A lifespan approach to osteoarthritis prevention

Prevention is an attractive solution for the staggering and increasingly unmanageable burden of osteoarthritis. Despite this, the field of osteoarthritis prevention is relatively immature. To date, most of what is known about preventing osteoarthritis and risk factors for osteoarthritis is relative to the disease (underlying biology and pathophysiology) of osteoarthritis, with few studies considering risk factors for osteoarthritis illness, the force driving the personal, financial and societal burden. In this narrative review we will discuss what is known about osteoarthritis prevention, propose actionable prevention strategies related to obesity and joint injury which have emerged as important modifiable risk factors, identify where evidence is lacking, and give insight into what might be possible in terms of prevention by focussing on a lifespan approach to the illness of osteoarthritis, as opposed to a structural disease of the elderly. By targeting a non-specialist audience including scientists, clinicians, students, industry employees and others that are interested in osteoarthritis but who do not necessarily focus on osteoarthritis, the goal is to generate discourse and motivate inquiry which propel the field of osteoarthritis prevention into the mainstream.

Dysregulated BMP signaling through ACVR1 impairs digit joint development in fibrodysplasia ossificans progressiva (FOP)

The development of joints in the mammalian skeleton depends on the precise regulation of multiple interacting signaling pathways including the bone morphogenetic protein (BMP) pathway, a key regulator of joint development, digit patterning, skeletal growth, and chondrogenesis. Mutations in the BMP receptor ACVR1 cause the rare genetic disease fibrodysplasia ossificans progressiva (FOP) in which extensive and progressive extra-skeletal bone forms in soft connective tissues after birth. These mutations, which enhance BMP-pSmad1/5 pathway activity to induce ectopic bone, also affect skeletal development. FOP can be diagnosed at birth by symmetric, characteristic malformations of the great toes (first digits) that are associated with decreased joint mobility, shortened digit length, and absent, fused, and/or malformed phalanges. To elucidate the role of ACVR1-mediated BMP signaling in digit skeletal development, we used an Acvr1^R206H/+;Prrx1-Cre knock-in mouse model that mimics the first digit phenotype of human FOP. We have determined that the effects of increased Acvr1-mediated signaling by the Acvr1^R206H mutation are not limited to the first digit but alter BMP signaling, Gdf5+ joint progenitor cell localization, and joint development in a manner that differently affects individual digits during embryogenesis. The Acvr1^R206H mutation leads to delayed and disrupted joint specification and cleavage in the digits and alters the development of cartilage and endochondral ossification at sites of joint morphogenesis. These findings demonstrate an important role for ACVR1-mediated BMP signaling in the regulation of joint and skeletal formation, show a direct link between failure to restrict BMP signaling in the digit joint interzone and failure of joint cleavage at the presumptive interzone, and implicate impaired, digit-specific joint development as the proximal cause of digit malformation in FOP.

Exome reports A de novo GNB2 variant associated with global developmental delay, intellectual disability, and dysmorphic features

Heterotrimeric G proteins are composed of α, β, and γ subunits and are involved in integrating signals between receptors and effector proteins. The 5 human Gβ proteins (encoded by GNB1, GNB2, GNB3, GNB4, and GNB5) are highly similar. Variants in GNB1 were identified as a genetic cause of developmental delay. De novo variant in GNB2 has recently been reported as a cause of sinus node dysfunction and atrioventricular block but not as a cause of developmental delay. Trio-based whole-exome sequencing was performed on an individual with global developmental delay, muscle hypotonia, multiple congenital joint contractures and dysmorphism such as brachycephalus, thick eyebrows, thin upper lip, micrognathia, prominent chin, and bilateral tapered fingers. We identified a de novo GNB2 variant c.229G>A, p.(Gly77Arg). Notably, pathogenic substitutions of the homologous Gly77 residue including an identical variant (p.Gly77Arg, p.Gly77Val, p.Gly77Ser, p.Gly77Ala) of GNB1, a paralog of GNB2, was reported in individuals with global developmental delay and hypotonia. Clinical features of our case overlap with those of GNB1 variants. Our study suggests that a GNB2 variant may be associated with syndromic global developmental delay.

Spectrum of Joint Deformities in Children with Juvenile Idiopathic Arthritis

OBJECTIVE

To determine the frequency and types of joint deformities in children with juvenile idiopathic arthritis and their association with clinical parameters and rheumatoid factor.

STUDY DESIGN

Cross-sectional study.

PLACE AND DURATION OF STUDY

Rheumatology Outpatient Clinic, the Children's Hospital and the Institute of Child Health, Lahore, from September 2014 to February 2015.

METHODOLOGY

All patients of both genders of less than 16 years of age, who fulfilled the International League of Association for Rheumatology (ILAR) criteria for Juvenile Idiopathic Arthritis (JIA), were enrolled in this study. Their demographic data, duration of disease at the time of presentation, types of JIA, various joint deformities and rheumatoid factor (RF) were documented. Statistical analysis of data was done on SPSS version 16. Chi-square test was applied to determine the association of clinical deformity with age of patients, disease duration at presentation, types of JIA and RF.

RESULTS

Out of 70 patients enrolled during the study period, 51.4% were boys with mean age at presentation being 9.44 ±3.89 years (2-7 years) and median duration of disease being 24 months (interquartile range 42 months). Forty patients (57.1%) had joint deformities. Most common joints involved were hand (50%), wrist (50%), and knee (35.7%). The common types of joint deformities were boutonniere deformity (28.6%), ulnar deviation of wrist (28.6%), fixed flexion deformity of wrist (22.9%), and knee (31.4%). The most common type of JIA was polyarthritis RF negative with or without deformity. There was a strong association of deformities with older age of patients at presentation (p=0.036), longer duration of disease at presentation (p=0.028), polyarthritis (RF seronegative / seropositive) (p=0.013), and seropositivity (p=0.04).

CONCLUSION

More than 50% patients with JIA have joint deformities. Joint deformities are more likely to be seen in children with long-standing disease, those with polyarthritis JIA and seropositive patients.

Congenital Zika syndrome with arthrogryposis: retrospective case series study

OBJECTIVE

To describe the clinical, radiological, and electromyographic features in a series of children with joint contractures (arthrogryposis) associated with congenital infection presumably caused by Zika virus.

DESIGN

Retrospective case series study.

SETTING

Association for Assistance of Disabled Children, Pernambuco state, Brazil.

PARTICIPANTS

Seven children with arthrogryposis and a diagnosis of congenital infection presumably caused by Zika virus during the Brazilian microcephaly epidemic.

MAIN OUTCOME MEASURES

Main clinical, radiological, and electromyographic findings, and likely correlation between clinical and primary neurological abnormalities.

RESULTS

The brain images of all seven children were characteristic of congenital infection and arthrogryposis. Two children tested positive for IgM to Zika virus in the cerebrospinal fluid. Arthrogryposis was present in the arms and legs of six children (86%) and the legs of one child (14%). Hip radiographs showed bilateral dislocation in seven children, subluxation of the knee associated with genu valgus in three children (43%), which was bilateral in two (29%). All the children underwent high definition ultrasonography of the joints, and there was no evidence of abnormalities. Moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography (monopolar). Five of the children underwent brain computed tomography (CT) and magnetic resonance imaging (MRI) and the remaining two CT only. All presented malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. MRI of the spine in four children showed apparent thinning of the cord and reduced ventral roots.

CONCLUSIONS

Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis. The arthrogryposis was unrelated to the abnormalities of the joints themselves, but was possibly of neurogenic origin, with chronic involvement of central and peripheral motor neurones leading to deformities as a result of fixed postures in utero. Based on the neurophysiological observations, we suggest two possible mechanisms: tropism of neurones, with involvement of peripheral and central motor neurones, or a relation with vascular disorders.

[ASBMR 2013 REPORT. Meeting Report on the ASBMR. Topics for basic research at ASBMR 2013]

This is the brief report on basic research at ASBMR 2013 held in Baltimore, MD, USA. I focused on the research about osteoarthritis and skeletal development and introduce a part of current topics referring to past reports.

[Clinical predictors for the phenotypic heterogeneity of severe hemophilia A in China]

OBJECTIVE

To observe the phenotypic heterogeneity of severe hemophilia A in China and investigate the clinical factors for defining the severity of the clinical presentations.

METHODS

The data including the age of first bleeding and first joint bleeding, bleeding frequency, the number of joint deformities and body mass index (BMI) were collected from 223 patients with severe hemophilia A (FVIII:C≤2%).

RESULTS

The median age at first bleeding was 1 year (range: 0-35 years). The percentages of patients with first bleeding age<1 year, ≥2 years and ≥6 years were 44.3% (94/212), 34.4% (73/212), and 10.8% (23/212), respectively. The median age at first joint bleeding was 2.25 years. The percentages of patients with first joint bleeding age ≤1 year, ≥2 years and ≥6 years were 25.5% (24/94), 57.4% (54/94), and 18.1% (17/94), respectively. The percentage of patients who did not have joint bleeding was 7.4% (7/94). The median annual bleeding frequency was 24 per year (range: 1-120), and the proportion of patients with annual bleeding episodes of less than 6 times was 12.9%. Only 24.7% of the patients were free of any joint deformities. Analysis showed that milder cases had older ages of first bleeding and first joint bleeding than the severe cases, and the milder cases had also significantly lower BMI.

CONCLUSION

The age of first bleeding and first joint bleeding and BMI may predict the clinical severity of hemophilia A in China in the early stage.

Prolyl 3-hydroxylase-1 null mice exhibit hearing impairment and abnormal morphology of the middle ear bone joints

Prolyl 3-hydroxylase1 (P3H1) is a collagen modifying enzyme which hydroxylates certain prolines in the Xaa position of conventional GlyXaaYaa triple helical sequence. Recent investigations have revealed that mutations in the LEPRE1 (gene encoding for P3H1) cause severe osteogenesis imperfecta (OI) in humans. Similarly LEPRE1 knockout mice display an OI-like phenotype. Significant hearing loss is a common problem for people with osteogenesis imperfecta. Here we report that hearing of the P3H1 null mice is substantially affected. Auditory brainstem responses (ABRs) of the P3H1 null mice show an average increase of 20-30 dB in auditory thresholds. Three dimensional reconstructions of the mutant middle ear bones by Micro-scale X-ray computed tomography (Micro-CT) demonstrate abnormal morphology of the incudostapedial and incudomalleal joints. We establish the LEPRE1 knockout mouse as a valuable model system to investigate the mechanism of hearing loss in recessive OI.

An autosomal recessive syndrome of joint contractures, muscular atrophy, microcytic anemia, and panniculitis-associated lipodystrophy

CONTEXT

Genetic lipodystrophies are rare disorders characterized by partial or complete loss of adipose tissue and predisposition to insulin resistance and its complications such as diabetes mellitus, hypertriglyceridemia, hepatic steatosis, acanthosis nigricans, and polycystic ovarian syndrome.

OBJECTIVE

The objective of the study was to report a novel autosomal recessive lipodystrophy syndrome.

RESULTS

We report the detailed phenotype of two males and one female patient, 26-34 yr old, belonging to two pedigrees with an autosomal recessive syndrome presenting with childhood-onset lipodystrophy, muscle atrophy, severe joint contractures, erythematous skin lesions, and microcytic anemia. Other variable clinical features include hypergammaglobulinemia, hepatosplenomegaly, generalized seizures, and basal ganglia calcification. None of the patients had diabetes mellitus or acanthosis nigricans. Two had mild hypertriglyceridemia and all had low levels of high-density lipoprotein cholesterol. Skin biopsy of an erythematous nodular skin lesion from one of the patients revealed evidence of panniculitis. The lipodystrophy initially affected the upper body but later became generalized involving abdomen and lower extremities as well.

CONCLUSIONS

We conclude that these patients represent a novel autoinflammatory syndrome resulting in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy. The molecular genetic basis of this disorder remains to be elucidated.

Abnormal radiographic findings in 865 French Standardbred trotters and their relationship to racing performance

REASON FOR PERFORMING STUDY

Developmental orthopaedic lesions are commonly found in French Standardbred horses. One of the main questions asked by trainers, owners and veterinarians is what impact these lesions have on the racing career and racing performances of horses.

OBJECTIVES

To study the prevalence and distribution of developmental orthopaedic lesions in young French Standardbred trotters and to relate them to racing performance.

METHODS

Feet, fetlock, tarsus and stifle regions were radiographed in 865 two-year-old French Standardbred trotters. Abnormal radiographic findings (ARF) were evaluated for 12 anatomical sites identified in these areas, and a severity index given. Performance criteria were: success in qualification for racing, maximal and mean index of trot (ITR), an annual index calculated on the basis of the logarithm of earnings per starts, total earnings at 5 years, placed races compared to starts and longevity of the racing career. Analysis of variance were calculated to study the relationships between racing performance and the number of ARF or the severity index.

RESULTS

A total of 363 horses (42.0%) showed ARF. Prevalence of ARF was 18.3% in the plantar aspect of the hind fetlock and 10.6% in the proximal tarsus. Among the total population, 833 horses were considered for performance evaluation, 478 of them were qualified for racing. The number of ARF significantly affected racing longevity. However, the number of ARF did not affect performance categories according to maximal ITR. Concerning distribution of ARF, the number of plantar lesions in the fetlock significantly affected mean ITR. The index of severity did not provide more information for prognosis than the number of ARF.

CONCLUSION

Longevity is the only criteria affected by ARF. When evaluating different sites, only the plantar fetlock region showed a significant relationship with mean ITR.

POTENTIAL RELEVANCE

Number of ARF and radiographic score (RS) affect mean ITR and longevity but do not affect maximal ITR. A horse with a good racing ability will be a good performer but might have a racing career shortened because of orthopaedic problems in relation to developmental orthopaedic lesions.

Bartsocas-Papas syndrome

We report three sibs born to a third degree consanguineous Indian family affected with Bartsocas Papas Syndrome. All the three pregnancies were complicated by severe oligohydramnios, which is not commonly seen with Bartsocas-Papas syndrome.

Shox2-deficiency leads to dysplasia and ankylosis of the temporomandibular joint in mice

The temporomandibular joint (TMJ) is a unique synovial joint whose development differs from the formation of other synovial joints. Mutations have been associated with the developmental defects of the TMJ only in a few genes. In this study, we report the expression of the homeobox gene Shox2 in the cranial neural crest derived mesenchymal cells of the maxilla-mandibular junction and later in the progenitor cells and undifferentiated chondrocytes of the condyle as well as the glenoid fossa of the developing TMJ. A conditional inactivation of Shox2 in the cranial neural crest-derived cells causes developmental abnormalities in the TMJ, including dysplasia of the condyle and glenoid fossa. The articulating disc forms but fuses with the fibrous layers of the condyle and glenoid fossa, clinically known as TMJ ankylosis. Histological examination indicates a delay in development in the mutant TMJ, accompanied by a significantly reduced rate of cell proliferation. In situ hybridization further demonstrates an altered expression of several key osteogenic genes and a delayed expression of the osteogenic differentiation markers. Shox2 appears to regulate the expression of osteogenic genes and is essential for the development and function of the TMJ. The Shox2 conditional mutant thus provides a unique animal model of TMJ ankylosis.

A 15Mb duplication of 6q24.1-q25.3 associated with typical but milder features of the duplication 6q syndrome

We report on a female patient carrying a de novo 15Mb duplication of 6q24.1-q25.3 detected by conventional karyotyping and fine-mapped by molecular karyotyping with a 250K SNP array. Pure interstitial duplications of 6q are rarely reported in the literature and none of them exactly mapped by array technique so far. Our patient shows typical aspects of the "duplication 6q" syndrome such as hypertelorism, downslanting palpebral fissures, carp shaped mouth and joint contractures, but milder mental retardation and no growth retardation.

[Axes of the legs in childhood. What is pathologic?]

At birth the lower extremity is characterized by a varus axis in the lower leg and the knee joint in the frontal plane (bowleg) and an increased femoral antetorsion and a neutral or increased medial torsion of the lower leg in the transverse plane. By the time growth is complete a normal valgus axis of 5-9 degrees has developed in the lower limb and the femoral antetorsion has decreased to about 15 degrees. The lower leg will show a normal external rotation of 15 degrees on average. The evolution of the axis values in the lower extremity is influenced by changing compressive and propelling forces acting on the growth plates as the child adopts an upright posture. There is a wide range of normal values, but pathologic development of the leg axes is rare and mostly idiopathic. Secondary deviations of the axis from normal can occur. Careful clinical examinations are necessary to differentiate between pathologic and physiological variations. Further apparative diagnostic procedures help to elucidate the etiology and are essential for surgical planning. Nonoperative treatment alone is rarely sufficient to influence the deformity.

Deletion of Tgfbr2 in Prx1-cre expressing mesenchyme results in defects in development of the long bones and joints

In this study, we address the function of Transforming Growth Factor beta (TGF-beta) and its type II receptor (Tgfbr2) in limb development in vivo. Mouse embryos were generated in which the Tgfbr2 gene was deleted in early limb mesenchyme using Prx1Cre-mediated LoxP recombination. A high level of Tgfbr2 gene deletion was verified in limb mesenchyme by PCR between E9.5 and E10.5 days in Cre expressing mice. RT-PCR assays indicated a significant depletion of Tgfbr2 mRNA by E10.5 days as a result of Cre mediated gene deletion. Furthermore, limb mesenchyme from Cre(+);Tgfbr2(f/f) mice placed in micromass culture did not respond to exogenously added TGF-beta1 confirming the functional deletion of the receptor. However, there was an unexpected increase in the number and intensity of Alcian blue stained chondrogenic nodules in micromass cultures derived from Tgfbr2-deleted limbs relative to cultures from control limbs suggesting that Tgfbr2 normally limits chondrogenesis in vitro. In vivo, early limb development and chondrocyte differentiation occurred normally in Tgfbr2-depleted mice. Later in development, depletion of Tgfbr2 in limb mesenchyme resulted in short limbs and fusion of the joints in the phalanges. Alteration in the length of the long bones was primarily due to a decrease in chondrocyte proliferation after E13.5 days. In addition, the transition from prehypertrophic to hypertrophic cells was accelerated while there was a delay in late hypertrophic differentiation leading to a reduction in the length of the marrow cavity. In the joint, cartilage cells replaced interzone cells during development. Analysis of markers for joint development indicated that the joint was specified properly and that the interzone cells were initially formed but not maintained. The results suggest that Tgfbr2 is required for normal development of the skeleton and that Tgfbr2 can act to limit chondrogenesis in mesenchymal cells like the interzone.

A new lethal case of joint contractures, facial abnormalities, pachygyria plus early-onset encephalopathy with a suppression-burst EEG pattern

Pachygyria, joint contractures and facial abnormalities have been reported in the literature very rarely. These features constitute a new lethal syndrome. We describe a male infant who represents an additional case of the same lethal syndrome first described in 1989. The patient also presented an early-onset epileptic encephalopathy with a suppression-burst EEG pattern.

Type I collagen is a genetic modifier of matrix metalloproteinase 2 in murine skeletal development

Recessive inactivating mutations in human matrix metalloproteinase 2 (MMP2, gelatinase A) are associated with syndromes that include abnormal facial appearance, short stature, and severe bone loss. Mmp2(-/-) mice have only mild aspects of these abnormalities, suggesting that MMP2 function is redundant during skeletal development in the mouse. Here, we report that Mmp2(-/-) mice with additional mutations that render type I collagen resistant to collagenase-mediated cleavage to TC(A) and TC(B) fragments (Col1a1(r/r) mice) have severe developmental defects resembling those observed in MMP2-null humans. Composite Mmp2(-/-);Col1a1(r/r) mice were born in expected Mendelian ratios but were half the size of wild-type, Mmp2(-/-), and Col1a1(r/r) mice and failed to thrive. Furthermore, composite Mmp2(-/-);Col1a1(r/r) animals had very abnormal craniofacial features with shorter snouts, bulging skulls, incompletely developed calvarial bones and unclosed cranial sutures. In addition, trabecular bone mass was reduced concomitant with increased numbers of bone-resorbing osteoclasts and osteopenia. In vitro, MMP2 had a unique ability among the collagenolytic MMPs to degrade mutant collagen, offering a possible explanation for the genetic interaction between Mmp2 and Col1a1(r). Thus, because mutations in the type I collagen gene alter the phenotype of mice with null mutations in Mmp2, we conclude that type I collagen is an important modifier gene for Mmp2. Developmental Dynamics 236:1683-1693, 2007. (c) 2007 Wiley-Liss, Inc.

Arthropathy of neonatal onset multisystem inflammatory disease (NOMID/CINCA)

BACKGROUND

Neonatal onset multisystem inflammatory disease (NOMID), an autoinflammatory disease, is characterized by fever, chronic urticarial rash, CNS manifestations, and arthropathy. Approximately 50% of patients with NOMID have de novo missense mutations in CIAS1, which is associated with modulation of the IL-1b and apoptotic pathways. Approximately 60% of NOMID patients have prominent arthropathy, most commonly involving the knees, the cause of which remains poorly understood.

OBJECTIVE

To more fully describe the findings of NOMID arthropathy on MRI and radiography and to provide a better understanding of the origin of the bony lesions.

MATERIALS AND METHODS

We imaged 20 patients with NOMID to further investigate NOMID-associated bony lesions.

RESULTS

Bony abnormalities were seen in the knees of 11/20 patients. The knee findings included enlarged, deformed femora and patellae in all and tibiae in the majority, without evidence of synovitis. Some patients had other joint involvement. Most had short stature and valgus or varus knee deformities. No association was noted between bony abnormalities and CIAS1 mutations. The abnormalities appeared to be the result of a mass-producing process. The resulting heterogeneously calcified masses appeared to originate in the physis and deformed the adjacent metaphysis and epiphysis.

CONCLUSION

These findings suggest that the arthropathy of NOMID is the result of abnormal endochondral bone growth. Further investigation is needed to determine whether this deformity is triggered by inflammation early in development or by CIAS1 mutations causing abnormal chondrocyte apoptosis.

Role of canonical Wnt-signalling in joint formation

The individual elements of the vertebrate skeleton are separated by three different types of joints, fibrous, cartilaginous and synovial joints. Synovial joint formation in the limbs is coupled to the formation of the prechondrogenic condensations, which precede the formation of the joint interzone. We are beginning to understand the signals involved in the formation of prechondrogenic condensations and the subsequent differentiation of cells within the condensations into chondrocytes. However, relatively little is known about the molecules and molecular pathways involved in induction of the early joint interzone and the subsequent formation of the synovial joints. Based on gain-of function studies Wnt-signalling, in particular the canonical pathway, has been implicated in the joint induction process. Here we provide genetic evidence from loss-of function analysis of embryos lacking either the central player of the canonical Wnt-pathway, beta-catenin, in the limb mesenchyme or the two ligands, Wnt9a and Wnt4, demonstrating that canonical Wnt-signalling plays an important role in suppressing the chondrogenic potential of cells in the joint thereby actively allowing joint formation. Furthermore our data show that the beta-catenin activity is not essential for the induction of molecular markers expressed in the joint interzone. Thus, suggesting that canonical Wnt-signalling is not required for the induction, but for the subsequent maintenance of the fate of the joint interzone cells.

Aberrant MHC class II expression in mouse joints leads to arthritis with extraarticular manifestations similar to rheumatoid arthritis

Genetic susceptibility to rheumatoid arthritis (RA) is associated with certain MHC class II molecules. To clarify the role of these determinants in RA, we generated the D1CC transgenic mouse that expressed genes involved in antigen processing and presentation by the MHC class II pathway in joints. The class II transactivator, which was transcribed from the rat collagen type II promoter and enhancer, directed the expression of these genes. In D1CC mice congenic for the H-2(q) (DBA/1) background, small amounts of bovine collagen type II in adjuvant induced reproducibly an inflammatory arthritis resembling RA. Importantly, these stimuli had no effect in DBA/1 mice. Eighty-nine percent of D1CC mice developed chronic disease with joint swelling, redness, and heat in association with synovial proliferation as well as pannus formation and mononuclear infiltration of synovial membranes. Granulomatous lesions resembling rheumatoid nodules and interstitial pneumonitis also were observed. As in patients with RA, anticyclic citrullinated peptide antibodies were detected during the inflammatory stage. Finally, joints in D1CC mice displayed juxtaarticular demineralization, severe joint space narrowing, and erosions, which led to ankylosis, but without the appearance of osteophytes. Thus, aberrant expression of MHC class II in joints facilitates the development of severe erosive inflammatory polyarthritis, which is very similar to RA.

Unilateral congenital elbow luxation in a dachshund

Congenital elbow luxation was diagnosed in a 12-week-old, intact male, dachshund with a lateral elbow prominence and mild lameness of the right forelimb. Closed reduction of the radial head, ulnar ostectomy, and external stabilization of the joint were performed. Function was returned to the limb, but radial head and ulnar subluxation persisted.

First Trimester Ultrasound Diagnosis of Lethal Multiple Pterygium Syndrome

OBJECTIVE

Diagnosis of lethal multiple pterygium syndrome in the first trimester of pregnancy.

METHODS

A 38-year-old woman attended our ultrasound (US) clinic at 11.2 weeks gestation. She has had two previous stillbirths affected by lethal multiple pterygium syndrome. Transabdominal and transvaginal US were performed and identified a recurrence. Autopsy findings are compared to the fetal US findings.

RESULTS

Fetal US showed a markedly increased nuchal translucency, fixed flexion deformities of the elbows and knees bilaterally, cutaneous webs across both elbow joints and absent fetal movements. The patient decided to terminate the pregnancy and a D&C was performed. Pathology of intact fetal parts showed flexion deformity of the right elbow with a cutaneous web, and ulnar deviation of the right wrist.

CONCLUSION

Increased nuchal translucency, absent limb movements, multiple joint contractures and cutaneous webs on US allowed the diagnosis of lethal multiple pterygium syndromes in the first trimester of pregnancy.

Forced chondrocyte expression of sonic hedgehog impairs joint formation affecting proliferation and apoptosis

Proliferation and apoptosis are two fundamental processes that occur during limb development, and in particular in joint formation. To study the role of hedgehog proteins in limbs, we have misexpressed Sonic Hedgehog specifically in chondrocytes. We found that the appendicular skeleton was severely misshapen while pelvic and shoulder girdles developed normally. In particular, we detected fusion of the elbow/knee joint, no definite carpal/tarsal, metacarpal/metatarsal bones and absence of distinct phalanges, fused in a continuous cartilaginous rod. Molecular markers of joints, such as Gdf5 and sFrp2 were absent at presumptive joint sites and Tenascin C, a molecule associated with joint formation and expressed in permanent cartilage, was expressed in a wider region in transgenic animals as compared to the wild type. The ratio of proliferating to non-proliferating chondrocytes was about two times higher in transgenic developing cartilage as compared to the wild type. Accordingly, the proapoptotic gene Bax was barely detectable in the growth plate of transgenic mice and Tunel assay showed the absence of apoptosis in presumptive joints at E15.5. Taken together, these results suggest that misexpression of Sonic Hedgehog causes apoptosis and proliferation defects leading to the lack of joint cavity and fusion of selected limb skeletal elements.

Clinical study of hereditary disorders of connective tissues in a Chilean population: joint hypermobility syndrome and vascular Ehlers-Danlos syndrome

OBJECTIVE

To demonstrate the high frequency and lack of diagnosis of joint hypermobility syndrome (JHS) and the seriousness of vascular Ehlers-Danlos syndrome (VEDS).

METHODS

Two hundred forty-nine Chilean patients with hereditary disorders of the connective tissues (CTDs) and 64 control subjects were evaluated for the diagnoses of JHS and VEDS using the validated Brighton criteria, as compared with the traditional Beighton score. In addition, the presence of blue sclera was determined, with the degree of intensity graded as mild, moderate, or marked.

RESULTS

The frequency of hereditary CTDs was 35%, with diagnoses of JHS in 92.4% of subjects, VEDS in 7.2%, and osteogenesis imperfecta in 0.4%. The Beighton score proved to be insufficient for the diagnosis of JHS (35% of subjects had a negative score), whereas the Brighton criteria yielded positive findings (a diagnosis of JHS) in 39% of control subjects. Blue sclera was frequent, being identified in 97% of JHS patients and 94% of VEDS patients. Moderate osteopenia/osteoporosis was observed in 50% of patients with VEDS and 26% of those with JHS. Dysautonomia, dyslipidemia, and scoliosis were more frequent in VEDS patients than in JHS patients. The typical JHS facial appearance and the "hand holding the head sign" were identified. Raynaud's phenomenon was extremely rare in JHS patients (2%). Ruptured uterus and cerebral aneurysm occurred in 12% and 6% of VEDS patients, respectively. Spontaneous pneumothorax was more frequent in VEDS patients (11%) than in JHS patients (0.9%).

CONCLUSION

JHS is very frequent but usually undiagnosed. The Beighton score is an insufficient method for JHS diagnosis. We recommend that physicians learn to recognize the typical facial features of JHS and be able to identify blue sclera. We also propose that validated hypermobility criteria be routinely used. Further research is needed to determine why the prevalence of JHS is so high in Chile.

Testicular cancer in a patient with Primrose syndrome

A mentally retarded, adult man was found to have joint contractures, sparse body hair, hearing loss, dysmorphic facial features, large calcified pinnae and a huge torus palatinus. All features are similar to those earlier described in patients with Primrose syndrome. In addition he developed a germ cell tumour of his right testicle at age 27 years. A comparison is provided between the main findings in the four previously reported cases with Primrose syndrome and the current patient. Calcification of the pinnae is an infrequent symptom in the general population, and a torus palatinus of limited size is commonly found but a torus of the size reported here is extremely unusual. Both symptoms are excellent handles for diagnosing this entity. It remains as yet uncertain whether an increased risk to malignancies forms part of this syndrome or is only a consequence of cryptorchidism in this patient.

Review of the literature: elbow incongruity in the dog

Elbow incongruity is the term to describe bad alignment of the joint surfaces of the elbow. Two features illustrate incongruity of the elbow: an abnormal shape of the ulnar trochlear notch and a step between the radius and ulna, caused by either a short radius or a short ulna. It has been suggested that both an elliptical notch, and a step, can cause increased local pressure within the joint, resulting in loose fragments at different locations: ununited anconeal process (UAP), fragmented coronoid process (FCP), osteochondritis dissecans of the humeral condyle (OCD). These lesions are grouped under the term 'elbow dysplasia' and are the most frequent causes of front leg lameness in the dog. Although several radiographic features to diagnose incongruity have been described, the 'scoring' of incongruity is subjective because there is currently no objective method to measure the degree of incongruity. Because superimposition is avoided, CT is suggested as a standard technique to measure incongruity. Arthroscopy on the other hand, allows the direct visualisation of the intra-articular structures and their abnormalities. Information on both techniques are still relatively new. Several surgical techniques have been proposed to restore joint congruity; the one most frequently used is an ulnar osteotomy. But because of possible complications, other techniques are being developed. Reports evaluating the results of the different techniques are not yet available.

Targeted disruption of Mig-6 in the mouse genome leads to early onset degenerative joint disease

Degenerative joint disease, also known as osteoarthritis, is the most common joint disorder in human beings. The molecular mechanism underlying this disease is not fully understood. Here, we report that disruption of mitogen-inducible gene 6 (Mig-6) in mice by homologous recombination leads to early onset degenerative joint disease, which is revealed by simultaneous enlargement and deformity of multiple joints, degradation of articular cartilage, and the development of bony outgrowths or osteophyte formation within joint space. The osteophyte formation appears to be derived from proliferation of mesenchymal progenitor cells followed by differentiation into chondrocytes. Absence of the Rag2 gene does not rescue the joint phenotype, excluding a role for the acquired immune system in the development of this disease. Our results provide insight into the mechanism of osteoarthritis by showing that loss of Mig-6 leads to early onset of this disease, implying that this gene or its pathway is important in normal joint maintenance. Because of the striking similarity of osteoarthritis in humans and mice, the Mig-6 mutant mouse should provide a useful animal model for studying the mechanism of this disease and for testing drugs or therapies for treating osteoarthritis.

Spastic paraplegia, optic atrophy, and neuropathy is linked to chromosome 11q13

We report an autosomal recessive neurodegenerative disorder in 25 white members from a large inbred Brazilian family, 22 of whom were evaluated clinically. This condition is characterized by (1) subnormal vision secondary to apparently nonprogressive congenital optic atrophy; (2) onset of progressive spastic paraplegia in infancy; (3) onset of progressive motor and sensory axonal neuropathy in late childhood/early adolescence; (4) dysarthria starting in the third decade of life; (5) exacerbated acoustic startle response; and (6) progressive joint contractures and spine deformities. Motor handicap was severe, and all patients were wheelchair bound after 15 years old. We performed a genome-wide screen including 25 affected individuals and 49 of their unaffected relatives. Linkage was detected at 11q13 region with a maximum logarithm of odds score of +14.43, obtained with marker D11S1883. The candidate region, which lies between D11S1908 and D11S1889, encompasses approximately 4.8Mb and has more than 100 genes and expressed sequences. We propose the acronym SPOAN (spastic paraplegia, optic atrophy, and neuropathy) for this complex syndrome.

Joint hypermobility syndrome in childhood. A not so benign multisystem disorder?

OBJECTIVES

Joint hypermobility (JH) or "ligamentous laxity" is felt to be an underlying risk factor for many types of musculoskeletal presentation in paediatrics, and joint hypermobility syndrome (JHS) describes such disorders where symptoms become chronic, often more generalized and associated with functional impairment. Clinical features are felt to have much in common with more severe disorders, including Ehlers-Danlos syndrome (EDS), osteogenesis imperfecta and Marfan syndrome, although this has not been formally studied in children. We defined the clinical characteristics of all patients with joint hypermobility-related presentations seen from 1999 to 2002 in a tertiary referral paediatric rheumatology unit.

METHODS

Patients were identified and recruited from paediatric rheumatology clinic and ward, and a dedicated paediatric rheumatology hypermobility clinic at Great Ormond Street Hospital. Data were collected retrospectively on the patients from the paediatric rheumatology clinics (1999-2002) and prospectively on patients seen in the hypermobility clinic (2000-2002). Specifically, historical details of developmental milestones, musculoskeletal or soft tissue diagnoses and symptoms, and significant past medical history were recorded. Examination features sought included measurements of joint and soft tissue laxity, and associated conditions such as scoliosis, dysmorphic features, cardiac murmurs and eye problems.

RESULTS

One hundred and twenty-five children (64 females) were included on whom sufficient clinical data could be identified and who had clinical problems ascribed to JH present for longer than 3 months. Sixty-four were from the paediatric rheumatology clinic and 61 from the hypermobility clinic. No differences were found in any of the measures between the two populations and results are presented in a combined fashion. Three-quarters of referrals came from paediatricians and general practitioners but in only 10% was hypermobility recognized as a possible cause of joint complaint. The average age at onset of symptoms was 6.2 yr and age at diagnosis 9.0 yr, indicating a 2- to 3-yr delay in diagnosis. The major presenting complaint was arthralgia in 74%, abnormal gait in 10%, apparent joint deformity in 10% and back pain in 6%. Mean age at first walking was 15.0 months; 48% were considered "clumsy" and 36% as having poor coordination in early childhood. Twelve per cent had "clicky" hips at birth and 4% actual congenital dislocatable hip. Urinary tract infections were present in 13 and 6% of the female and male cases, respectively. Thirteen and 14%, respectively, had speech and learning difficulties diagnosed. A history of recurrent joint sprains was seen in 20% and actual subluxation/dislocation of joints in 10%. Forty per cent had experienced problems with handwriting tasks, 48% had major limitations of school-based physical education activities, 67% other physical activities and 41% had missed significant periods of schooling because of symptoms. Forty-three per cent described a history of easy bruising. Examination revealed that 94% scored > or =4/9 on the Beighton scale for generalized hypermobility, with knees (92%), elbows (87%), wrists (82%), hand metacarpophalangeal joints (79%), and ankles (75%) being most frequently involved.

CONCLUSIONS

JHS is poorly recognized in children with a long delay in the time to diagnosis. Although there is a referral bias towards joint symptoms, a surprisingly large proportion is associated with significant neuromuscular and motor development problems. Our patients with JHS also show many overlap features with genetic disorders such as EDS and Marfan syndrome. The delay in diagnosis results in poor control of pain and disruption of normal home life, schooling and physical activities. Knowledge of the diagnosis and simple interventions are likely to be highly effective in reducing the morbidity and cost to the health and social services.

Joint hypermobility syndrome in childhood. A not so benign multisystem disorder?

OBJECTIVES

Joint hypermobility (JH) or "ligamentous laxity" is felt to be an underlying risk factor for many types of musculoskeletal presentation in paediatrics, and joint hypermobility syndrome (JHS) describes such disorders where symptoms become chronic, often more generalized and associated with functional impairment. Clinical features are felt to have much in common with more severe disorders, including Ehlers-Danlos syndrome (EDS), osteogenesis imperfecta and Marfan syndrome, although this has not been formally studied in children. We defined the clinical characteristics of all patients with joint hypermobility-related presentations seen from 1999 to 2002 in a tertiary referral paediatric rheumatology unit.

METHODS

Patients were identified and recruited from paediatric rheumatology clinic and ward, and a dedicated paediatric rheumatology hypermobility clinic at Great Ormond Street Hospital. Data were collected retrospectively on the patients from the paediatric rheumatology clinics (1999-2002) and prospectively on patients seen in the hypermobility clinic (2000-2002). Specifically, historical details of developmental milestones, musculoskeletal or soft tissue diagnoses and symptoms, and significant past medical history were recorded. Examination features sought included measurements of joint and soft tissue laxity, and associated conditions such as scoliosis, dysmorphic features, cardiac murmurs and eye problems.

RESULTS

One hundred and twenty-five children (64 females) were included on whom sufficient clinical data could be identified and who had clinical problems ascribed to JH present for longer than 3 months. Sixty-four were from the paediatric rheumatology clinic and 61 from the hypermobility clinic. No differences were found in any of the measures between the two populations and results are presented in a combined fashion. Three-quarters of referrals came from paediatricians and general practitioners but in only 10% was hypermobility recognized as a possible cause of joint complaint. The average age at onset of symptoms was 6.2 yr and age at diagnosis 9.0 yr, indicating a 2- to 3-yr delay in diagnosis. The major presenting complaint was arthralgia in 74%, abnormal gait in 10%, apparent joint deformity in 10% and back pain in 6%. Mean age at first walking was 15.0 months; 48% were considered "clumsy" and 36% as having poor coordination in early childhood. Twelve per cent had "clicky" hips at birth and 4% actual congenital dislocatable hip. Urinary tract infections were present in 13 and 6% of the female and male cases, respectively. Thirteen and 14%, respectively, had speech and learning difficulties diagnosed. A history of recurrent joint sprains was seen in 20% and actual subluxation/dislocation of joints in 10%. Forty per cent had experienced problems with handwriting tasks, 48% had major limitations of school-based physical education activities, 67% other physical activities and 41% had missed significant periods of schooling because of symptoms. Forty-three per cent described a history of easy bruising. Examination revealed that 94% scored > or =4/9 on the Beighton scale for generalized hypermobility, with knees (92%), elbows (87%), wrists (82%), hand metacarpophalangeal joints (79%), and ankles (75%) being most frequently involved.

CONCLUSIONS

JHS is poorly recognized in children with a long delay in the time to diagnosis. Although there is a referral bias towards joint symptoms, a surprisingly large proportion is associated with significant neuromuscular and motor development problems. Our patients with JHS also show many overlap features with genetic disorders such as EDS and Marfan syndrome. The delay in diagnosis results in poor control of pain and disruption of normal home life, schooling and physical activities. Knowledge of the diagnosis and simple interventions are likely to be highly effective in reducing the morbidity and cost to the health and social services.

Unilateral congenital elbow luxation in a Cavalier King Charles Spaniel

A 7-week-old, intact female, Cavalier King Charles Spaniel was evaluated for nonweight bearing lameness of the right forelimb. Type III unilateral congenital elbow luxation was diagnosed radiographically. After surgical reduction, temporary placement of a transarticular pin, and external splinting of the joint, full weight bearing was achieved. Radial head subluxation persisted.

Diverse range of fixed positional deformities and bone growth restraint provoked by flaccid paralysis in embryonic chicks

Pancuronium bromide (PB) is used in neonates and pregnant women to induce limp, flaccid paralysis in order to allow mechanical ventilation during intensive care. Such non-depolarizing neuromuscular blocking drugs are administered to 0.1% of all human births in the UK. In this study, we examined PB effects on skeletal development in chick embryos. PB treatment produced skeletal deformities associated with significant reduction in longitudinal growth of all appendicular elements. This was associated with greater cartilage to bone ratios, indicating a preferential reduction in osteogenesis. PB also increased the incidence of knee joint flexion and tibiotarsal joint hyperextension. In addition to limb, spinal and craniofacial deformities, flaccid immobility appears to convert the normal geometric pattern of weight gain to a simple arithmetic accretion. This novel study highlights the potentially harmful effects of pharmacologically induced flaccid immobility on chick embryonic skeletal development. Whilst in ovo avian development clearly differs from human, our findings may have implications for the fetus, premature and term neonate receiving such non-depolarizing neuromuscular blocking drugs.

Mice with targeted disruption of the fatty acid transport protein 4 (Fatp 4, Slc27a4) gene show features of lethal restrictive dermopathy

The fatty acid transport protein family is a group of evolutionarily conserved proteins that are involved in the cellular uptake and metabolism of long and very long chain fatty acids. However, little is known about their respective physiological roles. To analyze the functional significance of fatty acid transport protein 4 (Fatp4, Slc27a4), we generated mice with a targeted disruption of the Fatp4 gene. Fatp4-null mice displayed features of a neonatally lethal restrictive dermopathy. Their skin was characterized by hyperproliferative hyperkeratosis with a disturbed epidermal barrier, a flat dermal-epidermal junction, a reduced number of pilo-sebaceous structures, and a compact dermis. The rigid skin consistency resulted in an altered body shape with facial dysmorphia, generalized joint flexion contractures, and impaired movement including suckling and breathing deficiencies. Lipid analysis demonstrated a disturbed fatty acid composition of epidermal ceramides, in particular a decrease in the C26:0 and C26:0-OH fatty acid substitutes. These findings reveal a previously unknown, essential function of Fatp4 in the formation of the epidermal barrier.

Findings from a multidisciplinary clinical case series of females with Rett syndrome

Systematic data from a multidisciplinary clinical assessment of a large series of females with Rett syndrome (RS; n=87) is presented. Participants' ages ranged from 2 years 1 month to 44 years 10 months. Areas assessed included oromotor skills, feeding problems, growth, breathing abnormalities, mobility, postural abnormalities and joint deformities, epilepsy, hand use and stereotypies, self-care, and cognitive and communication skills. Many previously reported trends in the presentation of RS over time were confirmed, notably the increasingly poor growth and near pervasiveness of fixed joint deformities and scoliosis in adulthood. In contrast, there was a slight trend towards improved autonomic function in adulthood, whereas feeding difficulties increased into middle childhood and then reached a plateau. Improvements in mobility into adolescence were followed by a decline in those skills in adulthood. Levels of dependency were high, confirming findings from previous studies. Despite the presence of repetitive hand movements, a range of hand-use skills was seen in individuals of all ages. Cognitive and communication skills were limited, but there was little evidence of deterioration of these abilities with age. These findings confirm that RS is not a degenerative condition and indicate that intervention and support to maintain and increase motor skills, daily living skills, and cognitive and communicative functioning are appropriate targets for individuals with RS.

Multiple joint and skeletal patterning defects caused by single and double mutations in the mouse Gdf6 and Gdf5 genes

Growth/differentiation factors 5, 6, and 7 (GDF5/6/7) represent a distinct subgroup within the bone morphogenetic protein (BMP) family of secreted signaling molecules. Previous studies have shown that the Gdf5 gene is expressed in transverse stripes across developing skeletal elements and is one of the earliest known markers of joint formation during embryonic development. Although null mutations in this gene disrupt formation of some bones and joints in the skeleton, many sites are unaffected. Here, we show that the closely related family members Gdf6 and Gdf7 are expressed in different subsets of developing joints. Inactivation of the Gdf6 gene causes defects in joint, ligament, and cartilage formation at sites distinct from those seen in Gdf5 mutants, including the wrist and ankle, the middle ear, and the coronal suture between bones in the skull. Mice lacking both Gdf5 and Gdf6 show additional defects, including severe reduction or loss of some skeletal elements in the limb, additional fusions between skeletal structures, scoliosis, and altered cartilage in the intervertebral joints of the spinal column. These results show that members of the GDF5/6/7 subgroup are required for normal formation of bones and joints in the limbs, skull, and axial skeleton. The diverse effects on joint development and the different types of joints affected in the mutants suggest that members of the GDF family play a key role in establishing boundaries between many different skeletal elements during normal development. Some of the skeletal defects seen in single or double mutant mice resemble defects seen in human skeletal diseases, which suggests that these genes may be candidates that underlie some forms of carpal/tarsal coalition, conductive deafness, scoliosis, and craniosynostosis.

Postnatal growth failure, microcephaly, mental retardation, cataracts, large joint contractures, osteoporosis, cortical dysplasia, and cerebellar atrophy

We describe two sibs with postnatal-onset growth deficiency, microcephaly, cataract, prominent supraorbital ridge, large joint contractures, severe osteoporosis, cortical dysplasia, cerebellar atrophy, and mental retardation. The combination appears to constitute a previously undescribed syndrome inherited in an autosomal recessive pattern.

Stüve-Wiedemann syndrome in children surviving infancy: clinical and radiological features

We report three children from two inbred Arab families with Stüve-Wiedemann syndrome who have survived the first year of life (ages are 6 years, 2.8 years and 2 years). All exhibited a characteristic phenotype resembling that described by Chen et al.[(2001). Am J Med Genet 101:240-245]. In all three children the skeletal abnormalities progressed to severe bowing of the long bones with prominent joints and severe spinal deformity. Neurological symptoms were present in all of them. These included temperature instability with excessive sweating, reduced pain sensation with repeated injury to the tongue and limbs, absent corneal reflexes and a smooth tongue. Mentality was normal in all of them. Radiological changes included under tubulation of the diaphyses, rarefaction and striation of metaphyses, destruction of the femoral heads and spinal deformity. We confirm that survival in this syndrome is possible and that the prognosis improves after the first year of life. This should be taken into consideration when counselling parents of affected children. This report further supports the existence of a characteristic phenotype in Stüve-Wiedemann syndrome survivors which include, in addition to the skeletal abnormalities and distinctive radiological features, neurological symptoms reminiscent of dysautonomia.

Cervical spine involvement in Larsen's syndrome: a case illustration

We present the progressive clinical course of a child with myelopathy attributable to cervical spine abnormalities associated with Larsen's syndrome. After anterior and posterior cervical fusion, his preoperative symptoms of weakness, gait dysfunction, and hyperreflexia have improved at 9-month follow-up. The progressive course and importance of early referral and intervention should be of interest to the general pediatric community.

Osteological and morphometric observations on intervertebral joints in the canine pre-diaphragmatic thoracic spine (Th1-Th9)

The incidence of facet aplasia was investigated in three groups of pure-bred dogs. We examined large breeds (Rough Collies, Doberman Pinschers, Rottweilers, Bernese Mountain Dogs, German Shepherd Dogs), chondrodystrophic breeds (Dachshunds, Pekinese dogs), and small breeds (Yorkshire Terriers, Maltese dogs). Uni- or bilateral aplasia of zygapophyseal (facet) joints was exclusively found in juvenile and adult small dogs, in which the incidence of aplasia ranged from between 26% (Th1) and 63% (Th8). There was no evidence that aplasia of zygapophyseal joints increases the risk of developing intervertebral disc disease or deformative spondylosis in small breeds. By applying the findings of previous empirical studies on intervertebral disc geometry and its biomechanical behaviour on the present morphometric results, there was an indication that the intervertebral disc may well compensate for the functional loss of aplastic zygapophyseal joints in small dogs. Biomechanical factors and their potential role as inducing agents of facet aplasia in the pre-diaphragmatic thoracic spine are also discussed.

[A case of Satoyoshi syndrome complicating marginal gingivitis of the mandible and dislocation of the temporomandibular joint]

Satoyoshi syndrome is a very rare disorder, characterized by progressive painful intermittent muscle spasms beginning in adolescence. Universal alopecia, diarrhea, amenorrhea and bony deformities are also cardinal features of this syndrome. Skeletal abnormalities, such as joint deformity, epiphysial destruction and retarded growth, are observed in approximately half of patients. However, no bony changes have previously been reported in the region of the head. We present here a male patient with Satoyoshi syndrome. Muscle cramps began in the lower extremities when he was 13 years old, and gradually spread. At the age of 17 years, masticatory muscle cramps made it difficult to eat and speak fluently, and were considered a cause of malacia in this patient. Finally, recurrent severe cramps in the masseter muscles caused marginal gingivitis of the mandible, necessitated extraction of the teeth and caused dislocation of the temporomandibular joint. After treatment with dantrolen sodium at doses up to 150 mg/day, painful spasm decreased significantly. Since masticatory muscles can cause significant stress to the teeth and the temporomandibular joint, sufficient attention should be paid to the oral region to avoid complications in patients with Satoyoshi syndrome.

Bilateral congenital diastasis of the inferior tibiofibular joint

Bilateral congenital inferior tibiofibular diastasis is an extremely rare anomaly of unknown etiology. A few cases have been reported previously. The author presents a case in which bilateral tibiofibulotalar arthrodesis was performed.

Early second trimester prenatal diagnosis of Neu-Laxova syndrome

Neu-Laxova is a rare, uniformly lethal, autosomal recessive condition with characteristic limb posturing, facial dysmorphic features, and central nervous system abnormalities. Forty-two cases of Neu-Laxova syndrome have been reported, with only four of these diagnosed prenatally. Three of the four cases were diagnosed at or after 32 weeks' gestation. The fourth case was diagnosed at 22 weeks' gestation in a patient who was followed with serial ultrasound studies due to having a prior affected child. At 19 weeks' gestation, we present the earliest reported prenatal diagnosis of Neu-Laxova syndrome in a primigravida with a non-informative family history.

Short stature, abnormal face, joint laxity, dislocation, hernias, delayed bone age, and severe psychomotor retardation in two brothers: previously undescribed MCA/MR syndrome

We describe two brothers with severe psychomotor retardation, short stature, microbrachycephaly, flat occiput, ptosis, low set and prominent ears, "beaked" nose, joint hyperlaxity and dislocation, hernias, delayed bone age, and abnormalities on skin biopsy. Their parents are first cousins. To the best of our knowledge, this syndrome has not been reported before.

Joint deformity patterns in severely physically disabled patients

Deformity patterns of the spine and upper and lower extremities were investigated in 64 patients with severe physical disability. Among the subjects, C-shaped and S-shaped scoliosis was found in 48 and nine, respectively. The hips were windblown in 20, adducted in 22, and abducted in seven. Knees were flexed in 39 and extended in four. Deformities of the ankle and upper extremities were variable. The most common combination, which was C-shaped scoliosis with convexity to the adducted side of hips, windblown hips, flexed knees, and dorsiflexed ankles, was noted among nine patients. Joint deformity patterns in the 43 patients with spastic tetraplegia were not significantly different from those in the 21 patients with dyskinesia.

Differential regulation of endochondral bone growth and joint development by FGFR1 and FGFR3 tyrosine kinase domains

Fibroblast growth factor receptors (FGFR) 1 and 3 have distinct mitogenic activities in vitro. In several cultured cell lines, FGFR1 transmits a potent mitogenic signal, whereas FGFR3 has little or no mitogenic activity. However, in other in vitro assays the FGFR3 intracellular domain is comparable with that of FGFR1. In vivo, FGFR3 negatively regulates chondrocyte proliferation and differentiation, and activating mutations are the molecular etiology of achondroplasia. By contrast, FGFR1 transmits a proliferative signal in various cell types in vivo. These observations suggest that inhibition of the proliferating chondrocyte could be a unique property of FGFR3 or, alternatively, a unique property of the proliferating chondrocyte. To test this hypothesis, FGFR1 signaling was activated in the growth plate in cells that normally express FGFR3. Comparison of transgenic mice with an activated FGFR1 signaling pathway with an achondroplasia-like mouse that expresses a similarly activated FGFR3 signaling pathway demonstrated that both transgenes result in a similar achondroplasia-like dwarfism. These data demonstrate that suppression of mitogenic activity by FGFR signaling is a property that is unique to growth plate chondrocytes. Surprisingly, we observed that in transgenic mice expressing an activated FGFR, some synovial joints failed to develop and were replaced by cartilage. The defects in the digit joints phenocopied the symphalangism that occurs in Apert syndrome and the number of affected joints was dependent on transgene dose. In contrast to the phenotype in the growth plate, the joint phenotype was more severe in transgenic mice with an activated FGFR1 signaling pathway. The failure of joint development resulted from expanded chondrification in the presumptive joint space, suggesting a crucial role for FGF signaling in regulating the transition of condensed mesenchyme to cartilage and in defining the boundary of skeletal elements.

Gerodermia osteodysplastica and wrinkly skin syndrome: are they the same?

Gerodermia osteodysplastica (GO) is a connective tissue disorder characterized by premature aging, wrinkled, and lax skin with reduced elasticity which is more marked on the dorsum of the hands and feet associated with hyperextensible joints and osteoporosis. The wrinkly skin syndrome (WSS) is characterized by wrinkled skin over the dorsum of the hands, feet, and abdomen; hyperextensible joints, particularly of the hands; intrauterine growth retardation; postnatal failure to thrive; and mental and developmental delay. We report on five children from two consanguineous Arab families with features overlapping both GO and WSS. All five children had similar dysmorphic facial features consisting of broad and prominent forehead, hypotelorism with epicanthal folds, prominent bulbous nose, flat malar region, and large protruding ears. All had wrinkling of the skin more marked on the dorsum of the hands, feet, and abdomen; hyperextensibility of the joints, particularly of the hands; and aged appearance. Intrauterine growth retardation, subsequent failure to thrive, developmental delay, and variable degree of osteoporosis was also present in all of them. The older three children developed progressive prognathism. We suggest that GO and WSS could represent variable manifestation of the same disorder.