Detection and interpretation of two different cell lines in triploid abortions.

Among a series of 98 triploid abortions, there were four specimens with two cells lines. The detection of two clones was by Q-banding of chromosomes. Two of these four specimens were dizygotic twins, the third was either a mosaic or monozygotic twins with loss of a sex chromosome from one twin and the fourth was best explained as a chimaera which arose by fertilization of two female pronuclei by three sperms. These two unusual specimens had XYY sex chromosome complements which is rare among triploids. Two additional specimens were diagnosed clinically as possible twin pregnancies but only one cell line was identified from tissue culture. The frequency of twins was of the order of 1/33.