Bone Abstracts

Objectives: To describe the clinical, laboratory, radiological and genetic findings of camptodactyly-arthropathycoxa vara-pericarditis (CACP) syndrome in Saudi children.

Methods: Medical records of all children with CACP syndrome seen between June 1990 and June 2012 at KFSHRC-Riyadh were reviewed. The data included: gender, age at disease onset, referral diagnosis, clinical and radiological features and molecular genetic studies as well as functional status at the last follow-up visit.

Results: Twenty-two patients (15 boys) with mean age at diagnosis of 3.7 years were identified. Juvenile idiopathic arthritis (JIA) was the referral diagnosis in the majority. Camptodactyly and large joints arthropathy were present in all cases. Camptodactyly was observed in the neonatal period in all patients, while other joint involvement was observed through the 1st year of life. Two children had evidence of pericarditis. All patients had normal inflammatory markers and negative rheumatoid factor. Radiological findings included coxa vara with short femoral neck and flat, irregular femoral heads and intra-osseous cysts. Synovial biopsy from three patients revealed proliferating synovial epithelium with moderate fibro-collagenous densities and multinucleated giant cells. A locus responsible for causing CACP syndrome has been reported previously in eight patients of our cohort; it has been assigned to 1q25–q31. Furthermore; in seven newly diagnosed patients from four unrelated families; five novel mutations were found. No genotype/phenotype association was observed. All patients referred to us while they were on NSAIDs, ten patients used prednisone and methotrexate; and two patients treated with etanercept. Treatment in all patients was ineffective apart from mild pain relief.

Conclusion: CACP syndrome is not uncommon disorder in Saudi Arabia. Pericarditis is rarely seen in our patients. Our data suggests that CACP syndrome may be easily confused with JIA, causing a delay in diagnosis and probably unnecessary treatment with anti-rheumatic drugs including biologic agents.