Morphology of early intrauterine deaths with full trisomy 15.

OBJECTIVE: The morphologic features of embryos with full trisomy 15 are described.

METHOD: A total of 1195 pregnancy losses were examined embryoscopically and cytogenetically.

RESULTS: Of 1173 successfully karyotyped specimens, full trisomy 15 was diagnosed cytogenetically in 59 cases (5%). All 59 trisomy 15 embryos were diagnosed cytogenetically in the group of 962 embryonic miscarriages (6%). Trisomy 15 was not registered in 171 anembryonic or yolk sac miscarriages, and no case of full trisomy 15 was observed in 62 fetal miscarriages. Fifty-eight embryos with full trisomy 15 showed structural defects on embryoscopic examination. The most common defects were craniofacial anomalies (n = 73), retarded development of the limbs (n = 39), and abnormally short umbilical cords closely attaching the embryo to the chorionic plate (n = 27). Seven embryos were classified as growth disorganized. Limb reduction defects with a prevalence of 5.6/10 000 births, all affecting upper limb development (10 terminal transverse limb reduction defects and 3 embryos with split hand), were registered in 13 (22%) trisomy 15 embryos.

CONCLUSION: Limb reduction defects and craniofacial abnormalities are a typical feature of trisomy 15. Gene dosage imbalances related to trisomy 15 might be the main molecular mechanism underlying the developmental defects observed in the present study and require further investigation.