Long QT syndrome comprising a set of type congenital cardiac disorders associated with mutations in genes, that encodes ion channels, under an autosomal dominant inheritance pattern.
The long QT syndrome is characterized by a number of associated features such as polymorphic ventricular arrhythmias (able to cause seizures, syncope or sudden death) QT prolongation and T wave abnormalities
In 46% of cases, the disease is caused by mutations in the gene encoding a KCNQ1 potassium channel. However, there are also a number of associated alterations in different genes, which would lead prolonging the action potential duration. Mutations have been reported in: KCNE1, KCNE2, KCNH2, KCNQ1, CACNA1c, CAV3, SCN4B, SCN5A.
Symptoms and signs of disease are clear. However, in some instances will require a more specific approach for patients with atypical syndrome. The molecular test is included in the diagnostic process.
It is considered a prevalence of 1 per 3000-7000 individuals.
Treatment of the disease should be initiated with beta-blockers, and if the patient has episodes of syncope despite higher dosing of beta-blockers, It is advisable to make a left cardiac sympathetic denervation in addition to treatment with implantable cardioverter-defibrillator.
Although the prognosis is favorable, there are some serious variants disease such as Timothy syndrome (# 601005) and Jervell and Lange-Nielsen syndrome (# 220400), among others. Bioarray has a NGS panel for the sequencing of the genes linked to the onset of the disease.
You can find more about the different types of long QT syndrome in their sections.