Molecular studies of the aetiology of trisomy 8 in spontaneous abortions and the liveborn population

摘要

We have determined the parental origin in eight cases of constitutional trisomy 8. In all four cases of spontaneous abortion, the additional chromosome was maternal in origin and there was evidence for nullichiasmate meiosis I occurring in the genesis of this trisomy. In contrast, all four cases of liveborn trisomy 8 appear to have arisen by a mechanism consistent with the post-zygotic mitotic gain of the additional chromosome.