We report the case of a 22-year-old woman in whom a focal aplasia of the pulmonary valve annulus associated with a multiple aneurysmal compensatory dysplasia was found. This patient had been followed since the age of seven years for a congenital asymmetric hypertrophic cardiomyopathy. Cardiac Doppler analysis showed significant pulmonary valvular insufficiency. The patient underwent heart transplant surgery because of total and refractory cardiac insufficiency. Pathological examination of the explanted heart enabled us to describe this valvular malformation. Whether this anomaly is a malformation discovered fortuitously, or is responsible in part for some signs associated with congenital hypertrophic cardiomyopathy remains unclear. However, its role might be disclosed by a rigorous investigation of the patient's family.