A novel mutation in the proteoglycan 4 gene causing CACP syndrome: two sisters report

Background Camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome, caused by biallelic pathogenic mutations in the proteoglycan 4 ( PRG4 ) gene, is characterized by early-onset camptodactyly, noninflammatory arthropathy, coxa vara deformity, and rarely, pericardial effusion. This syndrome can mimic juvenile idiopathic arthritis. CACP syndrome is caused by mutations in the proteoglycan 4 ( PRG4 ) gene. To date, only 36 pathogenic mutations have been reported in this gene, but none have been reported from Azerbaijan. Case presentation Herein, we report two siblings presented with chronic polyarthritis, had a prior diagnosis of juvenile idiopathic arthritis, but was subsequently diagnosed as CACP syndrome with novel mutation in the PRG4 gene. Conclusion Our report expands the knowledge of PRG4 mutations, which will aid in CACP patient counseling.