Clinical, radiographic, and genetic diagnosis of progressive pseudorheumatoid dysplasia in a patient with severe polyarthropathy

[Bilateral total hip arthroplasty in a 15-year-old patient with progressive pseudorheumatoid dysplasia. Case report and literature review]

Progressive pseudorheumatoid dysplasia (PPD) is an autosomal recessive hereditary disease of very low prevalence. It is characterized by the affection of multiple joints, generating arthrosis and progressive deformities from a very young age, which significantly affect the quality of life of patients. Its diagnosis is only confirmed by genetic testing, and no specific pharmacological treatment is still available. In the case of hip involvement, one treatment option is arthroplasty. In this case report, we present a 15-year-old boy with bilateral coxarthrosis secondary to PPD who underwent bilateral total hip arthroplasty in two stages. We highlight the characteristics of this rare entity, the intraoperative findings, the functional outcomes, and the impact on quality of life.

Progressive Pseudorheumatoid Dysplasia of Childhood (PPRD)-A Case Series with Recurrent c.740_741del Variant

Progressive pseudorheumatoid dysplasia (PPRD) is an autosomal recessive arthropathy, affecting school-aged children. It is characterized by progressive degeneration of the articular cartilage. The majority of the pathogenic variations are found in exon 2, exon 4, and exon 5 of the putative gene, CCN6 (WISP3). Three unrelated individuals with clinical diagnosis of PPD were included in this study. Detailed clinicoradiological evaluation was attempted with brief literature review. Exome sequencing was performed in all three cases. All the pathogenic variations detected in our cohort were located in exons 2 and 4 of WISP3 gene. Though the clinicoradiological features are already well described, this study in north India highlights the occurrence of a recurring pathogenic variant. The c.740_741del variant was a recurrent pathogenic variant seen in all three patients in this cohort. This may be a common pathogenic variant in the North Indian population; however, a larger cohort needs to be studied before drawing final conclusions. A proper molecular diagnosis is a must to end the diagnostic odyssey, safeguarding patients with PPRD from unnecessary use of drugs like corticosteroids.

Clinical and molecular characterization in a cohort of patients with progressive pseudorheumatoid dysplasia

Progressive pseudorheumatoid dysplasia (PPRD), a rare autosomal recessive syndrome, is a type of skeletal dysplasia associated with pain, stiffness, swelling of multiple joints, and the absence of destructive changes. PPRD occurs due to loss of function pathogenic variants in WISP3 (CCN6) gene, located on chromosome 6q22. In this study, 23 unrelated Egyptian PPRD patients were clinically diagnosed based on medical history, physical and radiological examinations, and laboratory investigations. Sequencing of the whole WISP3 (CCN6) exons and introns boundaries was carried out for all patients. A total of 11 different sequence variations were identified in the WISP3 (CCN6) gene, five of them were new pathogenic variants: the NM_003880.3: c.80T>A (p.L27*), c.161delG (p.C54fs*12), c.737T>C (p.Leu246Pro), c.347-1G>A (IVS3-1G>A), and c.376C>T (p.Q126*). The results of this study expand the spectrum of WISP3 (CCN6) pathogenic variants associated with PPRD. Clinical and genetic analysis is important for proper genetic counseling to curb this rare disorder in the families.

Mesenchymal stromal cells from a progressive pseudorheumatoid dysplasia patient show altered osteogenic differentiation

Background

Progressive pseudorheumatoid dysplasia (PPRD) is a rare autosomal recessive non-inflammatory skeletal disease with childhood onset and is characterized by a progressive chondropathy in multiple joints, and skeletal abnormalities. To date, the etiopathological relationship between biological modification occurring in PPRD and genetic mutation remains an open issue, partially due to the limited availability of biological samples obtained from PPRD patients for experimental studies.

Case presentation

We describe the clinical features of a PPRD patient and experimental results obtained from the biological characterization of PPRD mesenchymal stromal cells (MSCs) and osteoblasts (OBs) compared to normal cell populations. Phenotypic profile modifications were found in PPRD compared to normal subjects, essentially ascribed to decreased expression of CD146, osteocalcin (OC) and bone sialoprotein in PPRD MSCs and enhanced CD146, OC and collagen type I expression in PPRD OBs. Gene expression of Dickkopf-1, a master inhibitor of WNT signaling, was remarkably increased in PPRD MSCs compared to normal expression range, whereas PPRD OBs essentially exhibited higher OC gene expression levels. PPRD MSCs failed to efficiently differentiate into mature OBs, so showing a greatly impaired osteogenic potential.

Conclusions

Since all regenerative processes require stem cell reservoirs, compromised functionality of MSCs may lead to an imbalance in bone homeostasis, suggesting a potential role of MSCs in the pathological mechanisms of PPRD caused by WNT1-inducible signaling pathway protein-3 (WISP3) mutations. In consideration of the lack of compounds with proven efficacy in such a rare disease, these data might contribute to better identify new specific and effective therapeutic approaches.

Progressive pseudorheumatoid dysplasia: A rare entity mimicking juvenile idiopathic arthritis

Progressive pseudorheumatoid dysplasia can be confused with juvenile idiopathic arthritis. Treatment is mainly symptomatic and the prescription of immunosupressive agents is unnecessary. Surgery may be indicated at advanced stages of the disease.

Progressive pseudorheumatoid dysplasia: a case series report

rogressive pseudorheumatoid dysplasia (PPRD) is a rare autosomal-recessive, noninflammatory arthropathy. Several cases have been reported worldwide; however, diagnosis remains challenging. Three unrelated children with PPRD were retrospectively studied. All three patients in this study were initially misdiagnosed. The misdiagnoses included juvenile rheumatoid arthritis, myodystrophy and idiopathic short stature. The time from the onset of symptoms to a definitive diagnosis was 3 to 8 years. Clinical signs and radiological phenotypes were analyzed carefully, and they were all consistent with the characteristics of PPRD and noninflammatory polyarticular enlargement. The small joints of both the hands and lower limbs are the most affected. The imaging findings of the patients were flat vertebrae with beak- or bullet-like changes in front of the cone and peripheral metaphysis widening. DNA samples obtained from the family were sequenced to identify the causal gene using whole-exome sequencing (WES). Four Wnt1-inducible signaling pathway protein 3 (WISP3) mutations were verified. c.271delC was not reported previously. The other three mutations, namely, c.136C>T (p. Gln46*), c.667T>G (p. Cys223Gly) and c.589+2T>C, were previously identified. All three patients had a long journey to diagnosis. Early genetic diagnosis can help prevent unnecessary treatments and procedures in patients. Growth hormone is not a good choice for treatment.

Progressive pseudorheumatoid dysplasia: a report of three cases and a review of radiographic and magnetic resonance imaging findings

Progressive pseudorheumatoid dysplasia (PPD) is a rare disorder of postnatal skeletal and cartilage development that often presents with similar clinical findings to juvenile idiopathic arthritis. Patients with PPD display findings of progressive cartilage loss and secondary osteoarthritis over serial imaging studies and have an absence of elevation of inflammatory markers. Awareness of the imaging features of PPD on radiographs and magnetic resonance imaging (MRI) may be important for early diagnosis and surveillance of the disease.

Progressive pseudorheumatoid dysplasia: a rare childhood disease

Progressive pseudorheumatoid dysplasia (PPRD) is a genetic bone disorder characterised by the progressive degeneration of articular cartilage that leads to pain, stiffness and joint enlargement. As PPRD is a rare disease, available literature is mainly represented by single case reports and only a few larger case series. Our aim is to review the literature concerning clinical, laboratory and radiological features of PPRD. PPRD is due to a mutation in Wnt1-inducible signalling protein 3 (WISP3) gene, which encodes a signalling factor involved in cartilage homeostasis. The disease onset in childhood and skeletal changes progresses over time leading to significant disability. PPRD is a rare condition that should be suspected if a child develops symmetrical polyarticular involvement without systemic inflammation, knobbly interphalangeal joints of the hands, and gait abnormalities. A full skeletal survey, or at least a lateral radiograph of the spine, can direct towards a correct diagnosis that can be confirmed molecularly. More than 70 WISP3 mutations have so far been reported. Genetic testing should start with the study of genomic DNA extracted from blood leucocytes, but intronic mutations in WISP3 causing splicing aberrations can only be detected by analysing WISP3 mRNA, which can be extracted from cultured skin fibroblasts. A skin biopsy is, therefore, indicated in patients with typical PPRD findings and negative mutation screening of genomic DNA.

Ilizarov technique in an adolescent patient with progressive pseudorheumatoid dysplasia: A case report

RATIONALE

Progressive pseudorheumatoid dysplasia (PPD) is a rare autosomal recessive inherited disease that causes severe systemic joint deformity and articular dysfunction in young patients.

PATIENT CONCERNS

Ilizarov technique treatment in PPD patients has never been reported before.

DIAGNOSES

A 17-year-old male patient presented with a 10-year history of polyarthritis and 4-year history of progressive hip and knee pain and stiffness. Genetic testing for the WISP3 gene was done and showed compound heterozygous mutations: NM_198239.1 (WISP3):c.1064_1065dupGT (p.Gln356ValfsTer33) and NM_198239.1 (WISP3):c.643+2T > C.

INTERVENTIONS

Taking his young age into consideration, the Ilizarov external fixation technique was adopted for the treatment of the deformity in knees.

OUTCOMES

One year after the operation, the improvement of joint deformity was satisfactory.

LESSONS

The Ilizarov technique is economical and less invasive, and most importantly, it can delay the possible arthroplasty. It gives young PPD patients with arthropathy an alternative treatment.

WISP3 mutation associated with pseudorheumatoid dysplasia

Progressive pseudorheumatoid dysplasia (PPD) is a skeletal dysplasia characterized by predominant involvement of articular cartilage with progressive joint stiffness. Here we report genetic characterization of a consanguineous family segregating an uncharacterized from of skeletal dysplasia. Whole-exome sequencing of four affected siblings and their parents identified a loss-of-function homozygous mutation in the WISP3 gene, leading to diagnosis of PPD in the affected individuals. The identified variant (Chr6: 112382301; WISP3:c.156C>A p.Cys52*) is rare and predicted to cause premature termination of the WISP3 protein.

Progressive Pseudorheumatoid Dysplasia Misdiagnosed as Seronegative Juvenile Idiopathic Arthritis

Background

Progressive pseudorheumatoid dysplasia (PPD) is a rare spondylo-epi-metaphyseal dysplasia (SEMD). It can be confused with juvenile idiopathic arthritis (JIA), both clinically and radiologically. Early detection and diagnosis of PPD are important in helping to relieve the pain and disability associated with this disease and in avoiding unnecessary investigations and anti-rheumatic interventions.

Case Details

We report the case of a 15-year-old girl with PPD who was misdiagnosed with JIA.

Conclusion

In conclusion, PPD is a rare SEMD and can be confused with JIA, both clinically and radiologically. Early detection and diagnosis of PPD are important in helping to relieve the pain and disability associated with this disease and in avoiding unnecessary investigations and anti-rheumatic interventions.

WISP3 mutational analysis in Indian patients diagnosed with progressive pseudorheumatoid dysplasia and report of a novel mutation at p.Y198

Objectives

To determine the pattern of mutations of the WISP3 gene in clinically identified progressive pseudorheumatoid dysplasia (PPD) in an Indian population.

Patients and Methods

A total of 15 patients with clinical features of PPD were enrolled in this study. Genomic DNA was isolated and polymerase chain reaction performed to amplify the WISP3 gene. Screening for mutations was done by conformation-sensitive gel electrophoresis, beginning with the fifth exon and subsequently proceeding to the remaining exons. Sanger sequencing was performed for both forward and reverse strands to confirm the mutations.

Results

In all, two of the 15 patients had compound heterozygous mutations: one a nonsense mutation c.156C>A (p.C52*) in exon 2, and the other a missense mutation c.677G>T (p.G226V) in exon 4. All others were homozygous, with three bearing a nonsense mutation c.156C>A (p.C52*) in exon 2, three a missense mutation c.233G>A (p.C78Y) in exon 2, five a missense mutation c.1010G>A (p.C337Y) in exon 5, one a nonsense mutation c.348C>A (p.Y116*) in exon 3, and one with a novel deletion mutation c.593_597delATAGA (p.Y198*) in exon 4.

Conclusion

We identified a novel mutation c.593_597delATAGA (p.Y198*) in the fourth exon of the WISP3 gene. We also confirmed c.1010G>A as one of the common mutations in an Indian population with progressive pseudorheumatoid dysplasia.

Cite this article: V. Madhuri, M. Santhanam, K. Rajagopal, L. K. Sugumar, V. Balaji. WISP3 mutational analysis in Indian patients diagnosed with progressive pseudorheumatoid dysplasia and report of a novel mutation at p.Y198* Bone Joint Res 2016;5:301–306. DOI: 10.1302/2046-3758.57.2000520.

An Unusual Coexistence of Progressive Pseudorheumatoid Dysplasia and Relapsing Polychondritis

Progressive pseudorheumatoid dysplasia is a rare hereditary skeletal disease characterized by bone and cartilage dysplasia, progressive arthropathy without sign of systemic or synovial inflammation. Relapsing polychondritis (RP) is a rare autoimmune disease associated with inflammation in cartilaginous and other proteoglycan rich structures. An associated autoimmune and/or hematologic disorder is seen in over 30% of patients with RP. To our knowledge, coexistence of progressive pseudorheumatoid dysplasia and RP has not been previously reported. In this article, we describe an unusual case of coexisting progressive pseudorheumatoid dysplasia with RP. Physicians should be aware of this possible association.

Dysfunction of collagen synthesis and secretion in chondrocytes induced by wisp3 mutation

Wisp3 gene mutation was shown to cause spondyloepiphyseal dysplasia tarda with progressive arthropathy (SRDT-PA), but the underlying mechanism is not clear. To clarify this mechanism, we constructed the wild and mutated Wisp3 expression vectors and transfected into human chondrocytes lines C-20/A4; Wisp3 proteins subcellular localization, cell proliferation, cell apoptosis, and Wisp3-mediated gene expression were determined, and dynamic secretion of collagen in transfected chondrocytes was analyzed by (14)C-proline incorporation experiment. Mutated Wisp3 protein increased proliferation activity, decreased apoptosis of C-20/A4 cells, and aggregated abnormally in cytoplasm. Expression of collagen II was also downregulated in C-20/A4 cells transfected with mutated Wisp3. Wild type Wisp3 transfection increased intracellular collagen content and extracellular collagen secretion, but the mutated Wisp3 lost this function, and the peak phase of collagen secretion was delayed in mutated Wisp3 transfected cells. Thus abnormal protein distribution, cell proliferation, collagen synthesis, and secretion in Wisp3 mutated chondrocytes might contribute to the pathogenesis of SEDT-PA.

Pseudorheumatoid dysplasia. A rare genetic disorder simulating juvenile idiopathic arthritis

We present the case of a teenage patient with progressive pseudorheumatoid dysplasia, an autosomal recessive disorder that may be initially misdiagnosed as juvenile idiopathic arthritis.

Novel and recurrent mutations of WISP3 in two Chinese families with progressive pseudorheumatoid dysplasia

Background

The WNT1-inducible signaling pathway protein 3 (WISP3), which belongs to the CCN (cysteine-rich protein 61, connective tissue growth factor, nephroblastoma overexpressed) family, is a secreted cysteine-rich matricellular protein that is involved in chondrogenesis, osteogenesis and tumorigenesis. WISP3 gene mutations are associated with progressive pseudorheumatoid dysplasia (PPD, OMIM208230), an autosomal recessive genetic disease that is characterized by the swelling of multiple joints and disproportionate dwarfism.

Methodology/Principal Findings

Four PPD patients from two unrelated Chinese families were recruited for this study. The clinical diagnosis was confirmed by medical history, physical examinations, laboratory results and radiological abnormalities. WISP3 mutations were detected by direct DNA sequence analysis. In total, four different mutations were identified, which consisted of two missense mutations, one deletion and one insertion that spanned exons 3, 5 and 6 of the WISP3 gene. One of the missense mutations (c.342T>G/p.C114W) and a seven-base pair frameshift deletion (c.716_722del/p.E239fs*16) were novel. The other missense mutation (c.1000T>C/p. S334P) and the insertion mutation (c.866_867insA/p.Q289fs*31) had previously been identified in Chinese patients. All four cases had a compound heterozygous status, and their parents were heterozygous carriers of these mutations.

Conclusions/Significance

The results of our study expand the spectrum of WISP3 mutations that are associated with PPD and further elucidate the function of WISP3.

Unusual unilateral presentation of pachydermodactyly: a case report

Pachydermodactyly is a rare digital fibromatosis characterized by asymptomatic fusiform soft-tissue swellings of the proximal interphalangeal joints of the hands. It usually affects healthy adolescent males with a negative family history. As a rule, clinical presentation of the disease is bilateral and symmetrical enlargement of the joints. So it can be misdiagnosed with inflammatory rheumatic diseases, especially with juvenile chronic arthritis. A prompt clinical diagnosis of the disease would prevent inappropriate treatment with immunosuppressive agents or steroids and unnecessary expensive diagnostic procedures such as biopsy or magnetic resonance imaging. Once diagnosed, patients should be advised in order to avoid repetitive traumas of the hands, rubbing and cracking of the fingers, obsessive-compulsive use of computer and video games. The joint outcome is always benign. Here, we report a case of pachydermodactyly differs from the typical clinical picture of pachydermodactyly in the unilateral distribution of the lesions.

A homozygous recurring mutation in WISP3 causing progressive pseudorheumatoid arthropathy

WISP3 is a member of the CCN (for CTGF, CYR61, and NOV) gene family, which encodes cysteine-rich secreted proteins with roles in cell growth and differentiation. Mutations in the WISP3 gene are associated with the autosomal recessive skeletal disorder, also known as progressive pseudorheumatoid arthropathy of childhood (PPAC). We diagnosed three siblings from a non-consanguineous family with PPAC. The patients were asymptomatic in early childhood. Signs and symptoms of disease that include progressive joint stiffness, swelling of the finger joints, and osteopenia, and slow linear growth developed between 2 and 8 years of age. PCR amplification and direct sequencing of the WISP3 gene revealed a homozygous mutation at nucleotide 156 of the WISP3 gene, resulting in a Cys52-to-ter substitution. This mutation has previously been reported in French, Italian, and Arab families. Interestingly, the C52X mutation was found to be associated with a c.248G-->A (G83E) variation, suggesting the existence of a founder effect. By contrast, the presence of the same aberration in three different ethnic groups could imply that this particular site is prone to mutation. Basal fasting concentrations of growth hormone, insulin-like growth factor-1, and insulin-like growth factor binding protein-3, as well as glucose and insulin levels revealed no aberrations. In conclusion, consideration of this rare disease that causes significant morbidity with short stature, osteopenia and arthritic complaints would prevent unnecessary examinations and treatment attempts. Testing for this specific mutation in suspected cases could provide a rapid and definitive diagnosis.

Identification of novel mutations in WISP3 gene in two unrelated Chinese families with progressive pseudorheumatoid dysplasia

INTRODUCTION

Progressive pseudorheumatoid dysplasia (PPD) is an autosomal recessive genetic disease and it has been reported that PPD is caused by mutations of the Wnt1-inducible signaling pathway protein 3 (WISP3) gene which is located on chromosome 6q22. Up to date, 16 different mutations in the WISP3 have been identified in patients with PPD in different countries previously, but only two mutations in exon 5 were previously identified from Asian origin. Our study aimed to characterize the clinical manifestations and features of PPD and screen the mutations of the disease causing WISP3, and try to elucidate the molecular pathogenesis of PPD.

MATERIALS AND METHODS

Altogether, 153 persons, including 4 affected individuals, 49 unaffected individuals from two unrelated Chinese families, and 100 healthy donors were recruited and genomic DNA was extracted. PPD was diagnosed based on the clinical manifestations, physical examination, characteristics of their bones on X-ray and laboratory results. All 5 exons and their exon-intron boundaries of the WISP3 gene were amplified by polymerase chain reaction (PCR) and sequenced directly.

RESULTS

In family 1, we identified that the proband (IV4) carried a novel non-sense mutation (G46X) which consisted of a homozygous C to T transition at c.8004 in exon 3. This mutation changed codon CAG to TAG and resulted in a subsequent change of the glutamine codon to stop codon and truncation at p. 46. In family 2, a novel missense mutation (C114Y) was found in the three patients (IV6, IV7, IV8), namely, a homozygous G to A transition at c.8209 in exon 3, which resulted in a cysteine (TGT) to tyrosine (TAT) substitution at p.114. Neither G46X nor C114Y was found in 100 normal controls. Meanwhile, we found that these patients had some different phenotypes, compared with the affected individuals with PPD from cases reported previously.

CONCLUSIONS

Our study suggests that the novel G46X and C114Y mutations in exon 3 in WISP3 gene are responsible for PPD in Chinese patients. Furthermore, many heterozygous carriers (c.8004C>T and c.8209G>A) are found in the two families, suggesting the existence of a founder effect in the locality where they live, respectively.

Role of CCN, a vertebrate specific gene family, in development

The CCN family of genes constitutes six members of small secreted cysteine rich proteins, which exists only in vertebrates. The major members of CCN are CCN1 (Cyr61), CCN2 (CTGF), and CCN3 (Nov). CCN4, CCN5, and CCN6 were formerly reported to be in the Wisp family, but they are now integrated into CCN due to the resemblance of their four principal modules: insulin like growth factor binding protein, von Willebrand factor type C, thrombospondin type 1, and carboxy-terminal domain. CCNs show a wide and highly variable expression pattern in adult and in embryonic tissues, but most studies have focused on their principal role in osteo/chondrogenesis and vasculo/angiogenesis from the aspect of migration, growth, and differentiation of mesenchymal cells. CCN proteins simultaneously integrate and modulate the signals of integrins, bone morphogenetic protein, vascular endothelial growth factor, Wnt, and Notch by direct binding. However, the priority in the use of the signals is different depending on the cell status. Even the equivalent counterparts show a difference in signal usage among species. It may be that the evolution of the CCN family continues to keep pace with vertebrate evolution itself.

Spondyloepiphyseal dysplasia tarda: four cases from two families

Spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA) is an autosomal recessively inherited skeletal dysplasia. We present four patients (three patients-a brother and a sister and their third cousin-in a family and one patient in another family) with SEDT-PA. All patients had short stature and stubby hands and feet. Their radiographs revealed typical changes for SEDT-PA including platyspondyly, severe osteopenia and dysplastic bone changes. Physical therapy and exercises were performed to all patients in order to decrease in pain and increase or at least maintain joint motion and mobility. Symptomatic relief was achieved in all patients for about a couple of months. The major clinical importance of this rather rare disorder is its similarity to juvenile idiopathic arthritis which has rather different treatment protocol.

The CCN family member Wisp3, mutant in progressive pseudorheumatoid dysplasia, modulates BMP and Wnt signaling

In humans, loss-of-function mutations in the gene encoding Wnt1 inducible signaling pathway protein 3 (WISP3) cause the autosomal-recessive skeletal disorder progressive pseudorheumatoid dysplasia (PPD). However, in mice there is no apparent phenotype caused by Wisp3 deficiency or overexpression. Consequently, the in vivo activities of Wisp3 have remained elusive. We cloned the zebrafish ortholog of Wisp3 and investigated its biologic activity in vivo using gain-of-function and loss-of-function approaches. Overexpression of zebrafish Wisp3 protein inhibited bone morphogenetic protein (BMP) and Wnt signaling in developing zebrafish. Conditioned medium-containing zebrafish and human Wisp3 also inhibited BMP and Wnt signaling in mammalian cells by binding to BMP ligand and to the Wnt coreceptors low-density lipoprotein receptor-related protein 6 (LRP6) and Frizzled, respectively. Wisp3 proteins containing disease-causing amino acid substitutions found in patients with PPD had reduced activity in these assays. Morpholino-mediated inhibition of zebrafish Wisp3 protein expression in developing zebrafish affected pharyngeal cartilage size and shape. These data provide a biologic assay for Wisp3, reveal a role for Wisp3 during zebrafish cartilage development, and suggest that dysregulation of BMP and/or Wnt signaling contributes to cartilage failure in humans with PPD.

Progressive pseudorheumatoid dysplasia: Three cases in one family

Progressive pseudorheumatoid dysplasia is an inherited skeletal dysplasia with autosomal recessive transmission. Radiographs of the spine show abnormalities similar to those seen in spondyloepiphyseal dysplasia tarda. The clinical presentation, but not the imaging study findings, suggest juvenile idiopathic arthritis. We report 3 cases of progressive pseudorheumatoid dysplasia in the same family.

CASE-REPORTS

A 4-year-old girl had been receiving follow-up for 3 years for seronegative, polyarticular juvenile idiopathic arthritis progressing by flares and remissions. The disease was unresponsive to anti-inflammatory medications. Findings at admission included inflammatory joint pain, joint swelling, range-of-motion limitation, and joint deformities in the hands, wrists, ankles, and knees. The hips were normal. Normal values were found for the erythrocyte sedimentation rate and C-reactive protein level. Synovial fluid removed from one of the knees exhibited mechanical properties. Plain radiographs of the hands and forefeet showed no evidence of joint destruction. Bilateral hip dysplasia was noted on a radiograph of the pelvis. The diagnosis of juvenile idiopathic arthritis was reconsidered. A study of the family identified two similar cases, in a brother and paternal uncle. The brother, who was 14 years old, had similar manifestations without laboratory evidence of inflammation; radiographs disclosed dysplasia of the hips and metacarpophalangeal epiphyses. Manifestations in a paternal uncle consisted of spinal stiffness, thoracic kyphosis, and motion-range limitation at the hips; radiographs showed normal sacroiliac joints and bilateral hip dysplasia. A diagnosis of progressive pseudorheumatoid dysplasia with polyarticular involvement was given.

DISCUSSION

Progressive pseudorheumatoid dysplasia is an autosomal recessive disease characterized by abnormal cartilage homeostasis. It should be included among the differential diagnoses of juvenile idiopathic arthritis.

Cellular and molecular responses in progressive pseudorheumatoid dysplasia articular cartilage associated with compound heterozygous WISP3 gene mutation

Progressive pseudorheumatoid dysplasia (PPD) is characterized by continuous degeneration and loss of articular cartilage, which has been attributed to mutations in the gene encoding WISP3. We collected a PPD family and analyzed their WISP3 genes mutation. Articular chondrocytes (ACs) were purified from the femurs of a PPD patient after hip replacement surgery. Cell growth, proliferation, and viability were examined. Gene expression profiling and analyses of matrix metalloproteinases (MMP)-1, -3, and -13 proteins were carried out using cDNA differential microarrays, real-time reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot analysis. We found that two probands carried a deletion (840delT) mutation in maternal allele, which leads to truncated WISP3 protein missing 43 residues in C terminus; and a 1000T>C substitution in paternal allele, which was also passed on to four other members in the PPD kindred. PPD ACs were heterogeneous in size with an enhanced rate of cell proliferation and viability compared with the normal ACs. MMP-1, -3, and -13 mRNA expressions were dereased in PPD ACs. MMP-1, -3, and -13 protein levels, however, were increased in cell lysates from PPD ACs, but markedly decreased in the supernatants from cultured ACs. WISP3 mRNA expression in PPD ACs was also decreased. Our results show, for the first time, a compound heterozygous mutation of WISP3 and a series of cellular and molecular changes disturbing the endochondral ossification in this PPD patient.

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

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

A case of progressive pseudorheumatoid arthropathy of 'childhood' with the diagnosis delayed to the fifth decade

Progressive pseudorheumatoid arthropathy of childhood (PPAC) is a rare single gene disorder which is frequently misdiagnosed as juvenile rheumatoid arthritis. It is characterised with arthralgia, joint contractures, bony swelling of metacarpophalangeal and interphalangeal joints and platyspondyly. Clinical and laboratory signs of joint inflammation such as synovitis, a high erythrocyte sedimentation rate and an elevated C-reactive protein level are usually absent. Although the disease begins early in life (usually between 3 and 8 years of age), the diagnosis may be delayed. In the present case report, we describe a male patient diagnosed with PPAC at the age of 46 years, although he had been exhibiting the typical radiological and clinical features of the disease since the age of 7 years.

Clinical and radiological diagnosis of progressive pseudorheumatoid dysplasia in two sisters with severe polyarthropathy

The aim of this case report is to describe unusual cases of progressive pseudorheumatoid dysplasia (PPD) affecting the axial skeleton and peripheral joints and to stress the importance of examining the entire skeleton for definite diagnosis and the importance of rehabilitation interventions. PPD is a rare familial disease characterized by generalized bone-cartilage dysplasia, progressive arthropathy, and platyspondyly. PPD presents as spondyloepiphyseal dysplasia (SED) tarda with progressive arthropathy and progressive pseudorheumatoid arthritis of childhood and is described as a specific autosomal recessive subtype of SED. Two sisters, 18 and 16 years old, with low back pain and polyarthritis are presented. Radiographic and magnetic resonance imaging of the cases revealed typical features characteristic for PPD-like platyspondyly, multiple intravertebral herniations, changes in metaphyses and epiphysis, and mega os trigonum. Consequently, PPD is a rare disease of childhood and should be kept in mind in the differential diagnosis of juvenile idiopathic arthritis to prevent delayed diagnosis and to begin rehabilitation interventions early. It is essential to carefully examine the entire body, particularly the axial skeleton, and to perform radiological evaluation of the spine. These illustrative cases serve to remind physicians to examine the entire skeleton and not to concentrate only on "branches" but also on the "trunk."

WISP3, the gene responsible for the human skeletal disease progressive pseudorheumatoid dysplasia, is not essential for skeletal function in mice

In humans, loss-of-function mutations in WISP3 cause the autosomal recessive skeletal disease progressive pseudorheumatoid dysplasia (PPD) (Online Mendelian Inheritance in Man database number 208230). WISP3 encodes Wnt1-inducible signaling protein 3, a cysteine-rich, multidomain, secreted protein, whose paralogous CCN (connective tissue growth factor/cysteine-rich protein 61/nephroblastoma overexpressed) family members have been implicated in diverse biologic processes including skeletal, vascular, and neural development. To understand the role of WISP3 in the skeleton, we targeted the Wisp3 gene in mice by creating a mutant allele comparable to that which causes human disease. We also created transgenic mice that overexpress human WISP3 in cartilage. Surprisingly, homozygous Wisp3 mutant mice appear normal and do not recapitulate any of the morphological, radiographic, or histological abnormalities seen in patients with PPD. Mice that overexpress WISP3 are also normal. We conclude, that in contrast to humans, Wisp3 is not an essential participant during skeletal growth or homeostasis in mice.

Molecular study ofWISP3 in nine families originating from the Middle-East and presenting with progressive pseudorheumatoid dysplasia: Identification of two novel mutations, and description of a founder effect

Progressive pseudorheumatoid dysplasia (PPD) is a rare autosomal recessive syndrome characterized by the presence of spondyloepiphyseal dysplasia associated with pain, stiffness, and swelling of multiple joints, osteoporosis, and the absence of destructive bone changes. The disorder is caused by mutations of the WISP3 gene located on chromosome 6q22. We hereby report the molecular study of the WISP3 gene in nine unrelated consanguineous families originating from the Middle-East: three from Lebanon, five from Syria, and one from Palestinian Bedouin descent, all affected with PPD. Five different sequence variations were identified in the WISP3 gene, two of them being new mutations: the c.589G --> C transversion at codon 197, responsible for a splicing defect (A197fsX201); and the c.536_537delGT deletion (C179fsX), both in exon 3. In all other families, the affected patients were homozygous for a previously described nonsense mutation, namely c.156C --> A (C52X). Interestingly, in the latter families, the C52X mutation was always found associated with a novel c.248G --> A (G83E) variation, suggesting the existence of a founder effect.