Identifying genomic variant associated with long QT syndrome type 2 in an ecuadorian mestizo individual: a case report

<jats:sec><jats:title>Introduction</jats:title><jats:p>Long QT syndrome (LQTS) is an autosomal dominant inherited cardiac condition characterized by a QT interval prolongation and risk of sudden death. There are 17 subtypes of this syndrome associated with genetic variants in 11 genes. The second most common is type 2, caused by a mutation in the <jats:italic>KCNH2</jats:italic> gene, which is part of the potassium channel and influences the final repolarization of the ventricular action potential. This case report presents an Ecuadorian teen with congenital Long QT Syndrome type 2 (OMIM ID: 613688), from a family without cardiac diseases or sudden cardiac death backgrounds.</jats:p></jats:sec><jats:sec><jats:title>Case presentation</jats:title><jats:p>A 14-year-old girl with syncope, normal echocardiogram, and an irregular electrocardiogram was diagnosed with LQTS. Moreover, by performing Next-Generation Sequencing, a pathogenic variant in the <jats:italic>KCNH2</jats:italic> gene p.(Ala614Val) (ClinVar ID: VCV000029777.14) associated with LQTS type 2, and two variants of uncertain significance in the <jats:italic>AKAP9</jats:italic> p.(Arg1654GlyfsTer23) (rs779447911), and <jats:italic>TTN</jats:italic> p. (Arg34653Cys) (ClinVar ID: VCV001475968.4) genes were identified. Furthermore, ancestry analysis showed a mainly Native American proportion.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Based on the genomic results, the patient was identified to have a high-risk profile, and an implantable cardioverter defibrillator was selected as the best treatment option, highlighting the importance of including both the clinical and genomics aspects for an integral diagnosis.</jats:p></jats:sec>