Camptodactyly-Arthropathy-Coxa Vara-Pericarditis Syndrome Caused by Truncating Mutations in the

Introduction: Camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome is an autosomal recessive condition characterized by early-onset camptodactyly, noninflammatory arthropathy, coxa vara deformity, and, rarely, pericardial effusion. The disease gene has been assigned to human chromosome regions 1q25-q31, and truncating mutations have been identified in the Methods: A literature review was performed with the findings in patients in terms of CACP syndrome. Also, whole-exome sequencing was performed for all cases. Segregation analyses of the detected variants were performed according to the possibilities. Results: We present 3 Turkish patients with CACP syndrome mimicking juvenile idiopathic arthritis (JIA). All patients were exposed to biologic therapy due to recalcitrant JIA. We have detected two pathogenic PRG4 variants. Case 3 had a novel pathogenic PRG4 variant not reported for the CACP syndrome so far. These two variants cause premature truncation of the protein. A deletion was detected in case 1 in the homozygous state in the Conclusion: In the current study, we report three pathogenic PRG4 variants including a novel mutation. We consider that a detailed anamnesis, including kinship and meticulous physical examination of camptodactyly in the absence of inflammatory response, may reveal CACP syndrome masquerading as JIA. The