ABSTRACT
Costello syndrome is a rare syndrome associated with de novo mutations in the HRAS gene. It is mostly revealed during in the first months of life by growth retardation, facial dysmorphic features, skin and cardiac abnormalities and subsequent cognitive deficit of varying severity. We report a case of Costello syndrome in a 3-month-old infant. The initial cardiac investigations were normal except frequent premature atrial complexes. After few months, worsening arrhythmia with bursts of ventricular tachycardia were noted as well as the secondary progressive obstructive left ventricular hypertrophic cardiomyopathy [HCM]. Cardiac involvement is determinant for the prognosis of Costello syndrome. It frequently consists of hypertrophic cardiomyopathy [one third of patients], with involvement of the left ventricle in half of the cases. It is often asymmetrical and associated with obstruction of the outflow recalling family hypertrophic cardiomyopathy. The natural history of HCM in Costello syndrome and its management remains poorly known because of paucity of reported cases. Progression of the HCM can be very rapid like the reported case. On the other hand, the spontaneous regression of the HCM in some patients has been reported. In addition, cardiac threatening arrhythmias may be noted. So that, cardiac assessment and monitoring with regular echocardiography and electrocardiogram follow up is mandatory