Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Long QT syndrome (LQT) is a cardiac disorder that causes sudden death from ventricular tachyarrhythmias, specifically torsade de pointes. Two types of LQT have been reported, autosomal-dominant LQT (Romano-Ward syndrome) and autosomal-recessive LQT (Jervell and Lange-Nielsen syndrome); Jervell and Lange-Nielsen syndrome is also associated with deafness. Four LQT genes have been identified for autosomal-dominant LQT: K+ channel genes KVLQT1 on chromosome 11p15.5, HERG on 7q35-36 and minK on 21q22, and the cardiac Na+ channel gene SCN5A on chromosome 3p21-24. Two genes, KVLQT1 and minK, have been identified for Jervell and Lange-Nielsen syndrome. Genetic testing and gene-specific therapies are available for some LQT patients.
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PMID:The molecular basis of long QT syndrome and prospects for therapy. 979 61

The long QT syndrome (LQTS) is a heart disorder which is characterised by the prolongation of the QT interval of the surface electrocardiogram and is associated with malignant arrhythmias, syncopal episodes, torsade de pointes form ventricular tachycardias and an increased risk of sudden cardiac death. There are two familial forms of LQTS, the autosomal dominant Romano-Ward syndrome and the autosomal recessive Jervell-Lange-Nielsen syndrome which is associated with congenital senzorineural deaf-mutism. Recent advances in molecular genetics have allowed to identify mutations in four genes, KvLQT1 (11p15.5), HERG (7q35), SCN5A (3p21) and minK (21q22), which cause LQTS. There is a fifth genetic locus known on chromosome 4 (4q25-27), where the disease causing gene has not been identified yet. As LQTS genes code proteins which form sodium and potassium channels of the heart, LQTS can be regarded as the disease of cardiac ion channels. The KvLQT1 and minK genes code the slowly activating, delayed rectifier (Iks) potassium channel, the HERG gene code the rapidly activating, delayed rectifier (Ikr) potassium channel of the heart, while the SCN5A gene codes a cardiac sodium channel. Mutations in KvLQT1, minK and HERG genes affects repolarising, rectifier potassium currents, while SCN5A mutations cause delayed inactivation and reopening of the cardiac sodium channel, which initiates the depolarisation of cardiac cells. Both alterations result in a prolongation of cardiac repolarisation which is represented in the elongation of the QT interval. Elucidation of the genetic base of the disease provided new tools in the clinical management of LQTS. It has been shown that changes in the repolarisation parameters on the ECG may be predictive for the causative gene and different LQTS genes are associated with different clinical picture. More importantly, it is possible to use "gene-specific" therapy in LQTS which specifically targets ion channels affected by given gene mutations.
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PMID:[Molecular genetics of the long QT syndrome: clinical aspects]. 1061 47

The prolonged QT syndromes are characterized by prolongation of the QT interval corrected for heart rate (QTc) on the surface electrocardiogram associated with T-wave abnormalities, relative bradycardia, and ventricular tachyarrhythmias, including polymorphic ventricular tachycardia and torsades de pointes. These patients tend to present with episodes of syncope, seizures, or sudden death typically triggered by exercise, emotion, noise, or, in some cases, sleep. These disorders of cardiac repolarization are commonly inherited, with the autosomal dominant form, Romano-Ward syndrome, most common. A rare autosomal recessive form associated with sensorineural deafness, Jervell and Lange-Nielsen syndrome, in which the cardiac disorder is autosomal dominant and deafness is a recessive trait, also occurs. The underlying genetic causes of these forms of prolonged QT interval syndromes are heterogeneous, with at least seven genes responsible for the clinical syndromes. All of the five genes identified to date encode ion channel proteins, suggesting this to be an ion channelopathy. In this review, the genetic basis of the prolonged QT interval syndromes will be discussed, genotype-phenotype correlations identified, and the approaches to genetic testing and treatments will be outlined.
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PMID:Molecular biology and the prolonged QT syndromes. 1128 54

Jervell, Lange-Nielsen syndrome is a condition that causes profound hearing loss and disruption of the normal cardiac rhythm. This disorder is a form of long QT syndrome, a cardiac disorder that causes the cardiac muscle to take longer than usual to recharge between beats. A retrospective case study was performed to document cochlear implantation in three profoundly deaf children (two of them siblings) with Jervell, Lange-Nielsen syndrome. We discuss diagnosis and management of this syndrome and also the long-term performance of cochlear implantation in these Iranian patients, referring especially to the role of the ENT specialist in diagnosis and treatment. The collected data show that cochlear implantation can be relatively safely performed in patients with Jervell, Lange-Nielsen syndrome and that these children received significant benefit from cochlear implantation.
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PMID:Cochlear implantation in children with Jervell, Lange-Nielsen syndrome. 1749 28

Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder with a disturbance in repolarization characterized by a prolonged QT interval on the surface electrocardiogram and life-threatening ventricular tachycardia. Publications from the International LQTS Registry have provided information that the cardiac risk may be influenced by gender, genotype, exposure to arrhythmia triggers, and previous cardiac events. In children, early-onset of disease, changes in life style, and medical treatment is a sensitive issue and significant, gender-related differences of a first life-threatening event were reported. Thus, we investigated the clinical features of a large genotyped population of LQTS-index children (age < or =16 years) upon a single-center experience and determined risk factors for symptoms. Of 83 children [mean corrected QT interval (QTc) 510 +/- 74 ms], 89% had LQT1, -2, or -3. Nine patients (11%) were identified as having Jervell and Lange-Nielsen syndrome. Among symptomatic children (n = 51, 61%), syncope was the most prevalent symptom at initial presentation (49%); however, aborted cardiac arrest (ACA) occurred in 33% and sudden cardiac death (SCD) in 18%, respectively, as the initial manifestation. During a mean follow-up period of 5.9 +/- 4.7 years, 31% of the children developed symptoms while on therapy (86% syncope, 9% ACA, 5% SCD). Statistical analyses of risk factors for cardiac events showed that the QTc >500 ms was a strong and significant predictor for cardiac events during follow-up (p = 0.02). Furthermore, a prior syncope [hazard ratio (HR), 4.05; 95% confidence interval (CI), 1.1 to 15.0; p = 0.03] or an ACA (HR, 11.7; 95% CI, 3.1 to 43.4; p = <0.001) identified children with an increased risk for recurrent cardiac events compared to asymptomatic LQT children. LQTS-index children manifest with a high percentage of severe symptoms. Among presently validated risk factors for LQTS, a QTc interval >500 ms and a history of prior syncope or ACA were strong predictors for recurrent cardiac events.
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PMID:QT interval prolongation and risk for cardiac events in genotyped LQTS-index children. 1910 29