Key result
A heterozygous point mutation (R176W) in the KCNH2 gene, typically associated with a mild phenotype, manifested malignantly with prolonged syncope and torsade de pointes in a 12-year-old girl.
Case Report (n=1)
The KCNH2 R176W mutation, previously thought to be benign or mild, can present with malignant manifestations such as torsade de pointes and cardiac arrest.
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May indicate severe arrhythmia risk with KCNH2 R176W; hypothesis-generating and requires validation in larger cohorts.
A 12-year-old girl presented with a first prolonged syncope. She was successfully resuscitated by external defibrillation after recording torsade de pointes tachycardia. Repeated electrocardiograms and a 12-channel Holter monitoring showed an intermittent prolongation of the QT interval. Genetic analysis identified a heterozygous point mutation in the KCNH2 gene, which is thought to be associated with a rather mild clinical phenotype of the long QT syndrome.
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Donner et al. (2011) conducted a case report in Long QT syndrome (n=1). KCNH2 gene mutation (R176W) was evaluated on Clinical manifestation (prolonged syncope, torsade de pointes, QT prolongation). A heterozygous point mutation (R176W) in the KCNH2 gene, typically associated with a mild phenotype, manifested malignantly with prolonged syncope and torsade de pointes in a 12-year-old girl.
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