Long QT syndrome 2

General Information (adopted from Orphanet):

Synonyms, Signs: LQT2, LONG QT SYNDROME 2/3, DIGENIC, INCLUDED
LQT2 LONG QT SYNDROME 2, ACQUIRED, SUSCEPTIBILITY TO, INCLUDED
LQT1/2, DIGENIC, INCLUDED
LQT2/9, DIGENIC, INCLUDED
LONG QT SYNDROME 2/9, DIGENIC, INCLUDED
LONG QT SYNDROME 2/5, DIGENIC, INCLUDED
LQT2/3, DIGENIC, INCLUDED
LONG QT SYNDROME 1/2, DIGENIC, INCLUDED
LQT2/5, DIGENIC, INCLUDED
LQT2
Number of Symptoms 13
OrphanetNr:
OMIM Id: 613688
ICD-10:
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal dominant
20301308 [IBIS]
Age of onset:

Disease classification (adopted from Orphanet):

Parent Diseases: Romano-Ward syndrome
 -Rare cardiac disease
 -Rare genetic disease

Comment:

LQT2 is a sub-type of Romano-Ward syndrome, a variant of familial long QT syndrome. It is characterized by mutations in the KCNH2 gene. Epileptic events are more common in LQT2 subtype. A specific trigger for arrhythmic events in LQT2 is auditory stimulation but also emotional stress, as well as the postpartum period. Typically, a biphasic T wave is observed (PMID:25274057). Mutations in the ALG10 gene confers reduced susceptibility to acquired long QT syndrome-2.

Symptom Information: Sort by abundance 

1
 (HPO:0005135) EKG: T-wave abnormalities Very frequent [IBIS] 25274057 IBIS 19 / 7739
2
 (HPO:0012266) T-wave alternans Frequent [IBIS] 25274057 IBIS 8 / 7739
3
 (HPO:0001657) Prolonged QT interval Very frequent [IBIS] 25274057 IBIS 33 / 7739
4
 (HPO:0001692) Primary atrial arrhythmia Frequent [IBIS] 33% (n=21) 19017345 IBIS 16 / 7739
5
 (HPO:0004756) Ventricular tachycardia 25274057 IBIS 55 / 7739
6
 (HPO:0004308) Ventricular arrhythmia 1884444 IBIS 46 / 7739
7
 (HPO:0001664) Torsade de pointes Frequent [IBIS] 25274057 IBIS 15 / 7739
8
 (HPO:0001663) Ventricular fibrillation 25274057 IBIS 35 / 7739
9
 (HPO:0001695) Cardiac arrest 25274057 IBIS 87 / 7739
10
 (HPO:0001645) Sudden cardiac death 25274057 IBIS 84 / 7739
11
 (HPO:0001279) Syncope Frequent [IBIS] 25274057 IBIS 94 / 7739
12
 (HPO:0001250) Seizures 25274057 IBIS 1245 / 7739
13
 (HPO:0011097) Epileptic spasms Frequent [IBIS] 25274057 IBIS 45 / 7739

Associated genes:

KCNH2;

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference
KCNH2 rs121912504 pathogenic RCV000015501.21
KCNH2 rs121912505 pathogenic RCV000015502.25
KCNH2 rs121912506 pathogenic RCV000015505.25
KCNH2 rs121912507 pathogenic RCV000015508.25
KCNH2 rs121912508 pathogenic RCV000015509.26
KCNH2 rs121912509 pathogenic RCV000015512.25
KCNH2 rs121912510 pathogenic RCV000015513.21
KCNH2 rs121912511 pathogenic RCV000015515.25
KCNH2 rs121912512 pathogenic RCV000015516.25
KCNH2 rs121912513 pathogenic RCV000015522.25
KCNH2 rs121912516 pathogenic RCV000015528.25
KCNH2 rs189014161 pathogenic RCV000157266.1
KCNH2 rs199472884 pathogenic RCV000157261.1
KCNH2 rs199472942 pathogenic RCV000022644.25
KCNH2 rs199472944 pathogenic RCV000022643.25
KCNH2 rs199473428 pathogenic RCV000157264.1
KCNH2 rs28928904 pathogenic RCV000015504.25
KCNH2 rs587777907 pathogenic RCV000144957.2
KCNH2 rs730880116 pathogenic RCV000157258.1
KCNH2 rs730880374 likely pathogenic RCV000157260.1
KCNH2 rs77331749 pathogenic RCV000015526.25
KCNH2 rs9333649 pathogenic RCV000015510.22

Additional Information:

Description: (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 syncopes, seizure, or sudden death (Jongbloed et al., 1999).
Genotype-Phenotype Correlations OMIM In a large collaborative study, Zareba et al. (1998) determined the influence of genotype on phenotype of the long QT syndrome; 112 persons had mutations at the LQT1 locus, 72 had mutations at the LQT2 locus, and 62 ...
Molecular genetics OMIM Curran et al. (1995) performed single-strand conformation polymorphism and DNA sequence analyses and detected HERG mutations in 6 LQT families, including 2 intragenic deletions, 1 splice-donor mutation, and 3 missense mutations. In 1 kindred, the mutation arose de ...