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Abstract: The platyspondylic lethal skeletal dysplasias (PLSD) are a group of heterogeneous disorders including thanatophoric dysplasia (TD) and the TD variants (San Diego, Torrance, and Luton types). TD is the most common form and has been divided into two subtypes (TD1 and TD2) based on clinical and radiologic criteria and analysis of mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. The variants are distinguished from TD by characteristic radiographic and chondro-osseous morphologic features. We have recently identified FGFR3 mutations in PLSD-San Diego type (PLSD-SD) which are identical to those found in TD1, but the known TD FGFR3 mutations were not found in the other PLSD variants. After reviewing radiographs from 32 cases of PLSD-SD and 47 cases of TD with gestational ages under 24 weeks, we noted novel accessory ossification centers in the ischia of 18 cases of PLSD-SD and 44 of TD, and the ilia in 18 cases of PLSD-SD and 20 of TD. Only three cases of TD and five cases of PLSD-SD did not have extra pelvic ossification centers. At a gestational age greater than 24 weeks, the extra centers are fused with the main bone. The radiographic appearance and chondro-osseous morphology of cases with and without accessory pelvic ossification centers were otherwise indistinguishable. Morphologically, the accessory pelvic ossification centers resulted from membranous ossification. Extra pelvic ossifications are a common radiographic finding in TD and PLSD-SD.

Abstract: The cervical spine is an especially important area, not only for the diagnosis of the skeletal dysplasias, but also for the management of the patient. By the “cervical spine” I refer not only to the vertebral bodies and posterior elements of this region, but also to the neural elements contained within, especially the cervical cord. The spine is supported by a group of ligaments both anteriorly and posteriorly, with special fixation of the odontoid and C2 by a ligament which normally affixes it firmly to C1. Multiple things may go wrong with the development of the cervical spine. There may be abnormal development of the “vertebrae” in this region, ranging from hypoplasia to developmental failure and/or abnormal ossification of the cervical vertebrae; associated or unassociated odontoid hypoplasia; poor ligamental fixation of C2 resulting in C1–2 subluxation; abnormal development of the posterior processes; abnormal ligamental development or laxity with abnormal cervical kyphosis or lordosis; and, in the case of more fragile/brittle bone development (osteoporosis or increased bone density), fractures can lead to cervical spine problems. The skeletal dysplasias that involve cervical spine problems constitute about 35 of the 150 well-described disorders. These include certain families of disorders like the type II collagenopathies, as well as many individual disorders. It is very important for the clinician to be able to pilot patients through the various appropriate imaging modalities – conventional radiographs of the cervical spine; lateral flexion/extension views; CT; MRI – so that proper management and therapy will result.

Abstract: We report a boy with mesomelic dysplasia of the forearms, skin dimples, mildly bowed tibiae, metatarsus adductus, congenital cataracts, sensorineural hearing loss, hypotonia, and mildly dysmorphic features. Prominent radiologic findings include bony spurs of the diaphyses of the radii bilaterally with angulated, significantly shortened radii and ulnae and elbow dislocations. Changes in the lower extremities are confined to bowing of the tibiae and elongation of the thinned fibulae. To our knowledge this case represents a unique combination of findings not previously reported, although some resemblance was found to a patient reported by Kozlowski et al. in 1993.

Abstract: The 2nd family with Sponastrime Dysplasia is described. The clinical, radiologic and chondro-osseous morphology of boy and girl siblings are presented. The facial appearance is an “oriental look” with midface hypoplasia and a saddle nose. The radiological findings include the spinal changes of lordosis, osteoporosis and pearshaped vertebrae, as well as striated metaphyses (osteopathia striata). The morphological findings suggest a disturbance in the formation of cartilage, with a defect in collagen and proteoglycans synthesis in this rare autosomal recessive skeletal dysplasia.

Abstract: Evaluation of the scapula can be useful in the diagnosis of skeletal dysplasias and helpful for the classification and delineation of new entities. A review of 2100 computerized cases of skeletal dysplasias in the International Skeletal Dysplasia Registry was performed. We found that the Luton type of platyspondylic lethal skeletal dysplasia differed radiographically from the San Diego type and Torrance type by the presence of two spikes at the inferior angle of the scapula. Hypoplasia of the body of the scapula, which is characteristic for campomelic dysplasia but not for kyphomelic dysplasia, is also present in Antley-Bixler syndrome. Radiographic and clinical similarities between campomelic dysplasia and Antley-Bixler syndrome suggest that they might be related disorders and that the latter condition should be included in the bent-bone dysplasia group. Similarity between the metaphyseal regions of the scapula and the metaphyses of the long tubular bones in the different types of short-rib polydactyly syndrome illustrates the importance of evaluation of the scapula in this group as well as in other well-defined or unknown osteochondrodysplasias.

Abstract: Analysis of 20 cases of metaphyseal chondrodysplasia, Schmid type as well as a review of the world literature reveals a specific autosomal dominant disorder that was often over-diagnosed in the past, sometimes resulting in incorrect genetic counselling. Significant radiologic features include an enlarged capital femoral epiphysis in early childhood, coxa vara, greater involvement of the distal femoral metaphysis than the proximal, anterior rib changes and a normal spine. Chondroosseous morphology is not specific. Presentation in nonfamilial cases is no earlier than the second year of life.

Abstract: Objective. To assess the role of coronal and sagittal vertebral clefts in diagnosing skeletal dysplasias. Material and Methods. A search in the database at the International Skeletal Dysplasia Registry revealed 40 different diagnoses in which coronal or sagittal clefts were present, the major groups being: atelosteogenesis, chondrodysplasia punctata, dyssegmental dysplasia, Kniest dysplasia and short rib polydactyly syndrome. We reviewed all firm cases with both AP and lateral films of the spine in these major groups (n = 143), with patients' ages ranging from 20 weeks of gestation up to 26 years of age. Results. Ninety-four percent of all clefts were found in children less than 1 year of age, mainly located in the thoracolumbar region. Fifty-six percent of the clefts were observed in boys. Coronal clefts were more common than sagittal clefts. Clefts were most frequently observed in atelosteogenesis (88 %), followed by chondrodysplasia punctata (79 %), dyssegmental dysplasia (73 %), Kniest dysplasia (63 %) and short rib polydactyly syndrome (53 %). Conclusion. Vertebral clefts are of major diagnostic value in the groups mentioned above, especially before 1 year of age. The search did not come up with new entities in which vertebral clefts are of major diagnostic value.

Abstract: We present two unrelated cases with a similar pattern of multiple congenital anomalies including limb shortening, long bone angulation, and cervical lymphocele. We believe these cases to represent additional examples of a syndrome first described by Cumming et al. (1986), and by Urioste et al. (1991) and Ming et al. (1997).

Mid-cervical kyphosis in diastrophic dysplasia (DD) with cord compression and weakness has been recognized for the last three decades. A strikingly similar situation exists in Larsen's syndrome (LS), an otherwise unrelated problem of weakness with lay joints and dislocations with typical facies. Forty patients with DD were studied of whom seven had cervical spine kyphosis: one patient had spontaneous correction over the ensuing two decades. Seven patients with LS were studied of whom four had cervical spine changes with cord compression. There was one sudden death among the patients with LS and no cases of spontaneous correction. Muscle weakness in DD and LS should lead to evaluation of cervical spine kyphosis with cord compression. Plain films, CT and recently MRI are useful.

The skeletal dysplasias (osteochondrodysplasias) comprise a heterogeneous group of disorders that are characterized by generalized abnormalities of skeletal growth and development. Of approximately 125 well-described skeletal dysplasias, about 50 are clinically apparent and identifiable at birth. The prevalence of these dysplasias in the newborn is quite frequent and has been estimated to be between 3–4.5 per 10,000, and the overall frequency of skeletal dysplasias among perinatal deaths to be about 9 per 1,000. Over the past 23 years we have acquired an enormous experience in the International Skeletal Dysplasia Registry with skeletal dysplasias diagnosable at birth or earlier. More and more cases referred to the registry over the past 2 years have been diagnosed as abnormal by ultrasound during the second trimester. The results of our evaluation of almost 400 fetuses and stillborn babies with reference to detailed prenatal history and postmortem evaluation including radiographs, chondro-osseous morphology and even some biochemical and molecular studies are presented. The most common disorders diagnosed were osteogenesis imperfecta (OI), thanatophoric dysplasia, campomelic dysplasia and achondrogenesis type II. Twenty-two types of neonatally diagnosable skeletal dysplasias are discussed together with potential fetal (second trimester) ultrasound findings, the number of fetal ultrasound cases referred to this registry, the number of total cases of that disorder sent to our registry, and the inheritance pattern of that skeletal dysplasia. This information should prove helpful in the evaluation of future cases ascertained by ultrasonography in the second trimester.

Clinical, radiographic and morphologic analysis of nineteen cases of perinatal (lethal) hypophosphatasia was performed. Three families each had two affected offspring. All of the patients had lethal short limb dwarfism with very soft calvaria. Other clinical findings included polyhydramnios, blue sclerae and spurs in the mid-portion of the forearms and lower legs. Considerable variability was found in the skeletal radiographs. In addition to the well known radiographic features such as generalized decrease in the size of ossified bones with some bones not ossified at all, other changes observed included: 1) marked variability in the amount of bone ossification; 2) variability between patients as to which bones were most severely affected; 3) unusually dense, round, flattened, butterfly shaped; and saggitally clefted vertebral bodies; 4) variability in femoral shape including “chromosome” like, “campomelic” like, and shortening with or without metaphyseal cupping or irregularities; 5) osteochondral projections (Bowdler spurs) of the midshaft of the fibula and ulna. Recognition of the marked clinical and radiographic variability in this autosomal recessive lethal skeletal dysplasia is important for accurate genetic counseling and prenatal diagnosis.

Abstract: Objective. The objective of this study was to review the problem of lumbar gibbus in children with storage diseases and bone dysplasias utilizing plain films and MR imaging. Materials and methods. Clinical histories and radiographic images in five patients with storage diseases [four mucopolysaccharidosis (MPS) and one mucolipidosis] and two with achondroplasia were reviewed. The International Skeletal Dysplasia Registry (Los Angeles, Calif.), surveyed for all patients with lumbar gibbus and skeletal dysplasias, provided 12 additional cases. Results. All patients had localized gibbus of the upper lumbar spine, characterized by anterior wedging and posterior displacement of the vertebrae at the apex of the curve, producing a beaked appearance. The curve, exaggerated in the sitting or standing position, was most severe in the two patients with MPS-IV (one of whom died). Both developed severe neurologic signs and symptoms requiring surgical intervention. In four patients, MR images demonstrated the apex of the curve to be at or below the conus. Two patients demonstrated anterior herniation of the intervertebral discs at the apex of the curve, though the signal intensity of the intervertebral discs was normal. Conclusion. Lumbar gibbus has important neurologic and orthopedic implications, and is most severe in patients with MPS. The etiology of the gibbus with vertebral beaking is multifactorial and includes poor truncal muscle tone, weight-bearing forces, growth disturbance and anterior disc herniation. The curve is generally at or below the conus. Neurologic complications are unusual, although orthopedic problems can arise. Due to their longer survival, patients with achondroplasia or Morquio's disease are more vulnerable to eventual gibbus-related musculoskeletal complications.

The case report is presented of a neonate with a unilateral multicystic dysplastic kidney. An intravenous pyelogram revealed septations throughout this kidney with late pooling of contrast media within the cystic structures. The pathological data stresses the presence of normal appearing glomeruli interspersed between the dysplastic cystic parenchyma. The possible etiologies for the septation sign and puddling phenomenon are discussed.