Introduction: Absence of the posterior mitral leaflet is usually fatal for fetus in utero. Although hypoplasia of the posterior mitral leaflet is usually present in children with symptomatic mitral regurgitation, it is usually evident in a few cases of asymptomatic adults. We decided to introduce a rare case with hypoplasia of the posterior mitral valve leaflet associated with aortic stenosis.

Case Presentation: A 24-year-old man was admittedwith a history of atypical chest pain. The patient had a normal psychophysical growth. The physical examination showed 4/6 mid- systolic ejection murmurs over the left sternal border. Chest roentgenogram was normal and the electrocardiogram showed sinus rhythm with mild LVH. Meanwhile, the echocardiography revealed severe elongated sail- like anterior leaflet and hypoplasia of the posterior mitral leaflet with moderate valvular aortic stenosis. MR grade was mild due to the complete coverage of anterior mitral leaflet. Moreover, LV function and pulmonary arterial pressure were reported normal.

Conclusions: This abnormality was tolerated since adulthood and mitral regurgitation was gradually developed due to annulus dilation. Therefore, the posterior mitral leaflet did not have a significant impact on mitral valve performance.