PATTERN OF MALFORMATIONS IN THE AXIAL SKELETON IN HUMAN TRISOMY-21 FETUSES

In the present study, we analyzed the development of the axial skeleto n in human trisomy 21 fetuses and defined the fields in the axial skel eton affected in this form of aneuploidy. We investigated 31 human fet uses with trisomy 21, gestational ages 12-24 weeks, on the basis of ra diographs of midsagittal tissue blocks of the axial skeleton, comprisi ng the cranial base and the spine. Malformation or agenesis of the nas al bone was present in 19 of 31 fetuses, Nineteen cases had vertebral malformations. Fourteen fetuses had malformations in the cervical regi on, four in the thoracic and eight in the lumbosacral region. In 1 of 31 fetuses, malformation was seen in the basilar part of the occipital bone. The basisphenoid component appeared scallop-shaped in 30 cases. The pattern of axial skeletal malformations in trisomy 21 fetuses rec orded here has not been described previously. Comparison is made with our recent study of trisomy 18, where the pattern of axial skeletal ma lformations was quite different, It is recommended that axial skeletal radiography should be part of the autopsy of fetuses where chromosome abnormalities are known or suspected. (C) 1997 Wiley-Liss, Inc.