Congenital contractural deformities of the fingers and arthropathy

A novel mutation in PRG4 gene underlying camptodactyly-arthropathy-coxa vara-pericarditis syndrome with the possible expansion of the phenotype to include congenital cataract

BACKGROUND

Camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is a clinically heterogenous congenital disorder caused by mutations in proteoglycan 4 (PRG4), a chondroitin sulfate proteoglycan that acts as a lubricant for the cartilage surface. Although CACP is a rare genetic disorder, several cases were described in the literature from ethnically different populations including Caucasian, Egyptian, Saudi Arabian, Pakistani, and Korean. We report CACP for the first time in United Arab Emirates.

METHODS

Direct sequencing of all the coding exons and splice sites of the PRG4 gene was performed for all the members of the affected family.

RESULTS

The studied family is consanguineous and has multiple affected members from different branches showing congenital camptodactyly with arthropathy, the hallmarks of CACP. All the affected family members lack pericarditis, but one of them was born with cataract, which has never been documented in any of the previously reported cases of CACP. Molecular analysis revealed a novel homozygous insertion of a cytosine nucleotide (c.1320dupC) in the highly repetitive portion of the coding sequence of the PRG4 gene. The detected mutation caused a frameshift in the cDNA sequence and created a premature termination codon (p.P440fsX197), which is likely to result in a nonfunctional protein.

CONCLUSION

We report a family from the United Arab Emirates with typical features of CACP in whom one of the children had in addition, a bilateral congenital cataract. We also report the identification of a novel null mutation in PRG4 confirming the genetic homogeneity of CACP.

Synovial pathology in camptodactyly-arthropathy-coxa vara-pericarditis syndrome

At least 25 families with camptodactyly-arthropathy-coxa vara-pericarditis (CACP syndrome) have been reported, with descriptions of a distinctive synovial pathology based largely on light microscopy. Although described as "proliferative," with numerous multinucleated giant cells, the natures of proliferating cells and giant cells have not been determined. To clarify the pathogenesis of this disorder, we studied 3 patients who had CACP syndrome and underwent synovial biopsy. Cells in the biopsies were studied by immunohistochemistry and electron microscopy. Giant cells were identified as macrophage in origin based on CD68 expression and electron microscopic features of macrophages. Most cells in the synovium were CD68 positive, in keeping with macrophages. The degree of proliferation in synovial biopsies was estimated by MIB1 immunostaining, which showed that up to 30% of cells were cycling compared with fewer than 10% in control synovial biopsies. None of the giant cells was cycling. By double immunostaining, proliferating cells were determined to be fibroblastic synoviocytes rather than macrophages. Thus the proliferative synovitis in this CACP syndrome can be more accurately thought of as hypercellularity by infiltrating macrophages with a contribution by proliferating fibroblastic synoviocytes. The synoviocyte proliferation is likely a response to the underlying genetic mutations involving the proteoglycan-4 (or CACP) gene. The encoded protein normally acts as a lubricant and possibly controls cell proliferation. Loss of one or another of these functions may be a possible mechanism that leads to synoviocyte proliferation in this disease, but the exact pathophysiology leading to this change requires further study.

Camptodactyly, arthropathy, coxa vara, pericarditis (CACP)syndrome: a case report

The camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is characterized by congenital or early-onset camptodactyly, childhood-onset noninflammatory arthropathy associated with synovial hyperplasia. Some patients have progressive coxa vara deformity and/or noninflammatory pericardial effusion. CACP is inherited as an autosomal recessive mode and the disease gene is assigned to a 1.9-cM interval on human chromosome 1q25-31. We describe a 10-yr-old boy who has typical features of CACP without familial association.

Clinical variability and genetic homogeneity of the camptodactyly-arthropathy-coxa vara-pericarditis syndrome

The camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is an autosomal recessive condition characterized by the association of congenital or early onset camptodactyly and noninflammatory arthropathy with synovial hyperplasia. Progressive coxa vara deformity and/or noninflammatory pericardial or pleural effusions have been observed in some patients. Recently, the disease gene has been assigned to human chromosome region 1q25-q31, and truncating mutations have been identified in the megakaryocyte stimulating factor gene. Studying 12 patients from 8 unrelated families, we emphasized hip and spine involvement, particularly in the course of the disease as shown in a 58-year-old patient. Despite clinical variability, linkage studies support genetic homogeneity of the disease.

The camptodactyly-arthropathy-coxa vara-pericarditis syndrome: clinical features and genetic mapping to human chromosome 1

OBJECTIVE

To delineate the clinical features in patients with the autosomal recessive camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) and to determine the location of the involved gene.

METHODS

Eight affected individuals (ages 2-15 years) with CACP from 4 consanguineous kindreds were clinically evaluated. Four patients are newly described and 4 have been reported previously. Findings were compared with those in 21 other previously reported cases. DNA obtained from the 8 affected patients and their available siblings and parents was used in a genome-wide search for linkage.

RESULTS

Congenital camptodactyly and childhood-onset noninflammatory arthropathy were present in all affected patients. Seven patients developed bilateral coxa vara deformity, and 1 developed coxa magna with cystic erosions. Two of the patients also had symptoms or signs of pericarditis. A genome-wide search for linkage identified homozygosity for a series of genetic markers on human chromosome 1q in all affected patients. The marker D1S191 yielded a maximum logarithm of the odds ratio (LOD score) of 3.3 at theta = 0. The CACP gene lies within a 1.9-cM candidate interval defined by the markers D1S2107 and D1S222.

CONCLUSION

The principal features of the CACP syndrome are congenital or early-onset camptodactyly and childhood-onset noninflammatory arthropathy. Coxa vara deformity or other dysplasia associated with progressive hip disease may develop over time. Clinical pericarditis may also occur. A locus responsible for causing CACP syndrome is assigned to a 1.9-cM interval on human chromosome 1q25-31 by homozygosity mapping. This now facilitates the identification of the responsible gene and permits testing for locus homogeneity in other CACP kindreds.

Syndrome of camptodactyly, arthropathy and coxa vara (CAC syndrome)

Three Saudi children (two female, one male) are described who presented with familial arthropathy associated with congenital camptodactyly. This rare but recognized clinical entity has a variable clinical presentation and may be associated with pericarditis and coxa vara. Camptodactyly was observed in the neonatal period in all patients, while joint swelling was observed between the third and 11th month. Pericarditis was suspected in the referral hospital in one patient but was not subsequently confirmed at our institution, raising the possibility that pericarditis may be reversible. Radiological examination of the hips showed coxa vara with short femoral neck in all patients. Synovial biopsy in the three patients revealed proliferating synovial epithelium with moderate fibrocollagenous densities and multinucleated giant cells, occasional lymphocytes or neutrophils but no plasma cells were identified. This is the first series of this familial arthropathy with a triad of camptodactyly, arthropathy and coxa vara (CAC syndrome) in Saudi Arabia which is to be considered in patients where more than one family member has juvenile arthritis.

Radiological features in congenital camptodactyly, familial arthropathy and coxa vara syndrome

The association of congenital camptodactyly, familial arthropathy and coxa vara is a rare but recognized clinical entity. The radiological manifestations were reviewed in five patients. In the hips, coxa vara, short broad femoral necks and intraosseous cysts were demonstrated in all patients. Abnormal modeling of the acetabulum, increased joint space, effusion, small iliac wings and intraosseous herniation of fluid were found in four out of five patients. Somewhat flat, slightly irregular femoral heads were seen in three patients. In the knees, effusion was demonstrated in all five patients and thick cartilage in three. The elbow, wrist and ankle joints showed abnormal modeling with evidence or suspicion of intraarticular fluid in the majority of patients. Flexion deformities of the fingers were seen in all patients.