The camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is an autosomal recessive disorder caused by mutations in the Proteoglycan 4 (PRG4), a chondroitin sulfate proteoglycan that acts as a lubricant for the cartilage surface. Affected individuals present with arthropathy associated with camptodactyly. Some patients have pericarditis with effusions.
