed bilateral hydroureteronephrosis. The final diagnosis was acquired hemophilia A, complicated by acute obstructive renal failure and cardiorenal syndrome (CRS) type 3. Patient was managed with mechanical ventilation, heparin-free hemodialysis, negative fluid balance, recombinant activated factor VII, and prednisolone. Hematuria was relieved, renal function improved, and cardiac function showed improvement on repeat echocardiography. Patient was discharged on prednisolone with subsequent follow ups. PMID:24501492

  15. Ehlers-Danlos Syndrome Type VIIC: A Mexican Case Report.

    PubMed

    Rincón-Sánchez, Ana Rosa; Arce, Irma Elia; Tostado-Rabago, Enrique Alejandro; Vargas, Alberto; Padilla-Gómez, Luis Alfredo; Bolaños, Alejandro; Barrios-Guyot, Selenne; Anguiano-Alvarez, Víctor Manuel; Ledezma-Rodríguez, Víctor Chistian; Islas-Carbajal, María Cristina; Rivas-Estilla, Ana María; Feria-Velasco, Alfredo; Dávalos, Nory Omayra

    2012-01-01

    Ehlers-Danlos syndrome (EDS) is a heterogeneous group of heritable connective tissue disorders whose primary clinical features include soft and extensible skin, articular hypermobility and tissue fragility. EDS type VIIC or 'human dermatosparaxis' is an autosomal recessive disease characterized by severe skin fragility and sagging redundant skin (major criteria) with a soft, doughy texture, easy bruising, premature rupture of fetal membranes and large hernias (minor criteria). Dermatosparaxis (meaning 'tearing of skin'), which has been described in several non-human species, is a disorder of the connective tissue resulting from a deficiency of the enzyme that cleaves the registration peptide off the N-terminal end of collagen after it has been secreted from fibroblasts. We describe a Mexican case from consanguineous parents with all the phenotypical characteristics previously described, plus skeletal abnormalities. PMID:22787447

  16. Hypnosis for postpolio syndrome & Type-A behavior.

    PubMed

    Hammond, D C

    1991-07-01

    Many of the hundreds of thousands of survivors of polio are now developing postpolio syndrome. Symptoms include progressive muscle weakness, fatigue, decreased endurance, joint and muscle pain, weight gain, respiratory difficulties, and sleep disturbance, often precipitated or exacerbated by a Type-A Personality pattern. A postpolio patient with Type-A Personality was taught self-hypnosis as a vital component of treatment. Pre-post testing included the Profile of Mood States, the State-Trait Anxiety Inventory, the State-Trait Anger Inventory, and the Personal Orientation Inventory; the patient's spouse was interviewed during the follow-up. At the 6-month follow-up, improvements were documented in pain level, depression, self-regard, self-acceptance, capacity for intimate contact, time competence (living in the present), confusion, anxiety, insomnia, and in trait and state anger. Only a mild improvement occurred in fatigue, and no improvement was found in weight control. Follow-up at 12 months confirmed the maintenance of improvements. Self-hypnosis training may prove extremely helpful for postpolio patients and may prove helpful in modifying central characteristics of Type-A Personality. PMID:1951142

  17. Gastrointestinal and nutritional issues in joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type.

    PubMed

    Castori, Marco; Morlino, Silvia; Pascolini, Giulia; Blundo, Carlo; Grammatico, Paola

    2015-03-01

    Gastrointestinal involvement is a well known complication of Ehlers-Danlos syndromes (EDSs), mainly in form of abdominal emergencies due to intestinal/abdominal vessels rupture in vascular EDS. In the last decade, a growing number of works investigated the relationship between a wide spectrum of chronic gastrointestinal complaints and various EDS forms, among which the hypermobility type (a.k.a. joint hypermobility syndrome; JHS/EDS-HT) was the most studied. The emerging findings depict a major role for gastrointestinal involvement in the health status and, consequently, management of JHS/EDS-HT patients. Nevertheless, fragmentation of knowledge limits its impact on practice within the boundaries of highly specialized clinics. In this paper, literature review on gastrointestinal manifestations in JHS/EDS-HT was carried out and identified papers categorized as (i) case-control/cohort studies associating (apparently non-syndromic) joint hypermobility and gastrointestinal involvement, (ii) case-control/cohort studies associating JHS/EDS-HT and gastrointestinal involvement, (iii) case reports/series on various gastrointestinal complications in (presumed) JHS/EDS-HT, and (iv) studies reporting gastrointestinal features in heterogeneous EDS patients' cohorts. Gastrointestinal manifestations of JHS/EDS-HT were organized and discussed in two categories, including structural anomalies (i.e., abdominal/diaphragmatic hernias, internal organ/pelvic prolapses, intestinal intussusceptions) and functional features (i.e., dysphagia, gastro-esophageal reflux, dyspepsia, recurrent abdominal pain, constipation/diarrhea), with emphasis on practice and future implications. In the second part of this paper, a summary of possible nutritional interventions in JHS/EDS-HT was presented. Supplementation strategies were borrowed from data available for general population with minor modifications in the light of recent discoveries in the pathogenesis of selected JHS/EDS-HT features. PMID

  18. Neurodevelopmental attributes of joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type: Update and perspectives.

    PubMed

    Ghibellini, Giulia; Brancati, Francesco; Castori, Marco

    2015-03-01

    In the last decade, increasing attention has been devoted to the extra-articular and extra-cutaneous manifestations of joint hypermobility syndrome, also termed Ehlers-Danlos syndrome, hypermobility type (i.e., JHS/EDS-HT). Despite the fact that the current diagnostic criteria for both disorders remain focused on joint hypermobility, musculoskeletal pain and skin changes, medical practice and research have started investigating a wide spectrum of visceral, neurological and developmental complications, which represent major burdens for affected individuals. In particular, children with generalized joint hypermobility often present with various neurodevelopmental issues and can be referred for neurological consultation. It is common that investigations in these patients yield negative or inconsistent results, eventually leading to the exclusion of any structural neurological or muscle disorder. In the context of specialized clinics for connective tissue disorders, a clear relationship between generalized joint hypermobility and a characteristic neurodevelopmental profile affecting coordination is emerging. The clinical features of these patients tend to overlap with those of developmental coordination disorder and can be associated with learning and other disabilities. Physical and psychological consequences of these additional difficulties add to the chief manifestations of the pre-existing connective tissue disorder, affecting the well-being and development of children and their families. In this review, particular attention is devoted to the nature of the link between joint hypermobility, coordination difficulties and neurodevelopmental issues in children. Presumed pathogenesis and management issues are explored in order to attract more attention on this association and nurture future clinical research. PMID:25654988

  19. Gait strategy in patients with Ehlers-Danlos syndrome hypermobility type and Down syndrome.

    PubMed

    Rigoldi, Chiara; Galli, Manuela; Cimolin, Veronica; Camerota, Filippo; Celletti, Claudia; Tenore, Nunzio; Albertini, Giorgio

    2012-01-01

    People suffering from Ehlers-Danlos syndrome (EDS) hypermobility type present a severe ligament laxity that results in difficulties in muscle force transmission. The same condition is present in people suffering from Down syndrome (DS) even if their clumsy movements are due to cerebral and cognitive impairments. The aim of this study was to quantify the gait patterns of subjects with EDS and with DS using Gait Analysis (GA). We quantified the gait strategy in 12 EDS individuals and in 16 participants with DS. Both pathological groups were compared to 20 age-matched healthy controls in terms of kinematics and kinetics. Results showed that DS individuals are characterized by a more compromised gait pattern than EDS participants, even if both groups are characterized by joint hypermobility. All the patients showed significant decreased of ankle stiffness probably due to congenital hypotonia and ligament laxity, while different values of hip stiffness. These findings help to elucidate the complex biomechanical changes due to joint hypermobility and may have a major role in the multidimensional evaluation and tailored management of these patients. PMID:22522202

  20. Joint hypermobility syndrome (a.k.a. Ehlers-Danlos Syndrome, Hypermobility Type): an updated critique.

    PubMed

    Castori, M

    2013-02-01

    Joint hypermobility syndrome, alternatively termed Ehlers-Danlos syndrome hypermobility type (JHS/EDS-HT), is likely the most common, though the least recognized heritable connective tissue disorder. While its leading clinical features typically affect joints, recent evidence indicates a wider spectrum of satellite symptoms/dysfunctions, involving practically all major systems and organs. Accordingly, clinical research on JHS/EDS-HT is moving from rheumatology and clinical genetics to other disciplines, including neurology, clinical psychology, ophthalmology, cardiology and gynecology/obstetrics. As the skin is one of the most commonly affected and, surely, the easiest to assess body part in heritable connective tissue disorders, it is expected that also the dermatologist should be trained to recognize this condition. In this review, JHS/EDS-HT is presented and discussed in separate sections dedicated to all major aspects of diagnosis, differential diagnosis, clinical features, natural history and principles of management. Particular attention is posed on the role of epidermal, dermal and mucosal assessment in JHS/EDS-HT is order to rise the attention to a series of too neglected, though quite common manifestations of this condition. Management principles are presented with a multidisciplinary approach in mind, covering pharmacologic, physical and occupational therapy, surgical, and nutriceutical aspects, as well as general lifestyle recommendations. Connections with organs and systems other than joints and skin are also discussed. PMID:23407074

  1. Realtime Multichannel System for Beat to Beat QT Interval Variability

    NASA Technical Reports Server (NTRS)

    Starc, Vito; Schlegel, Todd T.

    2006-01-01

    The measurement of beat-to-beat QT interval variability (QTV) shows clinical promise for identifying several types of cardiac pathology. However, until now, there has been no device capable of displaying, in real time on a beattobeat basis, changes in QTV in all 12 conventional leads in a continuously monitored patient. While several software programs have been designed to analyze QTV, heretofore, such programs have all involved only a few channels (at most) and/or have required laborious user interaction or offline calculations and postprocessing, limiting their clinical utility. This paper describes a PC-based ECG software program that in real time, acquires, analyzes and displays QTV and also PQ interval variability (PQV) in each of the eight independent channels that constitute the 12lead conventional ECG. The system also processes certain related signals that are derived from singular value decomposition and that help to reduce the overall effects of noise on the realtime QTV and PQV results.

  2. Four treatment strategies for complex regional pain syndrome type 1.

    PubMed

    Lee, Sang Ki; Yang, Dae Suk; Lee, Jae Won; Choy, Won Sik

    2012-06-01

    Complex regional pain syndrome (CRPS) poses a dilemma for many clinicians due to its unknown etiology and largely unsuccessful treatment modalities. The purpose of this study was to compare the clinical results of 4 treatment modalities for CRPS type 1. A total of 59 patients were divided into 4 groups based on treatment modality: group A, an oral nonsteroidal anti-inflammatory drug (NSAID) (n=10); group B, oral gabapentin (n=12); group C, intravenous (IV) 10% mannitol and steroid (n=11); group D, a combination of IV 20% mannitol and steroid with oral gabapentin (n=26). The patients remained under medical supervision after discharge and were evaluated either once a month or once every 2 months until final follow-up at a mean of 8 months. Patients in group A showed improvement in pain level, finger range of motion, swelling, and grip strength, without statistical significance (P=.076, P=.062, P=.312, and P=.804, respectively). Patients in group B showed significant improvement in pain level (P<.001), and patients in group C showed improvement in pain, finger range of motion, and swelling (P=.127), which rendered functional impairment unchanged. In comparison, patients in group D showed recovery of grip strength and improvement in pain level, finger range of motion, and (P<.001, P=.016, P=.031, and P=.047, respectively). Based on these results, a protocol including a combination of IV 20% mannitol and steroid with oral gabapentin is an acceptable and effective treatment for CRPS type 1. PMID:22691654

  3. Hearing dysfunction in heterozygous Mitf(Mi-wh) /+ mice, a model for Waardenburg syndrome type 2 and Tietz syndrome.

    PubMed

    Ni, Christina; Zhang, Deming; Beyer, Lisa A; Halsey, Karin E; Fukui, Hideto; Raphael, Yehoash; Dolan, David F; Hornyak, Thomas J

    2013-01-01

    The human deafness-pigmentation syndromes, Waardenburg syndrome (WS) type 2a, and Tietz syndrome are characterized by profound deafness but only partial cutaneous pigmentary abnormalities. Both syndromes are caused by mutations in MITF. To illuminate differences between cutaneous and otic melanocytes in these syndromes, their development and survival in heterozygous Microphthalmia-White (Mitf(Mi-wh) /+) mice were studied and hearing function of these mice characterized. Mitf(Mi-wh) /+ mice have a profound hearing deficit, characterized by elevated auditory brainstem response thresholds, reduced distortion product otoacoustic emissions, absent endocochlear potential, loss of outer hair cells, and stria vascularis abnormalities. Mitf(Mi-wh) /+ embryos have fewer melanoblasts during embryonic development than their wild-type littermates. Although cochlear melanocytes are present at birth, they disappear from the Mitf(Mi-wh) /+ cochlea between P1 and P7. These findings may provide insight into the mechanism of melanocyte and hearing loss in human deafness-pigmentation syndromes such as WS and Tietz syndrome and illustrate differences between otic and follicular melanocytes. PMID:23020089

  4. QT prolongation and torsades de pointes with psychotropic agents

    PubMed Central

    Desai, Nagaraj; Venkatesh, Chilkunda Raviprakash; Kumar, Shambu Sunil

    2015-01-01

    The unexpected and catastrophic cardiovascular effects of psychotropic drugs are well described albeit uncommon. The list of drugs which have been associated with prolonging QT interval and hence potentially causing Torsades de pointes is exhaustive. The insight into the plausible mechanisms are largely unclear. However, the practical implications of anticipating and recognizing QT prolongation cannot be overemphasized. PMID:26600587

  5. The Complex QT/RR Relationship in Mice

    PubMed Central

    Roussel, Julien; Champeroux, Pascal; Roy, Jérôme; Richard, Sylvain; Fauconnier, Jérémy; Le Guennec, Jean-Yves; Thireau, Jérôme

    2016-01-01

    The QT interval reflects the time between the depolarization of ventricles until their repolarization and is usually used as a predictive marker for the occurrence of arrhythmias. This parameter varies with the heart rate, expressed as the RR interval (time between two successive ventricular depolarizations). To calculate the QT independently of the RR, correction formulae are currently used. In mice, the QT-RR relationship as such has never been studied in conscious animals, and correction formulas are mainly empirical. In the present paper we studied how QT varies when the RR changes physiologically (comparison of nocturnal and diurnal periods) or after dosing mice with tachycardic agents (norepinephrine or nitroprusside). Our results show that there is significant variability of QT and RR in a given condition, resulting in the need to average at least 200 consecutive complexes to accurately compare the QT. Even following this method, no obvious shortening of the QT was observed with increased heart rate, regardless of whether or not this change occurs abruptly. In conclusion, the relationship between QT and RR in mice is weak, which renders the use of correction formulae inappropriate and misleading in this species. PMID:27138175

  6. QT dispersion in elderly athletes with left ventricular hypertrophy.

    PubMed

    Galetta, F; Franzoni, F; Santoro, G; Prattichizzo, F; Femia, F R; Pastine, F; Pentimone, F

    2003-05-01

    The purpose of this study was to examine the QT dispersion in elderly endurance athletes with left ventricular (LV) hypertrophy. Sixteen athletes (males, mean age 67.6 +/- 4.5 years) with mild to moderate LV hypertrophy, were compared with 16 age-matched hypertensive patients with similar degree of LV hypertrophy and 16 age-matched healthy sedentary controls. All the participants underwent echocardiogram and 12-lead electrocardiogram. QT dispersion was defined as the difference between maximum and minimum QT intervals in the different leads. QT dispersion was corrected (QTc) for heart rate according to Bazett's formula. The results showed in athletes and hypertensive patients comparable LV mass (258.2 +/- 14.2 vs. 262.4 +/- 16.8 g, ns), which was significantly higher than that of controls (p < 0.001). Trained subjects had QT dispersion (38.6 +/- 10.2 ms) and QTc dispersion (39.4 +/- 11.3 ms) significantly lower than hypertensive patients (QT dispersion: 68.4 +/- 11.4 ms; QTc dispersion: 72.2 +/- 8.4, p < 0.001) and comparable with controls (QT dispersion: 44.3 +/- 8.4 ms; QTc dispersion: 46.2 +/- 6.2 ms, ns). In conclusion, in elderly athletes training-induced myocardial hypertrophy was characterized by a QT dispersion significantly lower than hypertensive myocardial hypertrophy. This could provide a simple and inexpensive screening method for differentiating physiologic from pathologic myocardial hypertrophy in elderly subjects. PMID:12784163

  7. Rules for distinguishing toxicants that cause type I and type II narcosis syndromes

    SciTech Connect

    Veith, G.D.; Broderius, S.J. )

    1990-07-01

    Narcosis is a nonspecific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. The vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse aquatic organisms, using only the n-octanol/water partition coefficient as a descriptor. There are, however, many apparent narcotic chemicals that are more toxic than baseline narcosis predicts. Some of these chemicals have been distinguished as polar narcotics. Joint toxic theory and isobole diagrams were used to show that chemicals strictly additive with phenol were generally more toxic than predicted by narcosis I models and characterized by a different mode of action called narcosis II syndrome. This type of toxicity is exemplified by certain amides, amines, phenols, and nitrogen heterocycles. Evidence is provided that suggests that narcosis II syndrome may result from the presence of a strong hydrogen bonding group on the molecule, and narcosis I syndrome results from hydrophobic bonding of the chemical to enzymes and/or membranes. This shift in toxic action is apparently indistinguishable for narcotic chemicals with log P greater than about 2.7. General rules for selecting the appropriate models are proposed.

  8. Rules for distinguishing toxicants that cause type I and type II narcosis syndromes.

    PubMed

    Veith, G D; Broderius, S J

    1990-07-01

    Narcosis is a nonspecific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. The vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse aquatic organisms, using only the n-octanol/water partition coefficient as a descriptor. There are, however, many apparent narcotic chemicals that are more toxic than baseline narcosis predicts. Some of these chemicals have been distinguished as polar narcotics. Joint toxic theory and isobole diagrams were used to show that chemicals strictly additive with phenol were generally more toxic than predicted by narcosis I models and characterized by a different mode of action called narcosis II syndrome. This type of toxicity is exemplified by certain amides, amines, phenols, and nitrogen heterocycles. Evidence is provided that suggests that narcosis II syndrome may result from the presence of a strong hydrogen bonding group on the molecule, and narcosis I syndrome results from hydrophobic bonding of the chemical to enzymes and/or membranes. This shift in toxic action is apparently indistinguishable for narcotic chemicals with log P greater than about 2.7. General rules for selecting the appropriate models are proposed. PMID:2269227

  9. Genetic heterogeneity of usher syndrome type 1 in French families

    SciTech Connect

    Larget-Piet, D.; Gerber, S.; Rozet, J.M. ); Bonneau, D. ); Marc, S.; Weissenbach, J. ); Ghazi, I.; Dufier, J.L. ); David, A. ); Bitoun, P. )

    1994-05-01

    Usher syndrome type 1 (US1) is an autosomal recessive disease characterized by profound congenital hearing impairment with unintelligible speech, early retinitis pigmentosa, and constant vestibular dysfunction. Three localizations have been described in US1: USH1A, 14q32; USH1B, 11q13.5; and USH1C, 11p15. Studying a series of 33 affected individuals belonging to 20 US1 pedigrees of French ancestry, the authors found that none of the three localizations accounted for all US1 families in the series. However, when the sample was split into two groups according to the geographic origin of the probands' grandparents, they were able to confirm the presence of a gene for US1 on chromosome 14q32 (USH1A) in 9 families originating from the Poitou region in Western France. Moreover, they refined the genetic mapping of USH1A by showing that the disease gene maps to the D14S13 locus, within the genetic interval defined by loci D14S78 and D14S250 (location score in log base 10 = 4.90). Consistent with this, nonsignificant lod score values for linkage to either USH1B or USH1C were found in this group. With regard to US1 families of other geographic origin (Normandy and Northern France, 11 families), nonsignificant lod scores for linkage to chromosome 11q13.5 were observed. However, the HOMOG test suggested that USH1B might account for the disease in 9/11 families in the series (families 10-19), the latter two families possibly being accounted for by USH1C (maximum likelihood for heterogeneity = 7.91 in lnL; heterogeneity versus homogeneity, P = 0.01; heterogeneity versus nonlinkage, P < 0.01). The present study supports the view that Usher syndrome type 1 is a genetically heterogeneous condition that is caused by at least three genes and possibly many more. 16 refs., 4 figs., 3 tabs.

  10. Prevalence of metabolic syndrome in type 2 diabetes mellitus patients

    PubMed Central

    Nsiah, Kwabena; Shang, V Owusua; Boateng, K Agyenim; Mensah, FO

    2015-01-01

    Background: The diabetic condition is influenced by several factors, some of which can accelerate the disease's progression to various complications that aggravate the morbidity. Aims: This study aimed at determining the prevalence of metabolic syndrome (MetS) and its individual components and the most critical predictive risk factors of MetS in type 2 diabetic patients. Materials and Methods: This cross-sectional study involved 150 type 2 diabetes mellitus patients and was conducted at the Diabetes Centre of the Komfo Anokye Teaching Hospital in Kumasi, the Ashanti Region of Ghana, from February, 2013 to April, 2013. The study involved the use of a questionnaire to obtain some information on the diabetics, undertaking anthropometric measurements, as well as collecting blood samples for the measurement of some biochemical parameters; fasting blood glucose and lipid profile. MetS was defined according to the National Cholesterol Education Program/Adult Treatment Panel III criteria. Results: The prevalence of MetS was 58% in the studied Ghanaian population. Hypertension was the commonest risk factor (60%), followed by central obesity (48.67%) and dyslipidemia (37%). Female type 2 diabetics had a higher prevalence of MetS, and carried more components than their male counterparts. Regression analysis showed three factors; femininity, high body mass index and low educational status were the most critical predictive risk factors of MetS, according to this study. Conclusion: With hypertension being the commonest component, future cardiovascular disease prevention strategies should focus attention on its management and prevention, through education. PMID:26097823

  11. Analysis of HLA and disease susceptibility: Chromosome 6 genes and sex influence long-QT phenotype

    SciTech Connect

    Weitkamp, L.R.; Moss, A.J.; Hall, W.J.; Robinson, J.L.; Guttormsen, S.A.; Lewis, R.A.; MacCluer, J.W.; Schwartz, P.J.; Locati, E.H.; Tzivoni, D.

    1994-12-01

    The long-QT (LQT) syndrome is a genetically complex disorder that is characterized by syncope and fatal ventricular arrhythmias. LQT syndrome, as defined by a prolonged electrocardiographic QT interval, has a higher incidence in females than in males and does not exhibit Mendelian transmission patterns in all families. Among those families that are nearly consistent with Mendelian transmission, linkage between a locus for LQT syndrome and the H-ras-1 locus on the short arm of chromosome 11 has been reported in some families but not in others. Earlier analyses suggesting that LQT syndrome might be caused by a gene in the HLA region of chromosome 6 were not confirmed by standard linkage analyses. Here, we present an analysis of HLA haplotype sharing among affected pedigree members, showing an excess of haplotype sharing in a previously published Japanese pedigree and possibly also in 15 families of European descent. The haplotypes shared by affected individuals derive from both affected and unaffected parents. In an analysis of independent (unrelated) HLA haplotypes, we also found a nonrandom distribution of HLA-DR genes in LQT syndrome patients compared with controls, suggesting an association between the LQT phenotype and specific HLA-DR genes. Our data indicate that DR2 has a protective effect and, particularly in males, that DR7 may increase susceptibility to the LQT syndrome. Thus, LQT syndrome may be influenced by genes on chromosomes 11 and 6, possibly with a sex-specific effect. These results provide a model for an effect of HLA-region genes inherited from either parent on the expression of an illness that may be determined principally by alleles at loci not linked to HLA.

  12. Partially dominant mutant channel defect corresponding with intermediate Long-QT2 phenotype

    PubMed Central

    Krishnan, Yamini; Zheng, Renjian; Walsh, Christine; Tang, YingYing; McDonald, Thomas V.

    2011-01-01

    Background The hereditary Long QT Syndrome (LQTS) is a common cardiac disorder where ventricular repolarization is delayed, abnormally prolonging the QTc interval on ECG. LQTS is linked to various genetic loci including the KCNH2 (HERG) gene that encodes the α–subunit of the cardiac potassium channel that carries IKr. Here we report and characterize a novel pathologic missense mutation, G816V HERG, in a patient with sudden cardiac death. Methods Autopsy-derived tissue sample was used for DNA extraction and sequencing from an unexpected sudden death victim. The G816V HERG mutation was studied using heterologous expression in mammalian cell culture, whole cell patch clamp, confocal immunofluorescence, and immunochemical analyses. Results The mutant G816V HERG channel has reduced protein expression and shows a trafficking defective phenotype that is incapable of carrying current when expressed at physiological temperatures. The mutant channel showed reduced cell surface localization compared to wild-type HERG (WT HERG) but the mutant and wild-type subunits are capable of interacting. Expression studies at reduced temperatures enabled partial rescue of the trafficking defect with appearance of potassium currents albeit with reduced current density and altered voltage-dependent activation. Lastly, we examined a potential role for hypokalemia as a contributory factor to the patient’s lethal arrhythmia by possible low-potassium induced degradation of WT HERG and haplo-insufficiency of G816V HERG. Conclusion The G816V mutation in HERG causes a trafficking defect which acts in a partially dominant-negative manner. This intermediate severity defect agrees with the mild clinical presentation in other family members harboring the same mutation. Possible hypokalemia in the proband induced WT HERG degradation combined with haplo-insufficiency may have further compromised repolarization reserve and contributed to the lethal arrhythmia. PMID:21951015

  13. Evidence based guidelines for complex regional pain syndrome type 1

    PubMed Central

    2010-01-01

    Background Treatment of complex regional pain syndrome type I (CRPS-I) is subject to discussion. The purpose of this study was to develop multidisciplinary guidelines for treatment of CRPS-I. Method A multidisciplinary task force graded literature evaluating treatment effects for CRPS-I according to their strength of evidence, published between 1980 to June 2005. Treatment recommendations based on the literature findings were formulated and formally approved by all Dutch professional associations involved in CRPS-I treatment. Results For pain treatment, the WHO analgesic ladder is advised with the exception of strong opioids. For neuropathic pain, anticonvulsants and tricyclic antidepressants may be considered. For inflammatory symptoms, free-radical scavengers (dimethylsulphoxide or acetylcysteine) are advised. To promote peripheral blood flow, vasodilatory medication may be considered. Percutaneous sympathetic blockades may be used to increase blood flow in case vasodilatory medication has insufficient effect. To decrease functional limitations, standardised physiotherapy and occupational therapy are advised. To prevent the occurrence of CRPS-I after wrist fractures, vitamin C is recommended. Adequate perioperative analgesia, limitation of operating time, limited use of tourniquet, and use of regional anaesthetic techniques are recommended for secondary prevention of CRPS-I. Conclusions Based on the literature identified and the extent of evidence found for therapeutic interventions for CRPS-I, we conclude that further research is needed into each of the therapeutic modalities discussed in the guidelines. PMID:20356382

  14. Risk of Restless Legs Syndrome Following Tension-Type Headache

    PubMed Central

    Yang, Fu-Chi; Lin, Te-Yu; Chen, Hsuan-Ju; Lee, Jiunn-Tay; Lin, Chun-Chieh; Kao, Chia-Hung

    2015-01-01

    Abstract Migraine and restless legs syndrome (RLS) appear to be associated, but the relationship between tension-type headache (TTH) and RLS is unknown. This nationwide, population-based, retrospective cohort study explored the potential association between TTH and RLS. We identified 15,504 patients with newly diagnosed TTH from 2000 to 2007 and 62,016 individuals without TTH who were selected by frequency matched based on sex, age, and the index year. The study participants were followed until diagnosed with RLS, withdrawal from the NHI program, or the end of 2011. Cox proportional hazard models were used to identify risk factors for RLS in TTH patients. After adjusting for sex, age, comorbidity, and medications, TTH was significantly associated with an increased risk of RLS (hazard ratio [HR] = 1.57, 95% confidence interval [CI] = 1.22–2.02). The risk was most prominent in patients aged 20 to 39 years in the TTH group, which exhibited a 2.60-fold higher risk (95% confidence interval = 1.53–4.42) of RLS compared with the non-TTH group. The TTH group had a higher risk of RLS than that of the non-TTH group regardless of sex. Tension-type headache appears to be associated with an increased risk of developing RLS. This similarity to migraines may indicate that headache and RLS have a coincident pathophysiological mechanism, a possibility requiring further study. Clinicians should be more attentive to RLS as a possible comorbidity in patients with TTH. PMID:26579827

  15. Crooked fingers and sparse hair: an interesting case of trichorhinophalangeal syndrome type 1.

    PubMed

    Narayanan, Ramakrishna; Chennareddy, Srinivasa

    2015-01-01

    Trichorhinophalangeal syndrome type 1 is a rare skeletal dysplasia of autosomal-dominant inheritance due to defects in the TRPS-1 gene. The syndrome is characterised by sparse slow-growing hair, a bulbous pear-shaped nose, cone-shaped epiphyses and deformities of the interphalangeal joints resembling those in rheumatoid arthritis. We present a case of trichorhinophalangeal syndrome in a 23-year-old man who presented with symmetrical painless progressive deformity of the fingers in both hands. PMID:25628322

  16. Mucopolysaccharidosis type I Hurler-Scheie syndrome: A rare case report.

    PubMed

    Tatapudi, Ramesh; Gunashekhar, M; Raju, P Suryanarayana

    2011-01-01

    Mucopolysaccharidosis I (MPS I) is a rare inherited disorder that belongs to a group of clinically progressive disorders and is caused by the deficiency of the lysosomal enzyme, α(1)-iduronidase. MPS I has been recently classified into a severe (Hurler syndrome) and an attenuated type (Hurler-Scheie and Scheie syndromes). The purpose of this article was to describe a rare case of MPS type I, attenuated type (Hurler-Scheie) affecting a 15-year-old Indian child. PMID:22114460

  17. Complex regional pain syndrome type 1 in a pediatric patient: Case report

    PubMed Central

    Demirdal, Ümit Seçil; Bükülmez, Ayşegül; Solak, Özlem

    2014-01-01

    Complex regional pain syndrome type 1 is one of the causes of morbidity of childhood which is also named reflex symphathetic dystrophia. The syndrome is characterized with regional pain and vasomotor, sudomotor and sensory changes in the distal parts of the extremities involved. Complex regional pain syndrome type 1 shows difference in children in terms of clinical picture and imaging methods compared to adults. The most important point is that the prognosis is generally better in children if early diagnosis and treatment is provided. On the other hand, causes including presence of psychological factors or less contribution of imaging methods in children lead to delayed diagnosis or erroneous diagnosis. In this article, a 10 year-old male patient who was diagnosed with complex regional pain syndrome type 1 was described. Thus, we aimed to remind clinicians that this syndrome should also be kept in mind in the differential diagnosis of pain in children. PMID:26078637

  18. Type 1 diabetes: Syndromes in resource-challenged settings.

    PubMed

    Nagesh, V Sri; Kalra, Sanjay

    2015-06-01

    Type 1 Diabetes is a complex disorder that is made more complex by the myriad of co-morbid conditions associated with it. Mauriac Syndrome is a well-known but nowadays uncommon condition that presents with growth retardation secondary to poor glycaemic control. Limited Joint Mobility is an often-missed association of diabetes. Its importance lies in the fact that it can cause significant impairment of fine movements in T1DM children. It also indicates poor glycaemic control over a long period of time and can be used as a surrogate marker for development of diabetic microvascular complications. Anaemia in T1DM is protean and can develop due to a combination of nutritional factors, chronic renal disease, coeliac disease and worm infestation. Management is etiological. Vitamin deficiencies are ubiquitous in T1DM and if left untreated, can lead to neurological, haematological and skeletal dysfunction. The best-known co-morbid conditions are the local site reactions clubbed together under the moniker lipodystrophies. These can be either atrophic or hypertrophic and are usually due to repeated injections at the same site, improper technique and needle re-use. Management is often difficult and they are best prevented by appropriate diabetes education and emphasis on proper injection techniques at the time of T1DM diagnosis, with periodic reinforcement. Amyloidosis is a little known condition that shares a lot of features in common with the lipodystrophies and often needs to be differentiated from lipohypertrophy. T1DM is a disease which is often associated with a poor quality of life and these co-morbid conditions also need to be treated for effective general and psychological well-being. PMID:26060173

  19. Management of patients with complex regional pain syndrome type I.

    PubMed

    Gatti, D; Rossini, M; Adami, S

    2016-08-01

    Complex regional pain syndrome type I (CRPS-I) includes different conditions characterized by regional pain and sensory, motor, sudomotor, vasomotor, and/or trophic findings, affecting a peripheral limb usually after a noxious event, such as a trauma or surgery. The pathophysiology is still poorly understood. Limited data are available on the incidence of CRPS-I, and the disease is underestimated and under-diagnosed. The disease shows a female preponderance approximately 3:1 with a peak age of incidence around the 5th and 6th decade. The available diagnostic criteria for CRPS-I rely on clinical criteria that are unfortunately focused on the signs and symptoms of the chronic and late disease, while little emphasis is given to the typical imaging (X-rays, bone scintigraphy, MRI) findings of the early phase. Over the last decades, several therapies have been proposed but the few studies available are often too small to be conclusive and rarely evolved to randomized controlled trials (RCTs). On the basis of the results of a few RCTs, only short courses of high bisphosphonate doses appear to provide substantial benefits. The best results are seen in patients in the early phase of the disease, often with the persistent remission or complete healing of the conditions. Since the only accredited mechanism of action of bisphosphonates is the suppression of osteoclastic bone resorption, it is likely the initial dramatic bone loss plays a role in the maintenance and evolution of CRPS-I. Short courses of high doses of bisphosphonates should be considered the treatment of choice for patients with CRPS-I. PMID:26928187

  20. Screening of three Usher syndrome type II candidate genes

    SciTech Connect

    Bloemker, B.K.; Swaroop, A.; Kimberling, W.J.

    1994-09-01

    Usher syndrome type II (US2) is an autosomal recessive disorder that results in blindness due to retinitis pigmentosa and congenital hearing loss. The disease affects approximately 1 in 20,000 individuals in the general population and is responsible for over 50% of all cases of deafness with blindness. The underlying US2 defect is unknown. The US2 gene has been localized to the 1q41 region of chromosome 1 by linkage studies. Three genes previously localized to 1q were analyzed to assess their candidacy as the US2 gene. These were evaluated by PCR assays using DNA from a YAC contig spanning the US2 region on chromosome 1. The first gene evaluated was the human choroideremia-like gene (hCHML), which had been mapped to chromosome 1q. The sequence on 1q is a homologue of the human choroideremia gene on chromosome X. Choroideremia is a degenerative disorder causing ocular pathology similar to that observed in US2 patients. Therefore, hCHML is a candidate for the US2 gene. Two cDNAs (A and B) from an enriched human retinal pigment epithelium library have been mapped to 1q41 by in situ hybridization. Both cDNAs are considered good candidates. The hCHML and cDNA A were ruled out as candidates for the US2 gene based on negative results from PCR assays performed on YACs spanning the US2 region. cDNA B could not be ruled out as a candidate for the US2 gene by these assays. Answers to many clinical questions regarding US2 will only be resolved after the gene is identified and characterized. Eventually, understanding the function and expression of the US2 gene will provide a basis for the development of therapy.

  1. Characterization of a recombination event excluding the Harvey-ras-1 (H-ras-1) locus in a Ramano-Ward Long QT syndrome family linked to Chromosome 11q15 and isolation of a polymorphic repeat telomeric to H-ras-1

    SciTech Connect

    Russell, M.W.; Brody, L.C.; Munroe, D.

    1994-09-01

    The Romano-Ward Long QT syndrome (RWLQTS) has been linked to 11p15.5 in several large families but demonstrates genetic heterogeneity, since in other families the RWLQTS phenotype is not linked to 11p15. To date, no recombinants between the H-Ras-1 locus and RWLQTS in families linked to 11p15 have been published. In a large family, we demonstrate linkage of RWLQTS to marker D11S932 on chromosome 11p15.4 with a LOD score of 3.14 ({theta}=0;90% penetrance). An unaffected individual and her two unaffected offspring inherited the affected haplotype for the H-ras-1 region telomeric to D11S932. All three have QTc measurements of {le} 0.40 seconds and no history of syncope, making the diagnosis of RWLQTS extremely unlikely. This suggests that, although the gene for the RWlQTS is linked to 11p15 in this family, a recombination event may have occurred that separated the RWLQTS gene from the affected H-ras-1 region haplotype. To investigate a possible telomeric recombination event, cosmids telomeric to H-ras-1 were isolated. A highly polymorphic, complex CA/CT repeat marker (78% heterozygosity) was characterized and its location telomeric to H-ras-1 verified by interphase FISH. The same three unaffected individuals had the affected allele for this marker, ruling our recombination telomeric to H-ras-1 but proximal to the new marker. As the most telemeric marker on 11p to date, this marker will aid the physical and genetic mapping of the 11p telomere. The potential recombination event in this family apparently excludes H-ras-1 as a candidate gene and may aid the localization of the RWLQTS gene linked to 11p15.5. However, it remains a possibility that another genetic locus on 11p15, in addition to the one near the H-ras-1 gene, can cause the RWLQTS phenotype. This is the first report of recombination between H-ras-1 and RWLQTS in a family linked to 11p15.

  2. Giant bladder diverticulum in Ehlers-Danlos syndrome type I causing outflow obstruction.

    PubMed

    Burrows, N P; Monk, B E; Harrison, J B; Pope, F M

    1998-05-01

    We describe a 16-year-old patient with Ehlers-Danlos syndrome (EDS) type I and recurrent urinary retention caused by giant bladder diverticulum and review the literature on this association. PMID:9861737

  3. [Potassium channelopathies and Morvan's syndromes].

    PubMed

    Serratrice, Georges; Pellissier, Jean-François; Serra-Trice, Jacques; Weiller, Pierre-Jean

    2010-02-01

    Interest in Morvan's disease or syndrome has grown, owing to its close links with various potassium channelopathies. Potassium is crucial for gating mechanisms (channel opening and closing), and especially for repolarization. Defective potassium regulation can lead to neuronal hyperexcitability. There are three families of potassium channels: voltage-gated potassium channels or VGKC (Kv1.1-Kv1.8), inward rectifier K+ channels (Kir), and two-pore channels (K2p). VGK channels are the commonest, and especially those belonging to the Shaker group (neuromyotonia and Morvan's syndrome, limbic encephalitis, and type 1 episodic ataxia). Brain and heart K+ channelopathies are a separate group due to KCNQ1 mutation (severe type 2 long QT syndrome). Kv7 channel mutations (in KNQ2 and KCNQ3) are responsible for benign familial neonatal seizures. Mutation of the Ca+ activated K+ channel gene causes epilepsy and paroxysmal dyskinesia. Inward rectifier K+ channels regulate intracellular potassium levels. The DEND syndrome, a treatable channelopathy of the brain and pancreas, is due to KCNJ1 mutation. Andersen's syndrome, due to KCNJ2 mutation, is characterized by periodic paralysis, cardiac arrythmia, and dysmorphia. Voltage-insensitive K2p channelopathies form a final group. PMID:21166127

  4. The pathogenesis of the clinical features of oral-facial-digital syndrome type I

    PubMed Central

    AlKattan, Wael M.; Al-Qattan, Mohammad M.; Bafaqeeh, Sameer A.

    2015-01-01

    Oral-facial-digital syndrome type I (OFDI) is an X-linked syndrome, which has several craniofacial and limb features; and hence, patients frequently present to craniofacial and plastic surgeons. Oral-facial-digital syndrome type I is caused by mutations in the CXORF5 gene. The gene product is one of the basal body proteins of a slim microtubule-based organelle called the “primary cilium”. Most of the clinical features of OFDI patients are related to dysfunctions of the primary cilium leading to abnormal Hedgehog signal transduction, depressed planar cell polarity pathway, and errors in cell cycle control. PMID:26593159

  5. Semen analysis in the Usher syndrome type 2A.

    PubMed

    van Aarem, A; Wagenaar, M; Tonnaer, E; Pieke Dahl, S; Bisseling, J; Janssen, H; Bastiaans, B; Kimberling, W; Cremers, C

    1999-01-01

    Semen analysis in patients with Usher syndrome suggested that defective connecting cilia axonemes may be involved in the irreversible, progressive loss of photoreceptors in Usher's syndrome. In the framework of clinical genetic research into Usher syndrome, a pilot study was set up to test these findings. The semen of 6 Usher 2A patients was analysed. The fertility status of the study group of Usher 2A patients was evaluated, including semen analysis, supplemented by electron microscopic examination of the spermatozoa. Except for a significantly increased pH value, no abnormalities were found in the functional semen analysis, whereas electron microscopy revealed microtubular tail abnormalities. The latter finding was of little relevance, however, in view of the normal motility of the spermatozoa observed in these patients. There were no fertility problems in our group of Usher 2A patients, nor have any been mentioned in Usher patients in general. Earlier study findings were not supported by our data. PMID:10325550

  6. Type IV Ehlers-Danlos Syndrome: A Surgical Emergency? A Case of Massive Retroperitoneal Hemorrhage.

    PubMed

    Chun, Stephen G; Pedro, Patrick; Yu, Mihae; Takanishi, Danny M

    2011-01-01

    Retroperitoneal hemorrhagic bleeding is a known manifestation of Type-IV Ehlers-Danlos Syndrome that is caused by loss-of-function mutations of the pro-alpha-1 chains of type III pro-collagen (COL3A1) resulting in vascular fragility. A number of previous reports describe futile surgical intervention for retroperitoneal bleeding in Type-IV Ehlers-Danlos Syndrome with high post-operative mortality, although the rarity of retroperitoneal bleeding associated with Type-IV Ehlers-Danlos Syndrome precludes an evidence-based approach to clinical management. We report a 23-year-old male with history of Type-IV Ehlers-Danlos Syndrome who presented with severe abdominal pain and tachycardia following an episode of vomiting. Further work-up of his abdominal pain revealed massive retroperitoneal bleeding by CT-scan of the abdomen. Given numerous cases of catastrophic injury caused by surgical intervention in Type-IV Ehlers-Danlos Syndrome, the patient was treated non-operatively, and the patient made a full recovery. This case suggests that even in cases of large retroperitoneal hemorrhages associated with Ehlers-Danlos Syndrome, it may not truly represent a surgical emergency. PMID:21966332

  7. Pharmacological approach to the treatment of long and short QT syndromes☆

    PubMed Central

    Patel, Chinmay; Antzelevitch, Charles

    2008-01-01

    Inherited channelopathies have received increasing attention in recent years. The past decade has witnessed impressive progress in our understanding of the molecular and cellular basis of arrhythmogenesis associated with inherited channelopathies. An imbalance in ionic forces induced by these channelopathies affects the duration of ventricular repolarization and amplifies the intrinsic electrical heterogeneity of the myocardium, creating an arrhythmogenic milieu. Today, many of the channelopathies have been linked to mutations in specific genes encoding either components of ion channels or membrane or regulatory proteins. Many of the channelopathies are genetically heterogeneous with a variable degree of expression of the disease. Defining the molecular basis of channelopathies can have a profound impact on patient management, particularly in cases in which genotype-specific pharmacotherapy is available. The long QT syndrome (LQTS) is one of the first identified and most studied channelopathies where abnormal prolongation of ventricular repolarization predisposes an individual to life threatening ventricular arrhythmia called Torsade de Pointes. On the other hand of the spectrum, molecular defects favoring premature repolarization lead to Short QT syndrome (SQTS), a recently described inherited channelopathy. Both of these channelopathies are associated with a high risk of sudden cardiac death due to malignant ventricular arrhythmia. Whereas pharmacological therapy is first line treatment for LQTS, defibrillators are considered as primary treatment for SQTS. This review provides a comprehensive review of the molecular genetics, clinical features, genotype–phenotype correlations and genotype-specific approach to pharmacotherapy of these two mirror-image channelopathies, SQTS and LQTS. PMID:18378319

  8. Impact of Human Immunodeficiency Virus Type 1 (HIV-1) Genetic Diversity on Performance of Four Commercial Viral Load Assays: LCx HIV RNA Quantitative, AMPLICOR HIV-1 MONITOR v1.5, VERSANT HIV-1 RNA 3.0, and NucliSens HIV-1 QT

    PubMed Central

    Swanson, Priscilla; de Mendoza, Carmen; Joshi, Yagnya; Golden, Alan; Hodinka, Richard L.; Soriano, Vincent; Devare, Sushil G.; Hackett, John

    2005-01-01

    Human immunodeficiency virus type 1 (HIV-1) evolution and changing strain distribution present a challenge to nucleic acid-based assays. Reliable patient monitoring of viral loads requires the detection and accurate quantification of genetically diverse HIV-1. A panel of 97 HIV-1-seropositive plasma samples collected from Cameroon, Brazil, and South Africa was used to compare the performance of four commercially available HIV RNA quantitative tests: Abbott LCx HIV RNA Quantitative assay (LCx), Bayer Versant HIV-1 RNA 3.0 (bDNA), Roche AMPLICOR HIV-1 MONITOR v1.5 (Monitor v1.5), and bioMérieux NucliSens HIV-1 QT (NucliSens). The panel included group M, group O, and recombinant viruses based on sequence analysis of gag p24, pol integrase, and env gp41. The LCx HIV assay quantified viral RNA in 97 (100%) of the samples. In comparison, bDNA, Monitor v1.5, and NucliSens quantified viral RNA in 96.9%, 94.8%, and 88.6% of the samples, respectively. The two group O specimens were quantified only by the LCx HIV assay. Analysis of nucleotide mismatches at the primer/probe binding sites for Monitor v1.5, NucliSens, and LCx assays revealed that performance characteristics reflected differences in the level of genetic conservation within the target regions. PMID:16081923

  9. 15 YEARS OF PARAGANGLIOMA: Clinical manifestations of paraganglioma syndromes types 1–5

    PubMed Central

    Benn, Diana E; Robinson, Bruce G; Clifton-Bligh, Roderick J

    2015-01-01

    The paraganglioma (PGL) syndromes types 1–5 are autosomal dominant disorders characterized by familial predisposition to PGLs, phaeochromocytomas (PCs), renal cell cancers, gastrointestinal stromal tumours and, rarely, pituitary adenomas. Each syndrome is associated with mutation in a gene encoding a particular subunit (or assembly factor) of succinate dehydrogenase (SDHx). The clinical manifestations of these syndromes are protean: patients may present with features of catecholamine excess (including the classic triad of headache, sweating and palpitations), or with symptoms from local tumour mass, or increasingly as an incidental finding on imaging performed for some other purpose. As genetic testing for these syndromes becomes more widespread, presymptomatic diagnosis is also possible, although penetrance of disease in these syndromes is highly variable and tumour development does not clearly follow a predetermined pattern. PGL1 syndrome (SDHD) and PGL2 syndrome (SDHAF2) are notable for high frequency of multifocal tumour development and for parent-of-origin inheritance: disease is almost only ever manifest in subjects inheriting the defective allele from their father. PGL4 syndrome (SDHB) is notable for an increased risk of malignant PGL or PC. PGL3 syndrome (SDHC) and PGL5 syndrome (SDHA) are less common and appear to be associated with lower penetrance of tumour development. Although these syndromes are all associated with SDH deficiency, few genotype–phenotype relationships have yet been established, and indeed it is remarkable that such divergent phenotypes can arise from disruption of a common molecular pathway. This article reviews the clinical presentations of these syndromes, including their component tumours and underlying genetic basis. PMID:26273102

  10. A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis.

    PubMed

    Baab, Karen L; Brown, Peter; Falk, Dean; Richtsmeier, Joan T; Hildebolt, Charles F; Smith, Kirk; Jungers, William

    2016-01-01

    The Liang Bua hominins from Flores, Indonesia, have been the subject of intense scrutiny and debate since their initial description and classification in 2004. These remains have been assigned to a new species, Homo floresiensis, with the partial skeleton LB1 as the type specimen. The Liang Bua hominins are notable for their short stature, small endocranial volume, and many features that appear phylogenetically primitive relative to modern humans, despite their late Pleistocene age. Recently, some workers suggested that the remains represent members of a small-bodied island population of modern Austro-Melanesian humans, with LB1 exhibiting clinical signs of Down syndrome. Many classic Down syndrome signs are soft tissue features that could not be assessed in skeletal remains. Moreover, a definitive diagnosis of Down syndrome can only be made by genetic analysis as the phenotypes associated with Down syndrome are variable. Most features that contribute to the Down syndrome phenotype are not restricted to Down syndrome but are seen in other chromosomal disorders and in the general population. Nevertheless, we re-evaluated the presence of those phenotypic features used to support this classification by comparing LB1 to samples of modern humans diagnosed with Down syndrome and euploid modern humans using comparative morphometric analyses. We present new data regarding neurocranial, brain, and symphyseal shape in Down syndrome, additional estimates of stature for LB1, and analyses of inter- and intralimb proportions. The presence of cranial sinuses is addressed using CT images of LB1. We found minimal congruence between the LB1 phenotype and clinical descriptions of Down syndrome. We present important differences between the phenotypes of LB1 and individuals with Down syndrome, and quantitative data that characterize LB1 as an outlier compared with Down syndrome and non-Down syndrome groups. Homo floresiensis remains a phenotypically unique, valid species with its roots