Skeletal dysplasias

Abstract

The skeletal dysplasias are a group of more than 450 heritable disorders of bone. They frequently present in the newborn period with disproportion, radiographic abnormalities, and occasionally other organ system abnormalities. For improved clinical care, it is important to determine a precise diagnosis to aid in management, familial recurrence, and identify those disorders highly associated with mortality. Long-term management of these disorders is predicated on an understanding of the associated skeletal system abnormalities, and these children are best served by a team approach to health care surveillance.

Keywords: Achondroplasia; Nonassortive mating; Osteochondrodysplasias; Osteogenesis imperfecta; Skeletal dysplasias; Type II collagenopathies.

Figure 1

Scheme of management in newborns with a skeletal dysplasia

Figure 2

Radiographs of FGFR3 disorders. A. Thanatophoric dysplasia in the newborn period. Note the small chest, severe rhizo-mesomelia, curved femora with proximal fadeout and distal irregularities. B. 32 week fetus with achondroplasia. Note the relatively mild narrowing of the chest, rhizomelia and fade-out of the proximal femora (arrow).

Figure 3

Radiographs of type II collagen disorders. A. Achondrogenesis II in the late second trimester. Note the severe rhizo- and mesomelia with relative sparing of the hands, lack of ossification of the vertebral bodies and absent ischia. B. Hypochondrogenesis in the late second trimester. Vertebral bodies are under ossified with dumb-bell shaped humeri and femora, and lack of ossification of the ischia.

Figure 4

Radiographs of spondylo-epiphyseal dysplasia congenital (SEDC) in the newborn period. A. A/P view of the chest showing bell shaped chest with normal appearance of the rib ends, subjective platyspondyly and lack of ossification of the pubis. B. Lateral xray showing delayed ossification of the base of the skull, short ribs, and platyspondyly.

Figure 5

Radiographs of Osteogenesis Imperfecta (OI). A. Perinatal lethal OI showing complete under mineralization of the skeleton with crumbled appendicular bone due to recurrent fractures and poor healing. B. Lateral skull of a newborn with OI. Note poor ossification of the calvarium, visualization of the anterior fontanel and wormian bones. C. A/P of the chest showing narrowness and rib fractures (arrow). D. A/P lower extremities showing poorly modeled and under-mineralized long bones, crumbled appearance due to recurrent fractures.