UNPREDICTABLE IDENTIFICATION OF A TITIN MUTATION IN A YOUNG PATIENT PRESENTING WITH INFLAMMATORY CARDIOMYOPATHY

Abstract

Abstract Case Presentation A 23 years old patient, affected by type 1 diabetes, presented with fever, dyspnea and bilateral peripheral edemas. In the last week he received antibiotic treatment for a persistent dry cough and sore throat, and became symptomatic for exertional dyspnea from three days. His mother died at the age of 40 for sudden cardiac death. Blood pressure and oxygen saturation were normal: the ECG showed sinus tachycardia with symmetric negative T waves in all precordial leads. High sensitivity troponin T was 0.01 mcg/L (normal value < 0.014 mcg/L). All remaining blood tests were normal, except for CRP that was slightly elevated. His echocardiogram revealed left ventricular (LV) remodelling and dilation, severely reduced LV ejection fraction (LVEF 20%) with global hypokinesia, more pronounced at the level of the anterior wall, interventricular septum and apex and a dilated right ventricle (RV) with reduced systolic function. Cardiac magnetic resonance (CMR) confirmed severe biventricular disfunction (LVEF 19%; RVEF 23%) and showed a small area of subepicardial inferior junctional late gadolinium enhancement (LGE). The patient underwent an endomyocardial biopsy that showed a lymphocytic virus–negative myocarditis. Given his known type 1 diabetes, steroid treatment was not considered and anakinra was started. The patient was discharged after two weeks with a slight amelioration of the LV function (LVEF 27%), on optimal heart failure therapy and anakinra. At six months he was in NYHA class II and CMR showed slight reduction in LV dimensions and improvement of the LV and RV function (LVEF 39%; RVEF 45%), with no changes in the LGE pattern. A genetic test was performed and revealed two titin gene mutations, both categorized as likely pathogenic (TTN c.[11831T>A]; c.[72510_72517delGACAAATG]), responsible for a genetic form of dilated cardiomyopathy. Conclusion The present case suggests that in young patients presenting with clinical or histological diagnosis of myocarditis, genetic testing for cardiomyopathies should be considered especially in presence of a positive family history for sudden death or an incomplete recovery of the LV function at follow–up. Identification of a gene mutation in these patients allows a more tailored risk stratification of the index case and a proper management of the entire family.