Long QT Syndrome 2

Alternative Names

LQT2
Long QT Syndrome 2, Acquired, Susceptibility to
Long QT Syndrome 1/2, Digenic
LQT1/2, Digenic
Long QT Syndrome 2/3, Digenic
LQT2/3, Digenic
Long QT Syndrome 2/5, Digenic
LQT2/5, Digenic
Long QT Syndrome 2/9, Digenic
LQT2/9, Digenic

Associated Genes

Potassium Channel, Voltage-Gated, Subfamily H, Member 2

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WHO-ICD-10 version:2010

Diseases of the circulatory system

Other forms of heart disease

OMIM Number

613688

Mode of Inheritance

Autosomal dominant

Gene Map Locus

7q36.1,12q12

Description

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. It can be caused by mutations in several cardiac ion channel genes. There are eight types of LQT syndrome based on the gene in which causative mutations occur. The most prevalent forms are LQT1, LQT2, and LQT3. Half of individuals with LQT2 remain asymptomatic until the age of 16. Symptoms are triggered by a variety of causes including emotions, auditory experience, and exercise. Furthermore, some cases may occur during rest and sleep.

The diagnosis of LQT2 is based on electrocardiogram (ECG) abnormalities; notched T waves are most commonly seen in this type. Patients with LQT2 have symptom relief from beta-blocker therapy. Symptoms can also be improved in patients who maintain their potassium levels and modify their lifestyles. Treatment with potassium may be recommended.

Epidemiology in the Arab World

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Subject ID	Country	Sex	Family History	Parental Consanguinity	HPO Terms	Variant	Zygosity	Mode of Inheritance	Reference	Remarks
613688.1.1	Lebanon	Male	Yes		Sudden cardiac death; Death in early ad... Sudden cardiac death; Death in early adulthood	NM_000238.3:c.1837A>G	Heterozygous	Autosomal, Dominant	Poulsen et al. 2015
613688.1.2	Lebanon	Female	Yes		Prolonged QTc interval Prolonged QTc interval	NM_000238.3:c.1837A>G	Heterozygous	Autosomal, Dominant	Poulsen et al. 2015	Sibling of 613688.1....
613688.1.3	Lebanon	Male	Yes		Syncope; Prolonged QTc interval Syncope; Prolonged QTc interval	NM_000238.3:c.1837A>G	Heterozygous	Autosomal, Dominant	Poulsen et al. 2015	Father of 613688.1.1
613688.2.1	Saudi Arabia	Female	No	No	Bilateral tonic-clonic seizure; Prolonge... Bilateral tonic-clonic seizure; Prolonged QT interval	NM_000238.4:c.2362G>A	Homozygous	Autosomal, Recessive	Bhuiyan et al. 2009
613688.3.1	Saudi Arabia	Female	No	No	Bilateral tonic-clonic seizure; Prolonge... Bilateral tonic-clonic seizure; Prolonged QT interval	NM_000238.4:c.1609C>T, NM_000238.4:c.2342dup	Heterozygous	Autosomal, Recessive	Bhuiyan et al. 2009
613688.4.1	Saudi Arabia	Male	Yes	Yes	Polymorphic ventricular tachycardia; Pro... Polymorphic ventricular tachycardia; Prolonged QT interval; Arrhythmia	NM_000238.4:c.3208C>T	Homozygous	Autosomal, Recessive	Bhuiyan et al. 2009	Proband. HIs mother ...
613688.4.2	Saudi Arabia	Female	Yes	Yes	Arrhythmia; Stillbirth Arrhythmia; Stillbirth	NM_000238.4:c.3208C>T	Homozygous	Autosomal, Recessive	Bhuiyan et al. 2009	Sister of 613688.4.1
613688.5.1	Saudi Arabia	Male	No	No	Bradycardia; Cardiac arrest; Prolonged Q... Bradycardia; Cardiac arrest; Prolonged QT interval	NM_000238.4:c.3208C>T	Homozygous	Autosomal, Recessive	Bhuiyan et al. 2009