Opsismodysplasia is a rare skeletal dysplasia involving delayed bone maturation. Clinical signs observed at birth include short limbs, small hands and feet, relative macrocephaly with a large anterior fontanel, and characteristic craniofacial abnormalities including a prominent brow, depressed ... Opsismodysplasia is a rare skeletal dysplasia involving delayed bone maturation. Clinical signs observed at birth include short limbs, small hands and feet, relative macrocephaly with a large anterior fontanel, and characteristic craniofacial abnormalities including a prominent brow, depressed nasal bridge, a small anteverted nose, and a relatively long philtrum. Death secondary to respiratory failure during the first few years of life has been reported, but there can be long-term survival. Typical radiographic findings include shortened long bones with very delayed epiphyseal ossification, severe platyspondyly, metaphyseal cupping, and characteristic abnormalities of the metacarpals and phalanges (summary by Below et al., 2013).
Opsismodysplasia was suggested by Maroteaux et al. (1982) as the designation for a skeletal dysplasia that shows late bone maturation; the Greek root for the first part of the word means 'delayed maturation.' The disorder was observed at ... Opsismodysplasia was suggested by Maroteaux et al. (1982) as the designation for a skeletal dysplasia that shows late bone maturation; the Greek root for the first part of the word means 'delayed maturation.' The disorder was observed at birth; predominantly rhizomelic micromelia, facial dysmorphia, prominent brow, large fontanels, depressed nasal bridge, small anteverted nose with long philtrum, and short feet and hands with sausage-like fingers were features. Death from pulmonary infection was frequent. Growth of the limbs and vertebrae was slow. One patient, aged 3 years and 9 months, showed no femoral, tibial, or carpal nuclei. Maroteaux et al. (1982) studied 4 cases. They referred to a fifth possible case reported by Zonana et al. (1977). One set of parents had ages 44 and 38; consanguinity in other cases suggested autosomal recessive inheritance. Consistent with the designation, the characteristic radiographic signs include very retarded bone maturation, as well as marked shortness of the bones of the hands and feet with concave metaphyses and thin, lamellar vertebral bodies. In studies of the growth cartilage in 1 case, Maroteaux et al. (1984) found a wide hypertrophic area containing thick connective tissue septa, irregular provisional calcification, and vascular invasion. Type I collagen was detected in the hypertrophic area by immunohistochemical and microchemical tests. Beemer and Kozlowski (1994) described the disorder in a 2-year-old boy with first-cousin parents. At 16 months, there were no carpal or tarsal ossification centers and the bones of the hands and feet showed severe abnormalities. There was also absence of ossification in the distal femur and proximal tibia. Santos and Saraiva (1995) described a typical case in a Portuguese male infant born to consanguineous parents. Macrostomia was the only finding in this patient that had not previously been reported in this disorder. Cormier-Daire et al. (2003) described 12 cases in 9 families, all of which had major delay in epiphyseal ossification, platyspondyly, metaphyseal cupping, and very short metacarpals and phalanges. Six cases were diagnosed by prenatal ultrasound and the pregnancies were terminated; of the 6 other cases, one died at 3 months of age of respiratory illness, but the other 5 were still alive and were aged 28 months to 15 years, demonstrating that patients with this disease can survive well beyond the neonatal period. Initial radiographic findings were characteristic of the disease; x-ray follow-up of the survivors showed persistence of an extremely delayed epiphyseal ossification with dysplastic carpal ossification, marked shortness of the metacarpals, and metaphyseal irregularities in the knee. Histopathologic examination of fetal bones and cartilage showed wide and numerous epiphyseal vascular canals; chondrocyte density in the resting cartilage was increased, many cells were arranged in clusters, and some of them were ballooned. At the growth plate level, the proliferative zone was very disorganized, with a nearly absent columnar organization. The mineralized matrix trabeculae were thick and irregular. These anomalies were observed in all cases but varied markedly in severity among cases, paralleling the variability of the x-ray manifestations.