Co-occurrence of Marfan syndrome and long QT syndrome in an adolescent and her family

This case report describes the management of a 15-year-old girl with the rare co-occurrence of Marfan syndrome and long QT syndrome, highlighting both clinical and genetic aspects.The patient presented with seizure-like activity and altered mental status, and initial tests revealed significant QT prolongation and ventricular arrhythmias.She was treated with nadolol and mexiletine, resulting in substantial improvement without the need for defibrillator implantation.Genetic testing identified a pathogenic variant in KCNH2, linked to long QT syndrome type 2, and a likely pathogenic variant in FBN1, associated with Marfan syndrome.Family screening confirmed the inheritance of these mutations from her father.This case emphasizes the necessity of comprehensive genetic evaluation and personalized management strategies to prevent sudden cardiac death in patients with a dual diagnosis of genetic disorders.