PRG4 and Camptodactyly: Camptodactyly arthropathy coxa vara pericarditis syndrome (CACP) is an autosomal recessive condition, caused by pathogenic variants in PRG4 and characterized by the association of congenital or early onset camptodactyly, non-inflammatory arthropathy, progressive coxa vara deformity and/or pericardial effusion [12, 13].