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Long QT syndrome 5(LQT5)

MedGen UID:
358092
Concept ID:
C1867904
Disease or Syndrome
Synonyms: LQT5
Modes of inheritance:
Heterogeneous
MedGen UID:
67020
Concept ID:
C0242960
Organism Attribute
Source: HPO
The presence of apparently similar characters for which the genetic evidence indicates that different genes or different genetic mechanisms are involved in different pedigrees. In clinical settings genetic heterogeneity refers to the presence of a variety of genetic defects which cause the same disease, often due to mutations at different loci on the same gene, a finding common to many human diseases including ALZHEIMER DISEASE; CYSTIC FIBROSIS; LIPOPROTEIN LIPASE DEFICIENCY, FAMILIAL; and POLYCYSTIC KIDNEY DISEASES. (Rieger, et al., Glossary of Genetics: Classical and Molecular, 5th ed; Segen, Dictionary of Modern Medicine, 1992)
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
Autosomal dominant inheritance (HPO, OMIM, Orphanet)
 
Gene (location): KCNE1 (21q22.12)
OMIM®: 613695

Definition

Long QT syndrome (LQTS) is a cardiac electrophysiologic disorder, characterized by QT prolongation and T-wave abnormalities on the ECG and the ventricular tachycardia torsade de pointes (TdP). TdP is usually self-terminating, thus causing a syncopal event, the most common symptom in individuals with LQTS. Syncope typically occurs during exercise and high emotions, less frequently at rest or during sleep, and usually without warning. In some instances, TdP degenerates to ventricular fibrillation and causes aborted cardiac arrest (if the individual is defibrillated) or sudden death. Approximately 50% of individuals with a pathogenic variant in one of the genes associated with LQTS have symptoms, usually one to a few syncopal spells. While cardiac events may occur from infancy through middle age, they are most common from the pre-teen years through the 20s. Some types of LQTS are associated with a phenotype extending beyond cardiac arrhythmia. In addition to the prolonged QT interval, associations include muscle weakness and facial dysmorphism in Andersen-Tawil syndrome (LQTS type 7), hand/foot, facial, and neurodevelopmental features in Timothy syndrome (LQTS type 8) and profound sensorineural hearing loss in Jervell and Lange-Nielson syndrome. [from GTR]

Additional descriptions

From GeneReviews
Long QT syndrome (LQTS) is a cardiac electrophysiologic disorder, characterized by QT prolongation and T-wave abnormalities on the ECG and the ventricular tachycardia torsade de pointes (TdP). TdP is usually self-terminating, thus causing a syncopal event, the most common symptom in individuals with LQTS. Syncope typically occurs during exercise and high emotions, less frequently at rest or during sleep, and usually without warning. In some instances, TdP degenerates to ventricular fibrillation and causes aborted cardiac arrest (if the individual is defibrillated) or sudden death. Approximately 50% of individuals with a pathogenic variant in one of the genes associated with LQTS have symptoms, usually one to a few syncopal spells. While cardiac events may occur from infancy through middle age, they are most common from the pre-teen years through the 20s. Some types of LQTS are associated with a phenotype extending beyond cardiac arrhythmia. In addition to the prolonged QT interval, associations include muscle weakness and facial dysmorphism in Andersen-Tawil syndrome (LQTS type 7), hand/foot, facial, and neurodevelopmental features in Timothy syndrome (LQTS type 8) and profound sensorineural hearing loss in Jervell and Lange-Nielson syndrome.  https://www.ncbi.nlm.nih.gov/books/NBK1129
From OMIM
Congenital long QT syndrome is electrocardiographically characterized by a prolonged QT interval and polymorphic ventricular arrhythmias (torsade de pointes). These cardiac arrhythmias may result in recurrent syncope, seizure, or sudden death (Jongbloed et al., 1999). For a discussion of genetic heterogeneity of long QT syndrome, see LQT1 (192500).  http://www.omim.org/entry/613695

Clinical features

Syncope
MedGen UID:
21443
Concept ID:
C0039070
Sign or Symptom
A spontaneous loss of consciousness caused by insufficient blood supply to the brain.
Torsades de pointes
MedGen UID:
21214
Concept ID:
C0040479
Disease or Syndrome
A malignant form of polymorphic ventricular tachycardia that is characterized by HEART RATE between 200 and 250 beats per minute, and QRS complexes with changing amplitude and twisting of the points. The term also describes the syndrome of tachycardia with prolonged ventricular repolarization, long QT intervals exceeding 500 milliseconds or BRADYCARDIA. Torsades de pointes may be self-limited or may progress to VENTRICULAR FIBRILLATION.
Ventricular fibrillation
MedGen UID:
21844
Concept ID:
C0042510
Disease or Syndrome
A disorder characterized by an electrocardiographic finding of a rapid grossly irregular ventricular rhythm with marked variability in QRS cycle length, morphology, and amplitude. The rate is typically greater than 300 bpm. (CDISC)
Sudden cardiac death
MedGen UID:
38841
Concept ID:
C0085298
Pathologic Function
An unexpected natural death from a cardiac cause within a short time period from the onset of symptoms.(NICHD)
Prolonged QT interval
MedGen UID:
57494
Concept ID:
C0151878
Finding
An electrocardiographic finding in which the QT interval not corrected for heart rate is prolonged. Thresholds for different age, gender, and patient populations exist. (CDISC)

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  

Recent clinical studies

Etiology

Major P, Baczkó I, Hiripi L, Odening KE, Juhász V, Kohajda Z, Horváth A, Seprényi G, Kovács M, Virág L, Jost N, Prorok J, Ördög B, Doleschall Z, Nattel S, Varró A, Bősze Z
Br J Pharmacol 2016 Jun;173(12):2046-61. Epub 2016 May 19 doi: 10.1111/bph.13500. PMID: 27076034Free PMC Article

Diagnosis

Snipelisky D, Roberts M, Blackshear J
JAMA Intern Med 2014 Nov;174(11):1831-3. doi: 10.1001/jamainternmed.2014.4047. PMID: 25178485

Therapy

Snipelisky D, Roberts M, Blackshear J
JAMA Intern Med 2014 Nov;174(11):1831-3. doi: 10.1001/jamainternmed.2014.4047. PMID: 25178485

Prognosis

Major P, Baczkó I, Hiripi L, Odening KE, Juhász V, Kohajda Z, Horváth A, Seprényi G, Kovács M, Virág L, Jost N, Prorok J, Ördög B, Doleschall Z, Nattel S, Varró A, Bősze Z
Br J Pharmacol 2016 Jun;173(12):2046-61. Epub 2016 May 19 doi: 10.1111/bph.13500. PMID: 27076034Free PMC Article

Clinical prediction guides

Major P, Baczkó I, Hiripi L, Odening KE, Juhász V, Kohajda Z, Horváth A, Seprényi G, Kovács M, Virág L, Jost N, Prorok J, Ördög B, Doleschall Z, Nattel S, Varró A, Bősze Z
Br J Pharmacol 2016 Jun;173(12):2046-61. Epub 2016 May 19 doi: 10.1111/bph.13500. PMID: 27076034Free PMC Article

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