2023 Volume 72 Issue 3 Pages 111-122
Congenital long QT syndrome is a disorder in which the QT interval on electrocardiography is prolonged due to an abnormality in the genes encoding ion channels in cardiomyocytes, which sometimes results in fatal arrhythmias. We herein report a case of congenital long QT syndrome type 2（LQT2）with a de novo novel nonsense mutation in the KCNH2.
An asymptomatic 13-year-old female client was admitted to Yamaguchi University Hospital for further examination of QT prolongation that was found in a school physical examination. A catecholamine provocation test showed further prolongation of the QT interval. She has been followed up as an outpatient once a year for six years. In this time, there have been no symptoms. When she was 18 years of age, genetic testing was performed for her and her family. As a heterozygous nonsense mutation of KCNH2 c.1490G>A, p.Trp497Ter was found only in the patient, de novo mutation was confirmed. Furthermore, as the association between the variant and long QT syndrome has not been reported, it seemed to be a novel mutation. Although she has remained asymptomatic thus far, she should be followed up carefully because female patients with LQT2 have an increased risk of cardiac events after puberty.
