Acetabular dysplasia with hip subluxation in Trevor's disease of the hip

Dysplasia epiphysealis hemimelica (Trevor's disease) is a rare developmental bone disorder characterized by single or multiple epiphyseal intraarticular lesions that are usually unilateral and restricted to one side of the limb. Although the process often is limited to the lower extremity, hip involvement is not common. When it occurs it is more commonly limited to the femoral side. We report a 14-year-old boy with Trevor's disease involving the hip, femoral and acetabular sides, and with progressive dysplasia. We describe a new surgical approach to this rare condition using a two-stage procedure consisting of intraarticular resection of the lesion followed by a modified shelf acetabuloplasty in a second stage to prevent compromise of the proximal femur vasculature, and to allow preservation and improvement of range of motion of the hip. At 36 months followup the patient is pain-free, has full range of motion, improved gait, and no signs of recurrence. Although technically challenging, the two-stage approach to Trevor's disease seems a reasonable and safe method.

FGFR3 mutations and medial temporal lobe dysgenesis

The authors describe a child who has hypochondroplasia due to an N540K mutation and who has medial temporal lobe dysgenesis. This association has been reported only twice before. FGFR3 is expressed in the brain during development and plays a role in hippocampal formation, and FGFR3 mutations could cause cerebral malformations in hypochondroplasia. Further neuroimaging studies of patients with hypochondroplasia and epilepsy or developmental delay may clarify the proportion of patients with hypochondroplasia with this pattern of central nervous system abnormalities.

Immunohistochemical Examination of Epiphyseal Growth Plates of Japanese Brown Cattle with Chondrodysplasia

A new type of inherited chondrodysplasia is described in Japanese Brown cattle, but the basic defects of the epiphyseal growth plate (EGP) in the limb long bones, and proliferation and differentiation of the chondrocytes in the EGP, are not yet understood. In the present study, the EGPs of the limb long bones in eight cases of chondrodysplasia and four normal (control) cattle were examined histologically and immunohistochemically. In the control cattle, proliferative chondrocytes (PCs) and hypertrophic chondrocytes (HCs) were arranged in columns parallel to the long axis of the bone, and HCs were situated on the metaphyseal side of the EGP. In all the affected cattle, many chondrocytes with a hypertrophic appearance were detected in the inner areas of the central portion of the EGP. The PC columns were short and arranged irregularly. Bone tissue and small blood vessels were found frequently in these areas. Six affected cattle showed complete EGP-closure. Backscattered electron (BSE) imaging showed that the calcified cartilage matrix was restricted to the lower region of the hypertrophic zone (HZ) of the EGP in the control cattle, while the calcified cartilage matrix and bone tissue were scattered in the inner areas of the EGP in all the chondrodysplastic cattle. Immunohistochemistry revealed type X collagen in the HCs and cartilage matrix of the HZ in the control cattle. In all the affected cattle, type X collagen was detected in apparently hypertrophic chondrocytes in the inner areas of the EGP. Type II collagen was detected in the entire EGP in all the affected cattle, as in the controls. BrdU (5-bromo-2'-deoxyuridine), injected intravenously 1h before euthanasia was detected in many PCs in the EGP in the control cattle; none, however, was detected in the central portion of the EGP in any affected animal. These observations indicate that differentiation into HCs and calcification of cartilage matrix occur in the inner areas of the central portion of the EGP in chondrodysplasia of Japanese Brown cattle. Differentiation into the HCs at this abnormal site may be caused by the inadequate proliferation and disorganization of the PCs. Premature EGP-closure, observed commonly in chondrodysplasia of Japanese Brown cattle, was thought to be caused by replacement of the calcified cartilage in the inner areas of the EGP by bone tissue.

Phenotypic overlap in Melnick-Needles, serpentine fibula-polycystic kidney and Hajdu-Cheney syndromes: a clinical and molecular study in three patients

Several disorders characterized primarily by anomalies of the skeleton have recently been shown to be caused by mutations in the X-linked gene, FLNA. One of these conditions, the Melnick-Needles syndrome exhibits a phenotype that shares overlap with that of serpentine fibula-polycystic kidney syndrome and the autosomal dominant condition, Hajdu-Cheney syndrome. Here, we describe three individuals with these diagnoses. The individual with serpentine fibula-polycystic kidney syndrome, the fifth case reported in the literature, exhibited wormian bones which further expands the phenotypic spectrum for this condition and extends the overlap with Hajdu-Cheney syndrome. All three members of the filamin gene family, FLNA, and its functionally related paralogues, FLNB and FLNC, were screened for pathogenic mutations in all three individuals. We found a mutation in FLNA in the individual with Melnick-Needles syndrome, but no pathogenic variants in any filamin gene in the two individuals with Hajdu-Cheney syndrome and serpentine fibula-polycystic kidney syndrome. Clinical and molecular evidence indicates that Melnick-Needles syndrome is aetiologically distinct from Hajdu-Cheney syndrome and serpentine fibula-polycystic kidney syndrome, but these two latter conditions share many clinical similarities and may prove to be allelic to one another.

COL2A1–related skeletal dysplasias with predominant metaphyseal involvement

Skeletal dysplasias induced by mutations in the collagen 2 gene (the so-called "type 2 collagenopathies") form a wide spectrum in severity and are distinguished by subtle clinical and radiographic differential signs. The unifying features are predominant involvement of the vertebral bodies and the epiphyses of the long bones ("spondylo-epiphyseal" pattern). A mild degree of metaphyseal dysplasia can be seen in the so-called Strudwick variant of spondyloepimetaphyseal dysplasia and is generally mild or absent in other forms. We report here on four individuals with COL2A1 mutations associated with marked metaphyseal involvement with only mild epiphyseal and spondylar changes. One patient who carried a Gly283Arg substitution had a pattern of metaphyseal dysplasia that corresponded precisely to what was termed "Murdoch type metaphyseal dysplasia" in 1960s and was renamed Strudwick type SEMD in 1980s; the second patient carried a Gly181Arg substitution and had severe metaphyseal dysplasia with fractures at the metaphyses reminiscent of the "corner fractures" or Sutcliffe type spondylometaphyseal dysplasia. The third patient also had major metaphyseal involvement but more epiphyseal changes than the others in this study and had a Gly922Arg mutation in COL2A1. The final patient had a small in-frame deletion and unusually ballooned and distorted metaphyses. While it remains true that most individuals with COL2A1 mutations have chondrodysplasia with a spondylo-epiphyseal pattern, metaphyseal involvement is not incompatible with a COL2A1 dysplasia and mutation analysis can be indicated. The observation of these individuals with metaphyseal dysplasia indicates that the phenotypic spectrum associated with mutations in type 2 collagen, the main cartilage protein, is even wider than hitherto assumed.

Reduced perlecan in mice results in chondrodysplasia resembling Schwartz-Jampel syndrome

Perlecan knock-in mice were developed to model Schwartz-Jampel syndrome (SJS), a skeletal disease resulting from decreased perlecan. Two mouse strains were generated: those carrying a C-to-Y mutation at residue 1532 and the neomycin cassette (C1532Yneo) and those harboring the mutation alone (C1532Y). Immunostaining, biochemistry, size measurements, skeletal studies and histology revealed Hspg2 transcriptional changes in C1532Yneo mice, leading to reduced perlecan secretion and a skeletal disease phenotype characteristic of SJS patients. Skeletal disease features include smaller size, impaired mineralization, misshapen bones, flat face and joint dysplasias reminiscent of osteoarthritis and osteonecrosis. Moreover, C1532Yneo mice displayed transient expansion of hypertrophic cartilage in the growth plate concomitant with radial trabecular bone orientation. In contrast, C1532Y mice, harboring only the mutation associated with SJS, displayed a mild phenotype, inconsistent with SJS. These studies question the C1532Y mutation as the sole causative factor of SJS in the human family harboring this alteration and imply that transcriptional changes leading to perlecan reduction may represent the disease mechanism for SJS.

Camptomelic dysplasia: A case report

Campomelic/camptomelic dysplasia is a very rare, severe osteochondrodysplasia characterised by severe skeletal and nonskeletal malformations and lethal outcome mainly in neonatal period. Characteristic abnormality by which the syndrome got its name is short, bowed long bones of lower extremities, most often of femur, manifested by short and bowed legs. Skin dimpling on tibial anterior side is another prominent characteristic of this syndrome. Severe cases are inherited by autosomal dominant trait, by mutation Sox9 gene on chromosome 17, with lethal outcome in the first days of life. Less severe forms of the disease are due to balanced translocation t (13;17) with life span up to the third decade of life. A majority of karyotypic males present as phenotypic females. We report a case of a female neonate, without consanguinity between parents, with characteristic signs of camptomelic dysplasia with short birth length of 46 cm, macrocephaly (head circumference 39 cm), dolichocephaly, hydrocephalus, short trunk and legs. Narrow rib cage, bowed lower extremities, short hand and foot phalanges, nail hypoplasia were noticed. Anterior fontanelle was enlarged, high forehead, face small and flat, hypertelorism, low nasal bridge, micrognathia, low set ears, cleft palate, were found. Characteristic skin dimpling on anterior side of tibia was present on both legs. Bone X-ray studies presented the following changes: anterior bowing of shortened femurs, hip dislocation, cervical vertebrae, scapulas, eleven pairs of slender ribs. Hip luxation. Karyotype was normal for a female, 46 XX. Respiratory insufficiency was present since birth, exacerbated, and led to lethal outcome in the second day of life, as described in the majority of these patients. .

Deformity correction with external fixator in pseudoachondroplasia

Patients with pseudoachondroplasia have complex, difficult to correct deformities including angular deformity, rotational deformity, and ligament laxity. We retrospectively reviewed seven patients (two children, five adults) with 26 segmental deformities (12 femora, 14 tibiae). We performed bilateral femoral and tibial osteotomies in six patients and bilateral tibial osteotomies in one patient. Distraction osteogenesis was used in 20 segments and acute deformity correction was done in six segments. External fixation was applied to all segments. Of 26 segments, there were five good, 12 fair, and nine poor radiographic results with nine major and 12 minor complications. Recurrent deformity in children and refracture in adults were related to poor results. Of 14 limbs, there were four good, five fair, and five poor clinical results with five major and 14 minor complications. Knee stiffness was the most common complication related to poor results in our series, and occurred particularly in patients with simultaneous correction of the ipsilateral tibial and femoral deformities. Therefore, two-stage surgery including bilateral tibial osteotomies first and then bilateral femoral osteotomies is recommended instead of simultaneous correction of the ipsilateral tibial and femoral deformities to avoid knee stiffness.

Mutant WISP3 triggers the phenotype shift of articular chondrocytes by promoting sensitivity to IGF-1 hypothesis of spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA)

This article introduces the hypothesis that mutant WISP3 (Wnt1 inducible secreted protein-3) triggers the phenotype shift of the chondrocytes, especially in the articular chondrocytes, by promoting sensitivity to IGF-1 (insulin-like growth factor 1), and results in chondrocytes apoptosis in SEDT-PA. SEDT-PA is also referred to as progressive pseudorheumatoid dysplasia (PPD), arthropathy progressive pseudorheumatoid of childhood (APPRC). Evidence for the hypothesis is based on the following indications: (1) SEDT-PA is caused by mutations of the WISP3 gene. WISP3 encodes a domain that bears homology to the amino-terminal domain of the insulin-like growth factor binding proteins (IGFBPs). (2) IGF-1 enhances chondrocyte hypertrophy by insulin-like actions. WISP3 can up-regulate the expression of type II collagen. When chondrocytes become hypertrophic, they reduce the expression of types II and IX collagen. (3) The chondrocytes in the normal articular cartilage maintain a stable phenotype. These cells exhibit no mitotic activity, low matrix synthesis and low degradation. But articular chondrocytes could react to certain stimuli such as IGF-1. (4) The loss of WISP3 expression alters the phenotype of the breast epithelium and promotes motility and invasion. The WISP3-deficient cells are extremely sensitive to the growth stimulatory effects of IGF-1. (5) The action of IGF-I is inhibited by IGFBPs, both in articular chondrocytes and in the normal breast epithelium. In conclusion, the mutant WISP3 lose is the function of inhibiting IGF-1 and disturbs the maintenance of a stable phenotype in articular chondrocytes. So, the articular chondrocytes undergo hypertrophic and terminal differentiation apoptosis. The precise mechanism of WISP3 function during postnatal cartilage growth and homeostasis is not clear yet. This hypothesis provides a new clue on the present mechanism study on SEDT-PA. If verified, this new concept may lead to a novel pathogenesis of SEDT-PA.

Nasu-Hakola disease (PLOSL): report of five cases and review of the literature

The combination of bilateral lytic lesions in the bones of the lower and upper extremities and presenile dementia is characteristic of polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, also known as Nasu-Hakola disease. The clinical course of this rare and fatal disorder is characterized by pathologic fractures of these often painful lesions, rapid progression of dementia, and death in the fifth decade of life. The radiographic changes may be confused with cystic angiomatosis, focal metastasizing hemangioendothelioma, or Langerhans' cell histiocytosis. We report five patients to illustrate the clinical presentation, radiographic images, psychiatric abnormalities, and new genetic findings. Three of the patients were siblings. A biopsy is not needed to confirm the diagnosis of polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy because of the unique combination of radiographic and neurologic features.

Histopathologic study of long-bone growth plates confirms the basset hound as an osteochondrodysplastic breed

Osteochondrodysplasias are caused by abnormal development and growth of cartilage and bone. These abnormalities have been reported in both humans and animals with dwarfism. The basset hound is considered a breed with a disproportionate prevalence of dwarfism, the cause of which is unknown. To determine the type of osteochondrodysplasia in this breed, we analyzed histologically the growth plates from the long bones of a basset hound and a Doberman pinscher, both 2 mo old. Tissue was fixed in 4% paraformaldehyde, embedded in paraffin, sectioned at 5 microm, stained with hematoxylin and eosin, and analyzed by light microscopy. Our results suggest that by this method the basset hound can be defined only as a breed having osteochondrodysplasia due to a primary cartilage problem in the growth plate.

Asphyxiating thoracic dystrophy with facial dysmorphism

Here it is reported a male newborn baby with features of asphyxiating thoracic dystrophy (ATD) with facial dysmorphism. The disproportionate rhizomelic short stature, narrow thorax, long fibulae, wide metaphysis and trident acetabule are consistent with diagnosis of ATD. In addition the baby had facial dysmorphism and broad thumbs and great toes similar to Oto-palato-digital syndrome type II (OPD II). The association of these features with ATD is not reported till date.

Rough endoplasmic reticulum abnormalities in a patient with spondyloepimetaphyseal dysplasia with scoliosis, joint laxity, and finger deformities

Iliac crest growth cartilage biopsy in spondyloepimetaphyseal dysplasia (SEMD) showed an endoplasmic reticulum storage disorder of epiphyseal and physeal chondrocytes. Biochemical analyses of iliac crest cartilage extracellular matrix showed no signs of deficits in any of the structural collagens types II, IX, or XI. The physis was abnormal by light microscopy with chondrocyte columnation replaced by clone-like cell accumulations surrounded by widened acellular cartilage septae. The rough endoplasmic reticulum (RER) of most chondrocytes was dilated. In some cells the RER contained homogeneous material but in most there were abnormal electron-dense accumulations. In some the material was seen in small amounts adjacent to the edge of the RER. In others, increasingly large amounts were seen that were randomly oriented and diffusely marginated. In many cells, assembly had progressed to well-marginated collections of wavy rod-like structures with a circular orientation parallel to the outer edges of the RER. The electron-dense accumulations measured from 34 to 40 nm in diameter. Mutations have prevented normal processing of collagen such that exit from the RER is abnormally slowed and abnormal self-assembly occurs within the dilated cisternae.

A novel compound heterozygous mutation in the DAP12 gene in a patient with Nasu-Hakola disease

A 34-year-old woman showed clinical features characteristic of Nasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL). The genetic analysis of the DAP12 gene (TYROBP) identified two heterozygous mutations composed of a previously reported single base deletion of 141G (141delG) in exon 3 and a novel single base substitution of G262T in exon 4, both of which are located on separate alleles. The protein sequence motif search indicated that both mutations encode truncated nonfunctional DAP12 polypeptides. This is the first case of NHD caused by compound heterozygosity for loss-of-function mutations in DAP12.

Compound heterozygous mutations of the SBDS gene in a patient with Shwachman-Diamond syndrome, type 1 diabetes mellitus and osteoporosis

Shwachman-Diamond syndrome (SDS) is characterized by exocrine pancreatic insufficiency, skeletal abnormalities and hematological dysfunction. The genetic analysis of the SBDS gene and the long-term follow-up of a 37-year-old man with SDS, osteoporosis and type 1 diabetes are reported. Analysis of the SBDS gene revealed a compound heterozygous genotype with 7 mutations. This genotype is the result of the inheritance of abnormal alleles from both healthy parents. We identified putatively non-functional gene conversions from the SBDS pseudogene into the otherwise normal SBDS gene in each of the parentally inherited alleles. The association of SDS and type 1 diabetes mellitus seems to be coincidental and not associated to distinct mutations of the SBDS gene. Osteoporosis in patients with SDS may be the result of a primary defect of the bone metabolism and not of a nutritional problem, although our patient had chronic hypophosphatemia. The long-term follow-up of this patient provides interesting insights into the course of SDS, showing the complexity of genotype-phenotype correlations and the possible influence of other modifying genes and/or environmental factors that might determine the phenotypic presentation of SDS in an individual patient.

Tracheobronchopathia osteochondroplastica occurring in a subsegmental bronchus and causing obstructive pneumonia

A 59-year-old man was referred to the University of Occupational and Environmental Health hospital because a chest roentgenogram obtained at an annual medical examination showed an abnormal shadow. We treated the patient for tracheobronchopathia osteochondroplastica, which caused segmental obstructive pneumonia that proved to be difficult to accurately diagnose before surgery.

A form of autosomal dominant spondyloepiphyseal dysplasia is caused by a glycine to alanine substitution in the COL2A1 gene

We report a family with an unusual form of autosomal dominant spondyloepiphyseal dysplasia characterized by infantile-onset disproportionate short stature with relative shortening of the spine, thoracic kyphosis, lumbar lordosis, scoliosis and premature osteoarthritis of the joints especially of the hips. Radiological findings include mild platyspondyly, vertebral end plate irregularity, irregular femoral necks, and dysplasia of the capital femoral epiphyses with flattening and irregularity present from childhood and mild variable epiphyseal dysplasia elsewhere in the skeleton. Intrafamilial variability is observed in the degree of short stature, severity of spinal and hip involvement and the age of onset of symptoms and complications. We demonstrate that this dysplasia is due to a glycine to alanine substitution in the COL2A1 gene (p.Gly862Ala), thereby expanding the phenotypic spectrum of dysplasias associated with defects in type II collagen.

CRTAP Is Required for Prolyl 3- Hydroxylation and Mutations Cause Recessive Osteogenesis Imperfecta

Prolyl hydroxylation is a critical posttranslational modification that affects structure, function, and turnover of target proteins. Prolyl 3-hydroxylation occurs at only one position in the triple-helical domain of fibrillar collagen chains, and its biological significance is unknown. CRTAP shares homology with a family of putative prolyl 3-hydroxylases (P3Hs), but it does not contain their common dioxygenase domain. Loss of Crtap in mice causes an osteochondrodysplasia characterized by severe osteoporosis and decreased osteoid production. CRTAP can form a complex with P3H1 and cyclophilin B (CYPB), and Crtap-/- bone and cartilage collagens show decreased prolyl 3-hydroxylation. Moreover, mutant collagen shows evidence of overmodification, and collagen fibrils in mutant skin have increased diameter consistent with altered fibrillogenesis. In humans, CRTAP mutations are associated with the clinical spectrum of recessive osteogenesis imperfecta, including the type II and VII forms. Hence, dysregulation of prolyl 3-hydroxylation is a mechanism for connective tissue disease.

Frontometaphyseal dysplasia: mutations in FLNA and phenotypic diversity

Frontometaphyseal dysplasia is an X-linked trait primarily characterized by a skeletal dysplasia comprising hyperostosis of the skull and modeling anomalies of the tubular bones. Extraskeletal features include tracheobronchial, cardiac, and urological malformations. A proportion of individuals have missense mutations or small deletions in the X-linked gene, FLNA. We report here our experience with comprehensive screening of the FLNA gene in a group of 23 unrelated probands (11 familial instances, 12 simplex cases; total affected individuals 32) with FMD. We found missense mutations leading to substitutions in the actin-binding domain and within filamin repeats 9, 10, 14, 16, 22, and 23 of filamin A in 13/23 (57%) of individuals in this cohort. Some mutations present with a male phenotype that is characterized by a severe skeletal dysplasia, cardiac, and genitourinary malformations that leads to perinatal death. Although no phenotypic feature consistently discriminates between females with FMD who are heterozygous for FLNA mutations and those in whom no FLNA mutation can be identified, there is a difference in the degree of skewing of X-inactivation between these two groups. This observation suggests that locus heterogeneity may exist for this disorder.

Anaplastic ependymoma with cartilaginous and osseous metaplasia: report of a rare case and review of literature

Gliomas with cartilaginous metaplasia are extremely uncommon and thought to be due to metaplasia of the mesenchymal supportive elements. The tumors are located in the midline, mostly fourth ventricle and rarely in the pons. The present paper describes an unusual case of anaplastic ependymoma with cartilaginous and osseous metaplasia in a young boy which was located in the suprasellar, interpeduncular prepontine and left cerebello-pontine cistern. To the best of our knowledge, this cartilaginous metaplasia in ependymomas has been reported only thrice.

Otopalatodigital syndrome spectrum disorders: otopalatodigital syndrome types 1 and 2, frontometaphyseal dysplasia and Melnick-Needles syndrome

The term otopalatodigital syndrome spectrum disorders is an umbrella category that includes four phenotypically related conditions, otopalatodigital syndrome types 1 and 2, frontometaphyseal dysplasia and Melnick - Needles syndrome. The phenotype of these conditions in the male ranges from a severe perinatally lethal multiple malformation syndrome to a mild skeletal dysplasia. Most, but not all, instances of these conditions are associated by mutations in the X-linked gene encoding the cytoskeletal protein filamin A. Mutations in this gene are clustered, exhibit a strong genotype-phenotype correlation and are presumed to exert their effect by a gain-of-function mechanism.

Novel FGFR3 mutations creating cysteine residues in the extracellular domain of the receptor cause achondroplasia or severe forms of hypochondroplasia

Achondroplasia (ACH) and hypochondroplasia (HCH) are two autosomal-dominant skeletal disorders caused by recurrent missense FGFR3 mutations in the transmembrane (TM) and tyrosine kinase 1 (TK1) domains of the receptor. Although 98% of ACH cases are accounted for by a single G380R substitution in the TM, a common mutation (N540K) in the TK1 region is detected in only 60-65% of HCH cases. The aim of this study was to determine whether the frequency of mutations in patients with HCH was the result of incomplete mutation screening or genetic heterogeneity. Eighteen exons of the FGFR3 gene were entirely sequenced in a cohort of 25 HCH and one ACH patients in whom common mutations had been excluded. Seven novel missense FGFR3 mutations were identified, one causing ACH and six resulting in HCH. Six of these substitutions were located in the extracellular region and four of them creating additional cysteine residues, were associated with severe phenotypes. No mutations were detected in 19 clinically diagnosed HCH patients. Our results demonstrate that the spectrum of FGFR3 mutations causing short-limb dwarfism is wider than originally recognised and emphasise the requirement for complete screening of the FGFR3 gene if appropriate genetic counselling is to be offered to patients with HCH or ACH lacking the most common mutations and their families.

Metaphyseal dysplasia of Braun-Tinschert type: report of a Japanese girl

We report on a 7-year-old Japanese girl with metaphyseal dysplasia (MD) of Braun-Tinschert type, a recently recognized, autosomal dominant sclerosing bone dysplasia. All individuals with the disorder from four families in the literature originated from a small town in Bohemia or its vicinity. The occurrence of the disorder in a Japanese girl indicates that it is not restricted to Germans. The radiographic hallmarks of the disorder include metaphyseal undermodeling (Erlenmeyer-flask deformity); osteosclerosis of the chondroosseous junctions, metaphyseal cortices, and epiphyseal margins; and exostosis-like bone excrescences at the metaphyseal-diaphyseal junctions. In the girl we described, the latter two findings were conspicuous at age 4 years, but became less prominent with increasing age. The metaphyseal trabeculae were somewhat coarse. The humeri exhibited varus deformity, and the ulnae and fibulae mild bowing. The mean bone mineral density of the lumbar spine was lower than that of age-matched controls. The patient exhibited premature loss of primary teeth, likely to be a sign of increased periodontal bone resorption. Markers of bone formation and resorption were both increased, an indication of a high rate of bone turnover.

Oto-spondylo-megaepiphyseal dysplasia (OSMED): clinical and radiological findings in sibs homozygous for premature stop codon mutation in the COL11A2 gene

Oto-spondylo-megaepiphyseal dysplasia (OSMED) is a very rare disorder due to mutation of type XI collagen. Less than 30 patients have been reported in the literature so far. It could be either of autosomal dominant (OMIM 154780) or recessive (OMIM 215150) etiology. Two sibs with OSMED are presented. They had disproportionate short stature and short limbs, distinct face with midface hypoplasia, short nose, depressed nasal bridge, long philtrum, and non-progressive sensorineural deafness. Radiological findings showed short long bones and large epiphyses with metaphyseal flaring and mild platyspondyly and coronal clefting. Homozygosity of a single nucleotide deletion in exon 55 causing a premature stop codon in exon 56 of COL11A2 was detected in the affected sibs. Parents were heterozygotes for the same mutation and interestingly, the father had mild unilateral non-progressive sensorineural deafness. This finding adds more weight that the type of mutation and location in COL11A2 are crucial in determining the phenotype. The purpose of this study is to report clinical and radiological findings in two molecularly proven Egyptian sibs with autosomal recessive OSMED.