Recombinant chromosome 18 in two offspring of a chromosome 18 inversion heterozygote.

A case of partial trisomy of chromosome 18 due to a recombinant pericentric inversion is described. Prenatal diagnosis in a subsequent pregnancy identified a foetus with the recombinant chromosome 18, and the pregnancy was terminated. A comparison is made between the risks reported in the relevant literature where recombinant offspring have resulted from chromosome 18 inversion heterozygotes and those observed in this case.