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Lethal osteosclerotic skeletal dysplasia with intracellular inclusion bodies
S G Brodie1, R S Lachman, M M McGovern
1Ahmanson Department of Pediatrics, Steven Spielberg Pediatrics Research Center, Cedars-Sinai Burns and Allen Research Institute, Los Angeles, California, USA.
Abstract:
We report an apparently previously undescribed form of lethal osteosclerotic skeletal dysplasia in a 30-week male fetus with micromelic shortness of the limbs. Radiographic findings at necropsy included increased density in all bones, most marked in the skull, mandible, and pubis. The ribs were very short, abnormally modeled, and wide anteriorly. The vertebrae were posteriorly hypoplastic and wedged, particularly in the cervical and lumbar regions. The femora and tibiae were short with wide distal metaphyses, undermodeled diaphyses, and coxa vara. The humeri, radii, and ulnae were also short and undermodeled with proximal and distal flare. Chondro-osseous morphology showed short chondrocyte columns, extension of hypertrophic cells into the metaphysis, and overgrowth of perichondral bone. In the resting cartilage there were large chondrocytes containing a homogeneous material staining pink with von Kossa trichrome, gray with toluidine blue, and black with silver methenamine. The cortical bone was lacking and the trabecular bone was hypercellular, thick, and coarse. Ultrastructurally, the resting zone chondrocytes were large and round with condensed chromatin and dilated loops of rough endoplasmic reticulum. The radiographic and histopathologic findings in this case are unique and differ from those seen in other reported lethal osteosclerotic skeletal dysplasias.
Insights
This study describes a new lethal osteosclerotic skeletal dysplasia in a fetus, characterized by severe limb shortening and unique bone density abnormalities. The findings are distinct from previously documented skeletal dysplasias.
Area of Science:
- Skeletal Dysplasias
- Fetal Pathology
- Osteosclerosis
Background:
- Osteosclerotic skeletal dysplasias are a group of rare genetic disorders.
- Accurate diagnosis is crucial for genetic counseling and understanding disease mechanisms.
Observation:
- A 30-week male fetus presented with micromelic limb shortening and generalized osteosclerosis.
- Radiographic and necropsy findings revealed severe skeletal abnormalities, including hypoplastic vertebrae and undermodeled long bones.
Findings:
- Histopathology showed abnormal chondrogenesis with short chondrocyte columns and hypertrophic cell extension.
- Unique ultrastructural features in resting zone chondrocytes were observed.
- Cortical bone was deficient, and trabecular bone was hypercellular and coarse.
Implications:
- This case represents a previously undescribed form of lethal skeletal dysplasia.
- The unique radiographic and histopathologic features expand the spectrum of known skeletal dysplasias.
- Further research may elucidate the genetic basis and pathogenesis of this condition.