Abstract

Costello syndrome is a rare congenital disease caused by activating germline mutations, and it is often associated with cardiac abnormalities. A 17-year-old male, who had a history of Costello syndrome, presented with persistent fever. The vegetation attached to anterior mitral leaflet was detected, and antibiotic therapy was administered as treatment for infectious endocarditis. However, it was difficult to manage his heart failure owing to the worsening of mitral valve regurgitation. Therefore, mitral valve repair with vegetation resection was performed. His hypertrophic cardiomyopathy and systolic anterior motion caused left ventricle outflow tract obstruction. A floating stitch on the anterior mitral leaflet from the posterior ring annulus was effective. Herein, we report a successfully repaired case of infectious endocarditis on the mitral valve with hypertrophic cardiomyopathy complicated by Costello syndrome.