Probable autosomal recessive inheritance of polysplenia, situs inversus and cardiac defects in an Amish family.

We report on an Amish family with five individuals in two generations with complex congenital heart disease. Autopsy findings in one and clinical examination in the others support the diagnosis of polysplenia "syndrome." In a mouse model, this spectrum of situs abnormalities and cardiovascular defects shows recessive inheritance with homozygotes having either situs solitus or situs inversus or ambiguous situs. The parents of the four affected sibs are fourth cousins. We think that the father of these four children is an affected but clinically normal homozygote, that his deceased sister was an affected homozygote, and it seems likely that they too had consanguinous parents.