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Genetically Determined Ventricular Arrhythmias
Published in Andrea Natale, Oussama M. Wazni, Kalyanam Shivkumar, Francis E. Marchlinski, Handbook of Cardiac Electrophysiology, 2020
Houman Khakpour, Jason S. Bradfield
To date, 13 genes have been linked to congenital LQTS encoding for potassium, sodium, and calcium channel-related proteins, as well as membrane adaptor proteins.2,3 However, the first 3 genes discovered in 1995, encompassing the patients with LQT1, LQT2, and LQT3 genotypes with mutations involving KCNQ1, KCNH2, and SCN5A make up over 92% of patients with genetically confirmed LQTS.3–6 Notably, up to 20% of patients with LQTS remain genetically undiagnosed after comprehensive genetic testing.7 The majority of LQTS has an autosomal dominant inheritance (Romano–Ward syndrome). The autosomal recessive form (Jervell and Lange-Nielsen syndrome) is rare, more virulent, and associated with deafness. Other rare phenotypes, Anderson–Tawil syndrome and Timothy syndrome, have been classified as LQT7 and LQT8 and are associated with QT prolongation in addition to other distinct clinical manifestations (Table 8.1).7,8
The QT interval
Published in Andrew R Houghton, Making Sense of the ECG, 2019
The autosomal dominant Romano–Ward syndrome consists of recurrent syncopal attacks and sudden death secondary to ventricular tachycardia, torsades de pointes and ventricular fibrillation. The arrhythmias are often triggered by exercise or stress.
Cardiovascular medicine
Published in Shibley Rahman, Avinash Sharma, A Complete MRCP(UK) Parts 1 and 2 Written Examination Revision Guide, 2018
Shibley Rahman, Avinash Sharma
Romano-Ward syndrome is purely a cardiac electrophysiological disorder, characterised by QT prolongation and T-wave abnormalities on the ECG. It is in fact the most common form of inherited long QT syndrome, affecting an estimated 1 in 7000 people worldwide. Mutations in the KCNE1, KCNE2, KCNH2, KCNQ1, and SCN5A genes cause Romano-Ward syndrome.
Precision medicine in cardiac electrophysiology: where we are and where we need to go
Published in Expert Review of Precision Medicine and Drug Development, 2020
Ashish Correa, Syed Waqas Haider, Wilbert S. Aronow
Congenital LQTS is an inherited arrhythmia syndrome characterized by a prolonged QT interval on the surface electrocardiogram (EKG) resulting from abnormal cardiac repolarization that puts an individual at an increased risk for a particular type of polymorphic ventricular tachycardia known as torsades des pointes [20,21]. LQTS are divided into 13 subtypes based on 13 genotypes that have been identified. Each genotype is due to a mutation of a discrete gene. Phenotypically, the disease may present as a cardiac arrhythmia syndrome alone or one associated with other conditions. When occurring without any other associated conditions, it is known as Romano-Ward Syndrome – an LQTS that can be caused by mutations of any the 13 identified genes and with autosomal dominant inheritance [20,22,23]. Other rarer phenotypes of LQTS include Jervell and Lange-Nielsen Syndrome, Andersen-Tawil Syndrome, and Timothy Syndrome. Jervell and Lange-Nielsen Syndrome (JLNS) is an extremely severe and rare autosomal recessive disorder characterized by marked QT prolongation with high rates of SCD as well as sensorineural deafness [24]. Andersen-Tawil Syndrome, also known as hypokalemic periodic paralysis or long QT syndrome 7 (LQT7) is an autosomal dominant disorder characterized by a triad of a prolonged QT interval with ventricular arrhythmias, potassium-sensitive periodic paralysis and various dysmorphic features [25,26]. Timothy Syndrome or LQT8 is an extremely rare autosomal recessive arrhythmia syndrome characterized by various arrhythmias, QT prolongation, and developmental disorders [27].
Mutation Screening of KCNQ1 and KCNE1 Genes in Iranian Patients With Jervell and Lange-Nielsen Syndrome
Published in Fetal and Pediatric Pathology, 2019
Samaneh Vojdani, Susan Amirsalari, Saman Milanizadeh, Fatemeh Molaei, Mohammad Ajalloueyane, Arezoo Khosravi, Leila Hamzehzadeh, Mohammad Mehdi Ghasemi, Mohammad Reza Talee, Mohammad Reza Abbaszadegan
Long QT syndrome (LQTS) is classified into two disorders—Romano–Ward syndrome (RWS) and Jervell and Lange-Nielsen syndrome (JLNS) [1–3]. JLNS is an autosomal recessive variant of LQTS with a prevalence of 1.6 to 6 per 1 million people worldwide but is more common in Denmark, Sweden, and Norway, where it affects at least 1 in 200,000 people.