International classification of osteochondrodysplasias

Nosology of genetic skeletal disorders: 2023 revision

The "Nosology of genetic skeletal disorders" has undergone its 11th revision and now contains 771 entries associated with 552 genes reflecting advances in molecular delineation of new disorders thanks to advances in DNA sequencing technology. The most significant change as compared to previous versions is the adoption of the dyadic naming system, systematically associating a phenotypic entity with the gene it arises from. We consider this a significant step forward as dyadic naming is more informative and less prone to errors than the traditional use of list numberings and eponyms. Despite the adoption of dyadic naming, efforts have been made to maintain strong ties to the MIM catalog and its historical data. As with the previous versions, the list of disorders and genes in the Nosology may be useful in considering the differential diagnosis in the clinic, directing bioinformatic analysis of next-generation sequencing results, and providing a basis for novel advances in biology and medicine.

Cardiac Defects and Genetic Syndromes: Old Uncertainties and New Insights

Recent advances in understanding the genetic causes and anatomic subtypes of cardiac defects have revealed new links between genetic etiology, pathogenetic mechanisms and cardiac phenotypes. Although the same genetic background can result in different cardiac phenotypes, and similar phenotypes can be caused by different genetic causes, researchers’ effort to identify specific genotype–phenotype correlations remains crucial. In this review, we report on recent advances in the cardiac pathogenesis of three genetic diseases: Down syndrome, del22q11.2 deletion syndrome and Ellis–Van Creveld syndrome. In these conditions, the frequent and specific association with congenital heart defects and the recent characterization of the underlying molecular events contributing to pathogenesis provide significant examples of genotype–phenotype correlations. Defining these correlations is expected to improve diagnosis and patient stratification, and it has relevant implications for patient management and potential therapeutic options.

Rickets manifestations in a child with metaphyseal anadysplasia, report of a spontaneously resolving case

Introduction

Rickets is not an unusual diagnosis for pediatricians even currently in developed countries. Children typically present with leg bowing, enlargement of wrists, rachitic rosary (swelling of costochondral junctions) and/or waddling gait. But not every child with growth delay and enlarged metaphyses is diagnosed with rickets. Metaphyseal anadysplasia (MAD) is a disorder of variable severity with metaphyseal flaring and irregularities, without vertebral abnormalities. MAD is characterized by an early onset and a regressive course in late childhood without treatment, despite persistent short stature. Autosomal dominant or recessive variants in the matrix metalloproteinase 13 gene (MMP13) are responsible for these transient metaphyseal changes.

Case presentation

We report a new pathogenic heterozygous variant in MMP13 (NM_002427.4: c.216G>C, p.Gln72His) in a toddler, initially thought to have rickets, and his father, with MAD phenotypes. Additionally, we review the seven reported MMP13 variants.

Conclusion

One should keep a wide differential diagnosis in cases of suspected rickets, including skeletal dysplasias which might have a regressive course.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02716-x.

The evolution of the nosology of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a relatively common genetic skeletal disorder with an estimated frequency of 1 in 20 000 worldwide. The manifestations are diverse and although individually rare, the several different forms contribute to the production of a significant number of affected individuals with considerable morbidity and mortality. During the last decade, there have been extensive molecular investigations into the etiology of OI and these advances have direct relevance to the medical management of the disorder, and the purpose of this review is to document the history and evolution of the nosology of OI. The current nosology, based on molecular concepts, which are crucial in the identification of genotype-phenotype correlations in persons with OI, is also outlined. The successive revisions of the nosology and classification of OI have highlighted the importance of the nomenclature of the condition in order for it to be recognized by clinicians, scientists and patient advocacy groups. In this way, improved counseling of patients and individualized, tailored therapeutic approaches based on the underlying pathophysiology of the individual's type of OI have been facilitated.

Nosology and classification of genetic skeletal disorders: 2019 revision

The application of massively parallel sequencing technology to the field of skeletal disorders has boosted the discovery of the underlying genetic defect for many of these diseases. It has also resulted in the delineation of new clinical entities and the identification of genes and pathways that had not previously been associated with skeletal disorders. These rapid advances have prompted the Nosology Committee of the International Skeletal Dysplasia Society to revise and update the last (2015) version of the Nosology and Classification of Genetic Skeletal Disorders. This newest and tenth version of the Nosology comprises 461 different diseases that are classified into 42 groups based on their clinical, radiographic, and/or molecular phenotypes. Remarkably, pathogenic variants affecting 437 different genes have been found in 425/461 (92%) of these disorders. By providing a reference list of recognized entities and their causal genes, the Nosology should help clinicians achieve accurate diagnoses for their patients and help scientists advance research in skeletal biology.

Overlapping genetic pathways in the skeletal dysplasias of a middle woodland individual: A case study

Studies of interacting/overlapping genetic skeletal disorders are rare for populations today, but even more so for archaeological contexts. The skeletal remains of an adult female (EZ 3-7-1) were excavated in the 1980s from the Middle Woodland (50BC-AD400) context of the Elizabeth site (11PK512) in the lower Illinois Valley (LIV), USA. Reported here are the standard score (z-score) comparisons of the measured skeletal differences of EZ 3-7-1 with a reference sample and a re-analysis of the individual's pathological changes, with special consideration placed on refining the disease diagnosis. The impressive preservation and meticulous recovery of these skeletal remains have provided the opportunity to identify the first and earliest archaeological example of an individual (EZ 3-7-1) with a combined genetic skeletal dysplasia, Leri-Weill dyschondrosteosis and achondroplasia.

Prenatal diagnosis of Jeune-like syndromes with two-dimensional and three-dimensional sonography

The purpose of this article is to describe the use of three-dimensional sonography as an adjuvant to two-dimensional sonography facilitating an earlier and more definitive diagnosis of Jeune and Jeune-like syndromes in the second trimester. We report two cases in which three-dimensional sonography facilitated the diagnosis of these malformations. A diagnosis of Jeune syndrome was made in our first case. Our second case was found to be short-rib polydactyly syndrome Type IV. Three-dimensional skeletal survey visualized short ribs, short limbs, the presence of normal scapulae, and the absence of polydactyly in both cases. Three-dimensional sonography can assist two-dimensional sonography in providing a more accurate display of skeletal anomalies, limb abnormalities, and facial features.

[Implications of the new etiophatogenic approach in the classification of constitutional and genetic bone diseases]

Recent years have seen an unprecedented increase in the knowledge and understanding of biochemical disturbances involved on constitutional bone disorders. Recognition of the genetic background as the common cause of these diseases prompted the substitution of the term «constitutional» by «genetic», in referring to them. Understanding physiopathological bases by finding out the altered metabolic pathways as well as their regulatory and control systems, favours an earlier and more accurate diagnosis based on interdisciplinary collaboration. Although clinical and radiological assessment remains crucial in the study of these disorders, ever more often the diagnosis is achieved by molecular and genetic analysis. Elucidation of the damaged underlying molecular mechanisms offers targets potentially useful for therapeutic research in these complex and often disabling diseases.

Cartilage oligomeric matrix protein deficiency promotes early onset and the chronic development of collagen-induced arthritis

Introduction

Cartilage oligomeric matrix protein (COMP) is a homopentameric protein in cartilage. The development of arthritis, like collagen-induced arthritis (CIA), involves cartilage as a target tissue. We have investigated the development of CIA in COMP-deficient mice.

Methods

COMP-deficient mice in the 129/Sv background were backcrossed for 10 generations against B10.Q mice, which are susceptible to chronic CIA. COMP-deficient and wild-type mice were tested for onset, incidence, and severity of arthritis in both the collagen and collagen antibody-induced arthritis models. Serum anti-collagen II and anti-COMP antibodies as well as serum COMP levels in arthritic and wild-type mice were measured by enzyme-linked immunosorbent assay.

Results

COMP-deficient mice showed a significant early onset and increase in the severity of CIA in the chronic phase, whereas collagen II-antibody titers were similar in COMP-deficient and wild-type controls. COMP antibodies were not found in wild-type mice. Finally, COMP-deficient and wild-type mice responded similarly to collagen antibody-induced arthritis, indicating no difference in how collagen II antibodies interact with COMP-deficient cartilage during the initial stages of arthritis.

Conclusions

COMP deficiency enhances the early onset and development of chronic arthritis but does not affect collagen II autoimmunity. These findings accentuate the importance of COMP in cartilage stability.

Genetic analysis of skeletal dysplasia: recent advances and perspectives in the post-genome-sequence era

Skeletal dysplasia is a group of disorders of the skeleton that result from derangement of growth, development and/or differentiation of the skeleton. Nearly 300 disorders are included; most of them are monogenic diseases. Responsible genes for skeletal dysplasia have been identified in more than 150 diseases mainly through positional cloning. Identification of disease genes would improve patient care through genetic diagnosis as well as improving our understanding of the diseases and molecular mechanism of skeletal tissue formation. Studies of skeletal dysplasia would also help identify disease genes for common diseases affecting bones and joints. In this study, the author reviews recent advances and the current status of the genetic analysis of skeletal dysplasia and its impacts on research into skeletal biology.

Mutation (D472Y) in the type 3 repeat domain of cartilage oligomeric matrix protein affects its early vesicle trafficking in endoplasmic reticulum and induces apoptosis

Cartilage oligomeric matrix protein (COMP) is a large pentameric extracellular glycoprotein found in cartilage, tendon, and synovium, and plays structural roles in cartilage as the fifth member of the thrombospondin family. Familial mutations in type 3 repeats of COMP are known to cause pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (EDM1). Although such mutations induce enlarged rough endoplasmic reticulum (rER) as a morphological change, the metabolic trafficking of mutated COMP remains unclear. In transfected COS7 cells, wild-type COMP was rapidly secreted into culture medium, while the great majority of COMP with the type 3 repeats mutation (D472Y) remained in the cells and a small portion of mutated COMP was secreted. This finding was followed up with a confocal study with an antibody specific to COMP, which demonstrated mutated COMP tightly associated with abnormally enlarged rER. Phosphorylated eIF2alpha, an ER stress protein, was expressed as a pathological reaction in virtually all COS7 cells expressing mutated but not wild-type COMP. Moreover, COS7 cells expressing mutated COMP exhibited significantly more apoptotic reaction than those expressing wild-type COMP. Pathological accumulation of COMP in rER and apoptosis in COS7 cells that were induced by the mutation (D472Y) in COMP imply that COMP mutations play a role in the pathogenesis of PSACH.

Craniometaphyseal dysplasia: a case report and review of medical and surgical management

Craniometaphyseal dysplasia (CMD) is a genetic syndrome involving cranial and tubular bone anomalies that commonly present at a young age, often with otolaryngologic manifestations. In this paper, we report a rare case of a sporadic form of the disease resulting in an early state of hypocalcemia with secondary hyperparathyroidism. A conductive hearing loss is also documented prior to 12 months of age. The clinical aspects of CMD will be covered along with its pathogenesis. The current concepts surrounding medical and surgical treatments will be reviewed, and the management of our patient will be discussed.

Craniometaphyseal dysplasia: a case report and review of medical and surgical management

Craniometaphyseal dysplasia (CMD) is a genetic syndrome involving cranial and tubular bone anomalies that commonly present at a young age, often with otolaryngologic manifestations. In this paper, we report a rare case of a sporadic form of the disease resulting in an early state of hypocalcemia with secondary hyperparathyroidism. A conductive hearing loss is also documented prior to 12 months of age. The clinical aspects of CMD will be covered along with its pathogenesis. The current concepts surrounding medical and surgical treatments will be reviewed, and the management of our patient will be discussed.

Fetal fibrochondrogenesis at 26 weeks' gestation

Fibrochondrogenesis is a rare and lethal osteochondrodysplasia with an autosomal recessive mode of inheritance. We report a male fetus in which the diagnosis of lethal osteochondrodysplasia was suspected on prenatal ultrasound and radiological examinations during the second trimester of pregnancy. After termination of pregnancy, fibrochondrogenesis was diagnosed by radiological examination and histological study of fetal bones. Interwoven fibrous septa and fibroblastic degeneration of chondrocytes are pathognomonic. The recurrence rate is 25% and accurate diagnosis is necessary to enable genetic counselling.

Cartilage oligomeric matrix protein-deficient mice have normal skeletal development

Cartilage oligomeric matrix protein (COMP) belongs to the thrombospondin family and is a homopentamer primarily expressed in cartilage. Mutations in the COMP gene result in the autosomal dominant chondrodysplasias pseudoachondroplasia (PSACH) and some types of multiple epiphyseal dysplasia (MED), which are characterized by mild to severe short-limb dwarfism and early-onset osteoarthritis. We have generated COMP-null mice to study the role of COMP in vivo. These mice show no anatomical, histological, or ultrastructural abnormalities and show none of the clinical signs of PSACH or MED. Northern blot analysis and immunohistochemical analysis of cartilage indicate that the lack of COMP is not compensated for by any other member of the thrombospondin family. The results also show that the phenotype in PSACH/MED cartilage disorders is not caused by the reduced amount of COMP.

Early prenatal sonographic diagnosis and follow-up of Jeune syndrome

Jeune syndrome or asphyxiating thoracic dysplasia is an autosomal recessive osteochondrodysplasia. It is one of the six short-rib (polydactyly) syndromes. The disease has a wide spectrum of manifestations, ranging from a latent to a mild or lethal condition. We describe the prenatal sonographic diagnosis of Jeune syndrome at 14 weeks of gestation in a fetus at risk for this condition, and the development of the syndrome throughout the pregnancy.

Present status of the use of growth hormone in short children with bone diseases (diseases of the skeleton)

Skeletal dysplasias are genetic disorders of bone and cartilage development, mainly characterized by disproportionate short stature. Achondroplasia is the commonest and best described form of skeletal dysplasia, leading to a mean final height of 131+/-5.6 cm for males and 124+/-5.9 cm for females. Growth hormone (GH) has been used in different studies in patients with achondroplasia in order to ameliorate their height, and short term results range from rather positive to moderate. However, disproportionate advancement of bone age has been observed that can compromise the positive effect of such treatment. Furthermore, concern exists about the aggravation of body disproportion necessitating a later leg lengthening procedure in order to achieve proportionate adult stature. In hypochondroplasia, GH treatment seems to give better results when administered at puberty. No data on final height yet exist, however, so that more studies with greater numbers of patients need to be performed before a consensus on GH use in achondroplasia and hypochondroplasia can be reached. Other forms of skeletal dysplasias are quite rare, so that no conclusion on GH use in such patients can be drawn. Finally, in osteogenesis imperfecta, GH administration significantly ameliorates bone density but does not clearly seem to affect final height positively.

The genetic basis of the osteochondrodysplasias

The osteochondrodysplasias are a heterogeneous group of disorders characterized by abnormal growth and remodeling of cartilage and bone, affecting from 2 to 4.7 per 10,000 individuals. Most osteochondrodysplasias are heritable and many have elaborate patterns of genetic transmission. Affected individuals generally require management by multidisciplinary teams of specialists. In this review, we divide the osteochondrodysplasias into groups based on their genetic relationships, including mutations in various types of collagen, fibroblast growth factor, cartilage oligomeric matrix protein, parathyroid hormone receptor, the diastrophic dysplasia sulfate transporter, enzymes such as steroid sulfatases, transcription factor SOX9, and a cysteine proteinase, cathepsin K. We describe the major osteochondrodysplasias, define their causes and clinical manifestations, and provide the orthopaedic surgeon with an understanding of the underlying molecular defects as well as the anatomical aspects of these disorders.

Prenatal sonographic diagnosis of skeletal dysplasias. A report of 47 cases

The purpose of this study was to evaluate the foetal sonographic efficiency for prenatal diagnosis of osteochondrodysplasias. Forty-seven prenatal and postnatal cases diagnosed between January 1993 and December 1998 in the referral sonographic centres of Strasbourg were studied. All cases were reviewed retrospectively and the prenatal ultrasound findings and diagnosis were compared to the postnatal or post-mortem diagnosis. Each case was studied by ultrasonographers, geneticists, radiologists, and foetopathologists. Final diagnosis was based on clinical examination, skeletal survey and molecular testing as deemed necessary. Routine screening and dating was the indication for foetal sonography in 72% (32/47) of our cases. The most likely time of diagnosis was between 16 and 24 weeks of gestation (17 out of 47 cases, 36%), which corresponds to the time of foetal anomaly sonographic scan in France. The other cluster of cases (12 among 47, 26%) was disclosed before 16 weeks of gestation. These results illustrate the importance of a detailed evaluation of the limbs during sonographic examinations of first and second trimesters of pregnancy. While the identification of skeletal dysplasias was relatively easy in our study, the ability to make an accurate specific antenatal diagnosis was more difficult. An accurate diagnosis was proposed in 28 of the 47 cases (60%). In 19% of the cases (9/47), the prenatal diagnosis was not accurate; in 21% of the cases (10/47), the prenatal diagnosis was imprecise. In 45 of the 47 cases (96%) prenatal foetal scan correctly predicted the prognosis.

Molecular cloning and expression patterns of mouse cartilage oligomeric matrix protein gene

OBJECTIVE

To develop transgenic mice harboring mutations in the COMP gene as animal models for pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), autosomal dominant disorders characterized by early onset osteoarthritis and epiphyseal abnormalities. As a first step in generating a mouse model for COMP mutations, we have cloned the cDNA of mouse COMP and examined its tissue expression pattern.

DESIGN

Total mRNA was isolated from the skeletal tissues of newborn C57BL/6j mice and used as a template for oligo(dT) first-strand cDNA synthesis. The cDNA was used for PCR amplification of COMP using three oligonucleotide primer pairs designed from the published rat COMP cDNA sequence. Nested PCR was used to complete the sequence between the amplified fragments. The entire cDNA was sequenced and the expression pattern of the corresponding transcripts examined by Northern hybridizations.

RESULTS

A full-length COMP cDNA was isolated. Analysis showed that the entire translated region of the mouse COMP gene is 2268 bp and the derived amino acid sequence shows 90% homology to human COMP. Of eight adult mouse non-cartilage tissues tested, COMP expression was detected only in testis.

Cervical spine disorders in children

Care of children with disorders of the cervical spine requires an understanding of the anatomic and biologic features particular to the developing pediatric spine. Congenital and developmental alterations further complicate evaluation and treatment of children. Basic knowledge of pediatric cervical spine disorders in Down syndrome, Klippel-Feil syndrome, osteochondrodysplasias, mucopolysaccharidoses, and post-traumatic instability is essential for all orthopedic surgeons. Thorough patient evaluation and appropriate early management may prevent potentially serious neurologic injury and other complications related to cervical spine pathology.

Cardiac malformations in patients with oral-facial-skeletal syndromes: clinical similarities with heterotaxia

Oral-facial-skeletal (OFS) syndromes include short rib-polydactyly (SRP) and oral-facial-digital (OFD) syndromes. Congenital heart defect (CHD), mainly atrioventricular canal defect (AVCD), is a cardinal finding in the Ellis-van Creveld (EVC) syndrome, but it occurs only occasionally in other SRP and OFD syndromes. The cardiac characteristics of all patients with OFS syndromes evaluated at our hospital from January 1986 to April 1997 were analyzed and compared with published reports. Ten patients with EVC syndrome, one with McKusick-Kaufman syndrome, and one with OFD syndrome type II had AVCD. Eight patients (67%) had a common atrium, eight (67%) a persistent left superior vena cava (LSVC) draining into the left atrium because of an unroofed coronary sinus in five (42%), and left-sided obstructive lesions in three (25%). One patient with EVC syndrome had AVCD, common atrium, double outlet right ventricle, persistent LSVC associated with "asplenia syndrome," visceral heterotaxia, and right isomerism. The combination of CHDs found in the personal series of OFS syndromes suggests pathogenetic similarity with heterotaxia syndromes. Published results also corroborate the association between OFS syndromes and CHDs usually occurring in heterotaxia. Molecular studies could shed light on the genetic mechanisms implicated in the cause of the OFS and heterotaxia syndromes.

Clinical, genetical, radiological, and anatomopathological survey of 17 patients with lethal osteochondrodysplasias

Seventeen patients thought to have lethal osteochondrodysplasias were evaluated. Diagnosis was established through clinical evaluation, radiological studies and necropsy. Genetic counseling was provided to the affected patient's families. Specific diagnosis was confirmed in 16 cases. Nosologic diagnosis was done through clinical evaluation. However, the most efficient method for verifying the diagnosis was a skeletal radiological study. This fact corroborates the orientation of the International Classification of Osteochondrodysplasias (International Working Group on Constitutional Disease of Bone, 1992) in which a radiological criterion was adopted as the most relevant for classification of osteochondrodysplasias. An anatomopathological study was also done to detect internal anomalies, and was effective in identifying abnormalities in epiphyseal growth plate in a bone fragment study. This method had low specificity, but in two cases it was especially decisive for diagnostic differentiation.

Diverse mutations in the gene for cartilage oligomeric matrix protein in the pseudoachondroplasia-multiple epiphyseal dysplasia disease spectrum

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are autosomal dominant osteochondrodysplasias that result in mild to severe short-limb dwarfism and early-onset osteoarthrosis. PSACH and some forms of MED result from mutations in the gene for cartilage oligomeric matrix protein (COMP; OMIM 600310 [http://www3.ncbi.nlm. nih.gov:80/htbin-post/Omim/dispmim?600310]). We report the identification of COMP mutations in an additional 14 families with PSACH or MED phenotypes. Mutations predicted to result in single-amino acid deletions or substitutions, all in the region of the COMP gene encoding the calmodulin-like repeat elements, were identified in patients with moderate to severe PSACH. We also identified within this domain a missense mutation that produced MED Fairbank. In two families, one with mild PSACH and the second with a form of MED, we identified different substitutions for a residue in the carboxyl-terminal globular region of COMP. Both the clinical presentations of these two families and the identification of COMP-gene mutations provide evidence of phenotypic overlap between PSACH and MED. These data also reveal a role for the carboxyl-terminal domain in the structure and/or function of COMP.

Progressive pseudorheumatoid dysplasia: report of a family and review

Progressive pseudorheumatoid dysplasia is an inherited skeletal dysplasia with radiographic changes notably in the spine, similar to spondyloepiphyseal dysplasia tarda. There is also articular cartilage involvement which gives it some clinical resemblance to rheumatoid arthritis. We report here on six subjects from one inbred family from Jordan. Based on previously published reports and this one, we review the clinical and radiological features and discuss the genetics and differential diagnosis of the disorder. We suggest the addition of the word "spondyloepiphyseal" to the name adopted by the International Working Group on Constitutional Diseases of Bone, to become "progressive pseudorheumatoid spondyloepiphyseal dysplasia". We also speculate on candidate genes for this disorder.

Is management of anesthesia in achondroplastic dwarfs really a challenge?

STUDY OBJECTIVE

To review our eight-year anesthetic experience with achondroplastic patients.

DESIGN

Retrospective study.

SETTING

University hospital.

PATIENTS

15 achondroplastic patients who underwent 53 surgical procedures of orthopedic surgery between 1987 and 1994.

INTERVENTIONS

Anesthetic technique, drugs, number of incidents, and complications in the intraoperative and postoperative period were recorded.

MEASUREMENTS AND MAIN RESULTS

Adequate premedication before the transfer to the operating room was very useful to reduce anxiety and increase cooperation. Inhalation induction was well tolerated and allowed easy peripheral venous cannulation. Only one patient presented difficulties during intubation (on two occasions). In the other patients, we found small difficulties only during ventilation with a face mask, which was easily corrected by modifying the position of the patient and/or inserting an oropharyngeal airway. No adverse effect was identified for any particular anesthetic drug or technique used.

CONCLUSIONS

Although the characteristic deformities of achondroplastic patients can impede the management of anesthesia, in our study we found no special difficulties. Airway complications did not occur. Thus, no specific optimal anesthetic regimen can be recommended.

Short rib-polydactyly syndrome in twins: Beemer-Langer type with polydactyly

We present premature female twin fetuses with concordant extremely shortened ribs, short limbs, macrocephaly, median cleft upper lip and facial dysmorphism. Based on radiological criteria and the pattern of associated abnormalities, a lethal short rib-polydactyly syndrome (Beemer-Langer type) was diagnosed. The differential diagnosis of this entity is discussed.

Jeune syndrome with tongue lobulation and preaxial polydactyly, and Jeune syndrome with situs inversus and asplenia: compound heterozygosity Jeune-Mohr and Jeune-Ivemark?

We report on a male infant with internal hydrocephalus, absence of corpus callosum, papillomas and lobulation of the tongue, notches of the alveolar ridges, short ribs, dysplastic pelvis, hypospadias, short limbs with bowed long tubular bones and postaxial polydactyly of hands, and preaxial polydactyly in one foot. Radiologically this case shares manifestations with Jeune syndrome; the tongue lobulation and the preaxial polydactyly are similar to findings in Mohr syndrome, or short-rib polydactyly syndrome (SRPS), type Majewski. In addition, a female newborn presented with manifestations of Jeune and Ivemark syndromes. One explanation for this overlap may be compound heterozygosity for these syndromes.

Achondrogenesis type II with polydactyly

We report on a newborn male infant who presented the typical findings of achondrogenesis type II (Langer-Saldino), and who also showed postaxial polydactyly on both feet and bilateral microtia. Polydactyly is frequently part of the short-rib syndromes, but has not been reported in achondrogenesis. The hypothesis of polydactyly as part of a contiguous gene syndrome is discussed.

Prenatal diagnosis of recurrence of short rib-polydactyly syndrome

We describe a nonconsanguineous couple whose 3 successive pregnancies, including one pair of twins, led to the birth of 4 infants with short rib-polydactyly syndrome (SRPS). Flat face, hypoplastic thorax, short limbs and ribs, polydactyly, absence of penis, and death after birth were noted in the first affected male baby. The affected female twins were detected prenatally by ultrasonography and had the same characteristics, but milder than the previous one. Serial measurements of the thoracic circumference and the 4 limbs were obtained by ultrasound, and showed progressively decreased ratio of thoracic to abdominal circumference and shortness of the limbs. The last male baby also had a similar but variable expression in prenatal ultrasonography.

De novo 17q paracentric inversion mosaicism in a patient with Beemer-Langer type short rib-polydactyly syndrome with special consideration to the classification of short rib polydactyly syndromes

A de novo 17q paracentric inversion mosaicism is detected in a fetus with type IV short rib (polydactyly) syndrome (Beemer-Langer). The cytogenetic finding in our case suggests a possible location of the gene or cluster of linked genes responsible for SR (P) S type IV to 17q21 or 17q23. Since this chromosome abnormality has not been described in short rib polydactyly syndromes and the existence of type IV SR (P) S has been controversial, the literature of this entity is reviewed with special consideration to the classification of short rib polydactyly syndromes.

Anthropometry in skeletal dysplasia

Skeletal dysplasia or osteochondrodysplasia is the designation of more than 200 different disorders, that are characterized by abnormalities of the skeleton, disproportional short stature, and a variety of other problems. The underlying biochemical defect is unknown in the vast majority of skeletal dysplasias, and the diagnosis is based on radiological findings and anthropometric measurements. Despite this fact, the information on body proportions in even the more common forms of skeletal dysplasia is scarce. Patients with achondroplasia are often diagnosed shortly after birth. Linear growth is severely compromised with relatively short extremities. Head circumference is above normal and final height ranges from 115 to 145 cm in males and 112 to 137 cm in females. Individuals with hypochondroplasia may go unnoticed until puberty, at which time the growth problem becomes obvious. Sitting height to height ratio is increased, but the body disproportion may not be apparent until puberty. Final height has been reported between 118 and 165 cm. Spondyloepiphyseal and spondylometaepiphyseal dysplasias are characterized by severe impairment of growth both in trunk and extremities, and therefore the sitting height to height ratio may be normal. Final height is severely reduced and ranges from 94 to 132 cm. It is concluded that anthropometric studies of patients with skeletal dysplasia are needed. More quantitative information on body proportions may assist in the diagnostic procedure and ensure that growth promoting therapy, e.g. growth hormone, does not worsen the disproportion.

A large family with features of pseudoachondroplasia and multiple epiphyseal dysplasia: exclusion of seven candidate gene loci that encode proteins of the cartilage extracellular matrix

We have identified a large family with a dominantly inherited chondrodysplasia characterized by a waddling gait, short limbs, and early onset osteoarthritis. The radiographic presentation resembles pseudoachondroplasia in childhood and multiple epiphyseal dysplasia in adults. Electron microscopic examination of cartilage reveals accumulation of material within the rough endoplasmic reticulum similar to that seen in pseudoachondroplasia and the Fairbank type of multiple epiphyseal dysplasia. By linkage analysis, we have excluded the genes for aggrecan, decorin, hexabrachion (tenascin), type II procollagen, the alpha 1 chain of type XI procollagen, the alpha 1 chain of type IX procollagen, and link protein, candidate genes that encode structural components of the cartilage extracellular matrix, as the disease locus for this disorder.

Lethal skeletal dysplasia from targeted disruption of the parathyroid hormone-related peptide gene

The parathyroid hormone-related peptide (PTHrP) gene was disrupted in murine embryonic stem cells by homologous recombination, and the null allele was introduced into the mouse germ line. Mice homozygous for the PTHrP null mutation died postnatally, probably from asphyxia, and exhibited widespread abnormalities of endochondral bone development. Histological examination revealed a diminution of chondrocyte proliferation, associated with premature maturation of chondrocytes and accelerated bone formation. Analysis of earlier developmental stages revealed that disturbance in cartilage growth preceded abnormal endochondral bone formation. There were no morphological abnormalities apparent in other tissues. These results provide direct evidence implicating PTHrP in normal skeletal development and serve to emphasize its potential involvement in human osteochondrodysplasias.

Early prenatal diagnosis of polycystic pancreas with narrow thorax and short limb dwarfism

We describe the ultrasound findings of polycystic pancreas with short rib dwarfism in the early second trimester. Radiologic, morphologic, and histologic examination after pregnancy termination confirmed the findings and also disclosed dysplastic kidneys. The skeletal anomalies are similar to those in Verma Naumoff type of short rib polydactyly, but the extraskeletal malformations have never been reported before in this syndrome.

Bone dysplasias of infancy in the Vienna collection

The Vienna Museum of Pathological Anatomy contains a vast collection of abnormal skeletons. We have appraised this material and attempted to establish firm diagnoses of specific genetic disorders in terms of modern syndromic concepts. A number of the skeletons in the museum are those of deceased neonates; in many instances it was impossible to reach a diagnosis on the basis of the outward appearance but radiographic investigations confirmed diagnoses including osteogenesis imperfecta type II, thanatophoric dysplasia, achondroplasia and achondrogenesis. The Vienna collection represents a priceless resource for the investigation of genetic skeletal disorders of this type.

Genetic linkage of mild pseudoachondroplasia (PSACH) to markers in the pericentromeric region of chromosome 19

Pseudoachondroplasia (PSACH) is a dominantly inherited form of short-limb dwarfism characterized by dysplastic changes in the spine, epiphyses, and metaphyses and early onset osteoarthropathy. Chondrocytes from affected individuals accumulate an unusual appearing material in the rough endoplasmic reticulum, which has led to the hypothesis that a structural abnormality in a cartilage-specific protein produces the phenotype. We recently identified a large family with a mild form of pseudoachondroplasia. By genetic linkage to a dinucleotide repeat polymorphic marker (D19S199), we have localized the disease gene to chromosome 19 (maximum lod score of 7.09 at a recombination fraction of 0.03). Analysis of additional markers and recombinants between the linked markers and the phenotype suggests that the disease gene resides within a 6.3-cM interval in the immediate pericentromeric region of the chromosome.

New findings in short rib syndrome

This white infant, born at 37 weeks of gestation, had a large cranium, bilateral anophthalmia, a midline cleft lip and palate, hypoplastic chest with short ribs, slightly protuberant abdomen, short limbs, bilateral single transverse palmar creases, a single umbilical artery, normal female external genitalia, normal (46 XY) chromosomes, and radiographic findings suggesting a short-rib (polydactyly) syndrome type IV (Beemer-Langer). Autopsy showed pulmonary hypoplasia, bilateral renal cystic dysplasia, intrahepatic bile duct cysts with periportal fibrosis, pancreatic cysts, absent internal genitalia, an atrophic optic chiasm, absent optic nerves, a single left anterior cerebral artery, polymicrogyria, and fusion of the frontal lobes, preoptic region, mammillary bodies, and thalami.