Congenital malformations of the tricuspid valve in siblings.

The occurrence of familial heart disease in association with tricuspid atresia is rare. The first reported instance of tricuspid atresia and Ebstein's anomaly in siblings is presented. The presence of these two distinct pathologic variants of tricuspid valve malformations in siblings suggests that these malformations result from a common abnormality occurring during the development of the inlet portion of the right ventricle.