Pattern of malformations in the axial skeleton in human trisomy 21 fetuses

Abstract

In the present study, we analyzed the development of the axial skeleton in human trisomy 21 fetuses and defined the fields in the axial skeleton affected in this form of aneuploidy. We investigated 31 human fetuses with trisomy 21, gestational ages 12-24 weeks, on the basis of radiographs of midsagittal tissue blocks of the axial skeleton, comprising the cranial base and the spine. Malformation or agenesis of the nasal bone was present in 19 of 31 fetuses. Nineteen cases had vertebral malformations. Fourteen fetuses had malformations in the cervical region, 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 recorded here has not been described previously. Comparison is made with our recent study of trisomy 18, where the pattern of axial skeletal malformations 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.

Pattern of malformations in the axial skeleton in human triploid fetuses

“…The frequency and the character of the malformations seen in triploidy differed markedly from those reported in trisomies [Kjaer et al, 1996Keeling et al, 1997]. The most consistent type of axial skeletal malformation in the triploid fetuses was fusion of adjacent vertebral corpora seen in 6 fetuses.…”

“…The following 7 osseous axial regions or fields were analyzed: the sacral, lumbar, thoracic, and cervical vertebral segments of the spine, the basilar part of the occipital bone, the postsphenoid component of the sphenoid bone of the cranial base, and the nasal bones. These fields were defined in earlier studies on trisomy 18, 21, and 13 [Kjaer et al, 1996Keeling et al, 1997]. …”

Disruption of bone development and homeostasis by trisomy in Ts65Dn Down syndrome mice

“…The establishment of the appendicular skeleton begins early in prenatal development and continues through adolescence, and previous studies in humans have shown that individuals with trisomy have altered bone development both pre- and postnatally [8, 9]. Prenatal evidence suggesting changes in DS bone development has been derived from ultrasound measurements of the long bones [10].…”

Pattern of malformations in the axial skeleton in human trisomy 13 fetuses

“…The 2nd trimester axial skeleton in fetuses with trisomy 13 was not studied previously, although such studies were made in trisomy 18 and trisomy 21 Keeling et al, 1997]. Axial skeletal analysis in trisomy 13 demonstrates characteristic abnormalities in the lumbosacral spine, sphenoid, and nasal bones.…”

“…Investigation of the fetal axial skeleton in trisomy 18 and trisomy 21 showed that different fields were affected Keeling et al, 1997]. Therefore it seemed appropriate to investigate the axial skeleton in trisomy 13.…”