Camptodactyly-arthropathy-coxa vara-pericarditis syndrome: important differential for juvenile idiopathic arthritis.

Camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome is an inherited disorder characterized by congenital or early-onset flexion camptodactyly, childhood-onset of non-inflammatory arthropathy, often associated with non-inflammatory pericarditis or pericardial effusion and progressive coxa vara. The causative gene is located on chromosome band 1q25-31. This gene encodes for "proteoglycan-4" (PRG-4), which is a surface lubricant for joints and tendons. This syndrome has distinct radiological and histological features, which are important to recognize since it may clinically mimic juvenile idiopathic arthritis and mutation studies may not be easily available. We describe a case of a 3-year 3-month-old female with features of CACP syndrome.