The compound heterozygous mutations of W176X and G589S coexisting in KCNQ1 gene of homologous chromosomes, resulting in more severe phenotype, are the likely pathogenic and genetic risks of LQTS and USD in this Chinese family.
The sodium channel gene SCN5A and potassium channel genes KCNQ1 and KCNH2 have been widely reported to be genetic risk factors for arrhythmia including Brugada syndrome and long QT syndrome (LQTS).
Patients had LQTS type 1 (LQT1), type 2 (LQT2), and type 3 (LQT3) (616 probands and 508 family members), with KCNQ1 (n = 521), KCNH2 (n = 487) and SCN5A (n = 116) genes.
We generated PSMi001-A and PSMi008-A hiPSC lines from two individuals belonging to a South African (SA) founder population in which the malignant KCNQ1-A341V mutation cosegregates with the Long QT Syndrome (LQTS) phenotype.
The potential role of sodium channel blockers in patients with potassium channel-mediated long QT syndrome (ie, LQT1 and LQT2) has not been investigated in detail.
We generated human induced pluripotent stem cells (hiPSCs) from a symptomatic Long QT Syndrome (LQTS) type 1 patient, belonging to a South African (SA) founder population segregating the heterozygous mutation c.1022C > T p.A341V on the KCNQ1 gene.
ML277 provides insights and a tool to investigate the gating mechanism of KCNQ1 channels, and our study reveals a new strategy for treating long QT syndrome by specifically enhancing the AO state of native I<sub>Ks</sub> currents.
Clinical, electrophysiological and genetic characterization of a large pedigree (<i>n</i> = 241 family members) with LQT syndrome caused by a 12-base-pair duplication in exon 8 of the <i>KCNQ1</i> gene duplicating four amino acids in the carboxyterminal KCNQ1 domain (<i>KCNQ1</i>dup12; p.R360_Q361dupQKQR, NM_000218.2, hg19).
Type 1 long-QT syndrome is associated with the genetic variants of KCNQ1 gene that encodes Kv7.1, the α-subunit of the voltage-gated potassium channel QKT subfamily member 1 that channels the slow component of the outwardly rectifying K<sup>+</sup> channel current in cardiac myocytes.
After ATO treatment, the Kcnq1ot1 and Kcnq1 expression levels were down regulated. lncRNA Kcnq1ot1 knockdown prolonged the action potential duration (APD) in vitro and exerted LQTS in vivo.
The study cohort consisted of 67 KCNQ1 mutation carriers and 13 family members who were suspected as having LQTS due to sudden cardiac death or syncope from 36 unrelated families.
[<sup>11</sup>C]mHED-PET was performed in 25 patients with LQTS (LQT1: n=14; LQT2: n=11) and 20 healthy controls and correlated with clinical parameters.
We investigated the genetic causes in patients with prolonged QTc intervals who were negative for pathogenic variants in three major LQTS-related genes (KCNQ1, KCNH2, and SCN5A).
The study included 59 LQT1 and 72 LQT2 patients from the Rochester-based LQTS Registry with corrected QT (QT<sub>c</sub>) prolongation and a history of AD therapy.
It has been suggested that ∼10%-20% of rare LQTS case-derived variants in the literature may have been published erroneously as LQT1-causative mutations and may be "false positives."
Catecholaminergic polymorphic ventricular tachycardia (CPVT) has been often misdiagnosed as long QT syndrome (LQTS) type 1 (LQT1), which phenotypically mimics CPVT but has a relatively better prognosis.