We have observed a distinct form of ''crossed'' polysyndactyly in 6 ge
nerations of a family with 5 affected persons, all males. The polydact
yly is postaxial in the hands and preaxial in the feet. Syndactyly in
the hands is observed in some relatives, while syndactyly in the feet
is present bilaterally in all affected relatives. This seems to be an
autosomal dominant trait with male to male transmission over 3 generat
ions by examination and an additional 3 generations by history. This f
orm of polysyndactyly could not be readily categorized by the existing
classification by Temtamy and McKusick [1978: BD OAS XIV 6:363-392].
We review and expand the present classification of polydactyly and syn
dactyly syndromes. (C) 1994 Wiley-Liss, Inc.