OC-39 Cardiac involvement in inherited metabolic diseases

Background and aims Inherited metabolic diseases (IMD) have an increasing prevalence, and can be detected by neonatal screening, at their onset as an acute decompensation or a chronic disease. The heart is a target organ in these disorders and can compromise the patient life if no early treatment is employed. The aim of this study is to describe the cases occurred in a tertiary children hospital and to analyse the heart involvement. Methods Retrospective study of 14 cases diagnosed with cardiomyopathy associated to IMD in a tertiary children’s hospital from January 2010 to January 2017. Results among the 14 cases described, 4 were lysosomal storage disorders (2 Pompe diseases, 1 Hunter disease (HD), 1 mucopolysaccharidosis type IX (Sly syndrome), 7 β-oxidation disorders (3 CPT2 deficiency, 2 carnitine transporter deficiency, 2 VLCAD), 1 glycosylation defect, 1 atypical progeroid syndrome (APS) and 1 glycine encephalopathy. Regarding cardiac involvement, hypertrophic cardiomyopathy was the most frequent one (8 cases), followed by rhythm disorders (1 VLCAD deficiency with paroxysmal supraventricular tachycardia, 3 CPT II deficiency with lethal neonatal form), 1 case of dilated cardiomyopathy and 1 severe pulmonary hypertension with secondary cardiac failure. 11 cases were diagnosed at disease onset and only in 3 cases the cardiac involvement emerged during the course of the disease, having been previously diagnosed with the underlying disease (HD, VLCADD, APS). 6 patients died and 4 developed sequelae from the underlying diseases or the heart involvement. Only 4 remain healthy, with remission of the cardiomyopathy. Treatment was pharmacological for all patients except for the HD one, who required surgery because of broken mitral valve, and the APS who needed a heart transplantation because of severe dilated cardiomyopathy. Symptomatic treatment in all patients with 3 patients under enzymatic replacement treatment (HD and Pompe). Conclusions cardiomyopathy is commonly associated with IMD, with the hyperthophic cardiomyopathy as the most frecuent one. Other heart involvement can be found (arrhythmia, progressive heart failure o postransplant complications), because of the evolution of the underlying disease or clinical deteroration after acute decompensations. We would like to highlight that neonatal screening facilitates an early diagnosis of some of these diseases (4 cases in our series) and can be the diagnostic key before or after cardiomyopathy manifestation, helping with therapeutic management or genetic counselling, taking into account that these entities have a high mortality (46% in our series).