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Autopsy case of microcephalic osteodysplastic primordial "dwarfism" type II
Ryuji Fukuzawa1, Seiji Sato, Michael J Sullivan
1Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan. ryuji.fukuzawa@stonebow.otago.ac.nz
Abstract:
Microcephalic osteodysplastic primordial "dwarfism" (MOPD) is a group of disorders similar to Seckel syndrome. Three subtypes (types I-III) have been reported. We report here the first autopsy case of MOPD type II. The patient was a Japanese girl with typical clinical and radiological manifestations of MOPD type II. The manifestations included severe intrauterine and postnatal growth failure, microcephaly, a distinctive facial appearance, micromelia, brachytelephalangy, coxa vara, and V-shaped metaphyses of the distal femora. Other than small cerebral hemispheres, no neuropathological abnormalities were found. Chondro-osseous histology showed thinning of the growth plate, ballooned chondrocytes, reduced cellularity, lack of zonal and columnar formations, and poor formation of primary trabeculae. These findings suggest that impairment of chondrocytic formation and differentiation is the major pathogenesis of MOPD type II.
Insights
Microcephalic osteodysplastic primordial dwarfism (MOPD) type II is a rare genetic disorder. Autopsy findings reveal growth plate abnormalities, suggesting impaired chondrocyte development as the primary cause.
Area of Science:
- Genetics
- Pathology
- Pediatrics
Background:
- Microcephalic osteodysplastic primordial dwarfism (MOPD) encompasses rare genetic disorders characterized by severe growth retardation.
- Three subtypes, including MOPD type II, are recognized, often exhibiting features similar to Seckel syndrome.
Purpose of the Study:
- To present the first autopsy case report of MOPD type II.
- To elucidate the underlying pathogenesis of MOPD type II through detailed histopathological examination.
Main Methods:
- Autopsy of a Japanese female infant with clinical and radiological features of MOPD type II.
- Comprehensive neuropathological examination.
- Detailed chondro-osseous histological analysis of growth plates.
Main Results:
- The patient exhibited typical MOPD type II manifestations: severe intrauterine/postnatal growth failure, microcephaly, distinctive facial features, micromelia, and skeletal anomalies.
- Neuropathology revealed only small cerebral hemispheres without other abnormalities.
- Chondro-osseous histology demonstrated a significantly thinned growth plate with ballooned chondrocytes, reduced cellularity, and disorganized chondrocyte arrangement.
Conclusions:
- Impaired chondrocytic formation and differentiation are identified as the primary pathogenic mechanism in MOPD type II.
- This case provides crucial insights into the skeletal pathology of MOPD type II, aiding in understanding its developmental basis.