Familial clustering of situs inversus totalis, and asplenia and polysplenia syndromes.

We report on a family in which a male infant had the asplenia syndrome, a younger brother had the polysplenia syndrome, and their father had situs inversus totalis. The occurrence of the asplenia and the polysplenia syndromes in a sibship of the present family and in two other previously reported sibships indicates that the two syndromes are causally and pathogenetically related to each other. If it is assumed that the father had an incomplete form of the polysplenia complex, then the condition in this family either is an autosomal dominant trait or is multifactorially determined.