TY - JOUR
T1 - Genotype and clinical characteristics of congenital long QT syndrome in Thailand
AU - Saprungruang, Ankavipar
AU - Khongphatthanayothin, Apichai
AU - Mauleekoonphairoj, John
AU - Wandee, Pharawee
AU - Kanjanauthai, Supaluck
AU - Bhuiyan, Zahurul A.
AU - Wilde, Arthur A. M.
AU - Poovorawan, Yong
PY - 2018
Y1 - 2018
N2 - Background: Congenital long QT syndrome (LQTS) is an inheritable arrhythmic disorder which is linked to at least 17 genes. The clinical characteristics and genetic mutations may be variable among different population groups and they have not yet been studied in Thai population. Methods: Clinical characteristics were retrospectively reviewed from children and young adults with congenital long QT syndrome whose blood samples were sent for genotyping during 1998–2017. Sangers sequencing was used to sequentially identify KCNQ1 or KCNH2 genetic variants. Whole exome sequencing (WES) was used to identify variants in all other known LQTS genes. Results: Of the 20 subjects (17 families), 45% were male, mean QTc was 550.3 ± 68.8 msec (range 470–731 msec) and total Schwartz's score was 5.6 ± 1.2 points (range 3–8 points). Fifty percent of patients had events at rest, 30% had symptoms after adrenergic mediated events, and 20% were asymptomatic. We discovered pathogenic and likely pathogenic genetic variants in KCNQ1, KCNH2, and SCN5A in 6 (35%), 4 (24%), and 2 (12%) families, respectively. One additional patient had variance of unknown significance (VUS) in KCNH2 and another one in ANK2. No pathogenic genetic variant was found in 3 patients (18%). Most patients received beta-blocker and 9 (45%) had ICD implanted. LQT1 patients were either asymptomatic or had stress-induced arrhythmia. Most of the LQT2 and LQT3 patients developed symptoms at rest or during sleep. Conclusions: Our patients with LQTS were mostly symptomatic at presentation. The genetic mutations were predominantly in LQT1, LQT2, and LQT3 genes.
AB - Background: Congenital long QT syndrome (LQTS) is an inheritable arrhythmic disorder which is linked to at least 17 genes. The clinical characteristics and genetic mutations may be variable among different population groups and they have not yet been studied in Thai population. Methods: Clinical characteristics were retrospectively reviewed from children and young adults with congenital long QT syndrome whose blood samples were sent for genotyping during 1998–2017. Sangers sequencing was used to sequentially identify KCNQ1 or KCNH2 genetic variants. Whole exome sequencing (WES) was used to identify variants in all other known LQTS genes. Results: Of the 20 subjects (17 families), 45% were male, mean QTc was 550.3 ± 68.8 msec (range 470–731 msec) and total Schwartz's score was 5.6 ± 1.2 points (range 3–8 points). Fifty percent of patients had events at rest, 30% had symptoms after adrenergic mediated events, and 20% were asymptomatic. We discovered pathogenic and likely pathogenic genetic variants in KCNQ1, KCNH2, and SCN5A in 6 (35%), 4 (24%), and 2 (12%) families, respectively. One additional patient had variance of unknown significance (VUS) in KCNH2 and another one in ANK2. No pathogenic genetic variant was found in 3 patients (18%). Most patients received beta-blocker and 9 (45%) had ICD implanted. LQT1 patients were either asymptomatic or had stress-induced arrhythmia. Most of the LQT2 and LQT3 patients developed symptoms at rest or during sleep. Conclusions: Our patients with LQTS were mostly symptomatic at presentation. The genetic mutations were predominantly in LQT1, LQT2, and LQT3 genes.
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85050293492&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/30036649
U2 - https://doi.org/10.1016/j.ipej.2018.07.007
DO - https://doi.org/10.1016/j.ipej.2018.07.007
M3 - Article
C2 - 30036649
SN - 0972-6292
VL - 18
SP - 165
EP - 171
JO - Indian pacing and electrophysiology journal
JF - Indian pacing and electrophysiology journal
IS - 5
ER -