We studied 169 LQTS genotype-positive patients < 50 years of age who performed an ExStrT with the same protocol, on and off β-blockers including 47 South African LQT1 patients all harboring the KCNQ1-A341V mutation and 122 Italian LQTS patients with impaired (I(Ks)-, 66 LQT1) or normal (I(Ks)+, 50 LQT2 and 6 LQT3) I(Ks) current.
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.
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.
This study tested the hypothesis that vagal and sympathetic control, as assessed by spectral analysis of spontaneous beat-to-beat variability of RR and QT intervals from standard 24-h electrocardiogram Holter recordings, could modulate the severity of LQTS type 1 (LQT1) in 46 members of a South-African LQT1 founder population carrying the clinically severe KCNQ1 A341V mutation.
The common long-QT syndrome mutation KCNQ1/A341V causes unusually severe clinical manifestations in patients with different ethnic backgrounds: toward a mutation-specific risk stratification.
We studied the effect of D85N on age-, sex-, and heart rate-adjusted QT-interval duration by linear regression in LQTS patients carrying the Finnish founder mutations KCNQ1 G589D (n = 492), KCNQ1 IVS7-2A>G (n = 66), KCNH2 L552S (n = 73), and KCNH2 R176W (n = 88).
A total of six compound heterozygotes were identified who had the HERG R176W mutation in combination with a previously reported LQTS mutation (KCNQ1 G589D or IVS7-2A>G).
One of the most common and potentially life-threatening electrolyte disturbances is hypokalemia, characterized by low concentrations of K<sup>+</sup> Using a multielectrode array platform and current clamp technique, we investigated the effect of low extracellular K<sup>+</sup> concentration ([K<sup>+</sup>]<sub>Ex</sub>) on the electrophysiological properties of hiPSC-derived cardiomyocytes (CMs) generated from a healthy control subject (WT) and from two symptomatic patients with type 1 of LQTS carrying G589D (LQT1A) or IVS7-2A>G mutation (LQT1B) in <i>KCNQ1</i> The baseline prolongations of field potential durations (FPDs) and action potential durations (APDs) were longer in LQT1-CMs than in WT-CMs.
A KCNQ1 V205M missense mutation causes a high rate of long QT syndrome in a First Nations community of northern British Columbia: a community-based approach to understanding the impact.
We examined the role of a novel synonymous <i>KCNQ1</i> p.L353L variant on the splicing of exon 8 and on heart rate corrected QT interval (QTc) in a population known to have a pathogenic LQTS type 1 (LQTS1) causative mutation, p.V205M, in <i>KCNQ1</i>-encoded Kv7.1.
The R518X/KCNQ1 mutation is a common cause of autosomal recessive (Jervell and Lange Nielsen Syndrome- JLNS) and autosomal dominant long QT syndrome (LQTS) worldwide.
The R518X allele was previously associated with recessive long QT syndrome without deafness, but was present in a congenitally deaf proband in our study.
The second mutation, V254M in KCNQ1, co-segregated with higher QT intervals and symptoms in other family members, and was previously reported in another LQTS family.
G314S, co-expressed with WT KCNQ1 and KCNE1, suppressed I(ks) currents in a dominant-negative manner, which is consistent with long QT syndrome in the members of the Chinese family carrying G314S KCNQ1 mutation.
In the present study, we show that PIP2 affinity is reduced in three KCNQ1 mutant channels (R243H, R539W, and R555C) associated with the long QT syndrome.
The inconsistent association of the KCNQ1 S277L mutation with the clinical presentation suggests that additional genetic, epigenetic, or environmental factors play a role in defining the individual clinical LQTS phenotype.
Ion channel mechanisms related to sudden cardiac death in phenotype-negative long-QT syndrome genotype-phenotype correlations of the KCNQ1(S349W) mutation.