Only 5 SCN5A mutations have been associated with LQTS, and more work is needed to improve correlations between SCN5A genotypes and associated clinical syndromes.
Mutations in the KVLQT1 gene, encoding a potassium-channel subunit of importance for the depolarisation of cardiac myocytes, is believed to be associated with 50% of all LQTS cases.
Genetic studies have identified four forms of congenital long QT syndrome (LQTS) caused by mutations in ion channel genes located on chromosomes 3 (LQT3), 7 (LQT2), 11 (LQT1), and 21 (LQT5).
Mutations in the human ether-a-go-go-related gene (HERG), which encodes the rapidly activating component of the delayed rectifier current (IKr), cause chromosome 7-linked LQTS (LQT2).
Genetic studies have identified four forms of congenital long QT syndrome (LQTS) caused by mutations in ion channel genes located on chromosomes 3 (LQT3), 7 (LQT2), 11 (LQT1), and 21 (LQT5).
Genetic studies have identified four forms of congenital long QT syndrome (LQTS) caused by mutations in ion channel genes located on chromosomes 3 (LQT3), 7 (LQT2), 11 (LQT1), and 21 (LQT5).
These data extend the range of known KCNQ1 mutations associated with both recessive and dominant forms of congenital long QT syndrome, and demonstrate that the R518X allele may be associated with or without congenital deafness.
Congenital long-QT syndrome (LQTS) is caused by mutations of genes encoding the slow component of the delayed rectifier current (LQT1, LQT5), the rapid component of the delayed rectifier current (LQT2, LQT6), or the Na(+) current (LQT3), resulting in ST-T-wave abnormalities on the ECG.
Survey of the coding region of the HERG gene in long QT syndrome reveals six novel mutations and an amino acid polymorphism with possible phenotypic effects.
The novel KCNQ1 mutation R259C is the molecular basis for I(Ks) dysfunction underlying an apparently sporadic case of hypokalemia-induced LQTS, consistent with a mild mutation likely to disclose the clinical manifestation of LQTS in a context of severe hypokalemia.
Congenital long-QT syndrome (LQTS) is caused by mutations of genes encoding the slow component of the delayed rectifier current (LQT1, LQT5), the rapid component of the delayed rectifier current (LQT2, LQT6), or the Na(+) current (LQT3), resulting in ST-T-wave abnormalities on the ECG.
The congenital long-QT syndrome (LQT3) and the Brugada syndrome are distinct, life-threatening rhythm disorders linked to autosomal dominant mutations in SCN5A, the gene encoding the human cardiac Na(+) channel.
Congenital long-QT syndrome (LQTS) is caused by mutations of genes encoding the slow component of the delayed rectifier current (LQT1, LQT5), the rapid component of the delayed rectifier current (LQT2, LQT6), or the Na(+) current (LQT3), resulting in ST-T-wave abnormalities on the ECG.
D1790G, a mutation of SCN5A, the gene that encodes the human Na(+) channel alpha-subunit, is linked to 1 form of the congenital long-QT syndrome (LQT-3).
Mutations in SCN5A, encoding the cardiac sodium (Na) channel, are linked to a form of the congenital long-QT syndrome (LQT3) that provokes lethal ventricular arrhythmias.