Sisters with polysplenia.

The pathogenesis of asplenia and polysplenia in humans is unknown. The conditions have been regarded as duplication of sidedness or abnormalities of embryonic curvature. The resemblance of the abnormalities in an autosomal recessive mutation (iv) in mice to those in humans with asplenia or polysplenia suggest the possibility of a genetic basis for asplenia/polysplenia in humans. We have studied a family in which two sisters had polysplenia, one sib pregnancy resulted in abortion, and two sibs and the parents are living and well with no evidence of the condition. Documentation of such families will be of value in determining the variations in expression of the condition and possible relationship between asplenia and polysplenia.