Fixed subaortic stenosis associated with hypertrophic cardiomyopathy: report of a rare familial occurrence.

Introduction: Fixed subaortic stenosis is considered to be an acquired condition. It is often associated with congenital heart disease, creating a turbulence in the left ventricle outflow tract. Familial forms of fixed subaortic stenosis are very unusual. We report a remarkable familial cluster in which fixed subaortic stenosis is associated with hypertrophic cardiomyopathy.
Methods: Fourteen relatives of a patient affected with hypertrophic cardiomyopathy and fixed subaortic stenosis underwent cardiological examination, electrocardiogram and echo-doppler study.
Results: Two of the proband's sisters showed an association between asymmetrical hypertrophic cardiomyopathy and fixed subaortic stenosis. The brother presented a subaortic ridge and concentric left ventricular hypertrophy. The other members of the family (another brother and the third-generation relatives) were unaffected.
Conclusions: While the association between fixed subaortic stenosis and hypertrophic cardiomyopathy has commonly been reported, there is little in the literature to suggest the family-related nature of this association. The familial occurrence of this association reveals genetic transmission, with a recessive autosomal pattern of inheritance. This finding goes against the usual autosomal dominant pattern of inheritance in hypertrophic cardiomyopathy. Familial studies of FSS are needed in order to gain a better understanding of the genetic background of these patients.