Combined supravalvular aortic stenosis and hypertrophic subaortic stenosis: coexistence or association?

A 19-year-old male was found to have combined supravalvular aortic stenosis and hypertrophic subaortic stenosis. Two possible hypotheses with supportive evidence in the literature may explain this association: (1) long-standing fixed supravalvular aortic stenosis may result in secondary hypertrophic subaortic stenosis, and (2) infantile hypercalcemia, a condition closely related to supravalvular aortic stenosis, may also be involved by continuous inotropic stimulation in the pathogenesis of muscular hypertrophy and subaortic stenosis of the left ventricle. We tend to favor the second theory in light of recent evidence in the literature.