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Disease Profile

Camptodactyly arthropathy coxa vara pericarditis syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Arthropathy camptodactyly syndrome; Pericarditis arthropathy camptodactyly syndrome; PAC syndrome;


Congenital and Genetic Diseases; Musculoskeletal Diseases; Nervous System Diseases


Camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is a rare condition which causes joint abnormalities that begin at birth or during early childhood. The name comes from the main symptoms, including permanent bending of the fingers (camptodactyly), joint disease (arthropathy), and changes in the hip joint resulting in shortened legs and a possible limp (coxa vara). Some people with CACP also have too many cells between their joints (synovial hyperplasia) and too much fluid around the heart (pericardial effusion) or lungs (pleural effusion).[1] 

Camptodactyly-arthyropathy-coxa vara-pericarditis syndrome is caused by a mutation in the PRG4 gene. This gene is responsible for making a protein that lubricates the joints.The condition is inherited in an autosomal recessive manner. CACP may be at first confused with juvenile idiopathic arthritis because the two diseases have similar symptoms.[2] 

Diagnosis is based on clinical findings (symptoms which the doctor notices on a physical exma) and a biopsy of the fluid between the joints (synovial fluid).[2] Genetic testing can confirm the diagnosis.[3] Treatment options such as physical therapy and pain medication focus on relieving symptoms of the disease. The medication for juvenile idiopathic arthritis is not helpful for those with CACP.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Joint inflammation
Disease of the joints
Autosomal recessive inheritance
Congenital finger flexion contractures
Constrictive pericarditis
Coxa vara
Flattened metacarpal heads
Flattened head of long bone of hand
Flattened metatarsal heads
Flattened head of long bone of foot
Generalized morning stiffness
Synovial hypertrophy
Wrist flexion contracture


Camptodactyly-arthropathy-coxa-pericarditis syndrome is caused by a change (mutation) in the PRG4 gene.[1][2][3][4] This gene provides the instructions for making lubricin, a protein (part of synovial fluid) that lubricates the joints.[1][4] In other words, lubricin works like oil in a hinge and is needed so the joints can bend easily without a lot of force or causing damage to the bones. Lubricin also works as an lubricant between the two layers of the thin sac which surrounds the heart (pericardium).[4] The pericardium holds the heart in place and helps it work properly.[3][5] In addition lubricin keeps the thin coverings of tendons (tendon sheaths) from sticking to the thin fibrous coverings (sheaths) of muscles and organs as well as controls cell growth of special cells (synovial fibroblasts) which are part of the thin covering (synovial membrane) surrounding the synovial fluid within joints.[1][3][4]


Diagnosis of CACP is based on clinical findings (symptoms which the doctor notices during a physical exam), X-rays of the joints, cardiac ultrasound (also called an echocardiogram), and a biopsy of the fluid between the joints (synovial fluid). Genetic testing can confirm the diagnosis. CACP may at first be confused with juvenile idiopathic arthritis (JIA) because the two diseases may have similar symptoms.[2][3][6]

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


At present there is no cure or specific treatment for camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP). Treatment options such as physical therapy and pain medication focus on relieving the symptoms of the disease. Hip joint replacement surgery may also be an option.[7] The medication for juvenile idiopathic arthritis is not helpful for those with CACP.[2][6]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Camptodactyly arthropathy coxa vara pericarditis syndrome. Click on the link to view a sample search on this topic.


  1. Victor A. McKusick. Camptodactyly-arthropathy-coxa vara-pericarditis syndrome; CACP. Online Mendelian Inheritance in Man; https://www.omim.org/entry/208250.
  2. Ritu Manoj Kakkar, Sameer Soneji, Rashmi R. Badhe,and Shrinivas B. Desai. Camptodactyly-Arthropathy-Coxa Vara-Pericarditis Syndrome: Important Differential for Juvenile Idiopathic Arthritis. Journal of Clinical Imaging Science. June 29, 2013; 3:24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3779395/.
  3. Ciullini Mannurita S, Vignoli M, Bianchi L, Kondi A, Gerloni V, Breda L, Ten Cate R, Alessio M, Ravelli A, Falcini F, and Gambineri E. CACP syndrome: identification of five novel mutations and of the first case of UPD in the largest European cohort. European Journal of Human Genetics. February 2014; 22(2):197-201. https://www.ncbi.nlm.nih.gov/pubmed/23756439.
  4. Ai M, Cui Y, Sy M, Lee D, Zhang L, Larson K, Kurek K, Jay G,and Warman M. Anti-Lubricin Monoclonal Antibodies Created Using Lubricin-Knockout Mice Immunodetect Lubricin in Several Species and in Patients with Healthy and Diseased Joints. PLoS One. February 2, 2015; 10(2):e0116237. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4314068/.
  5. Pericardial Disorders. MedlinePlus; https://medlineplus.gov/pericardialdisorders.html. Accessed 10/9/2016.
  6. Madhusudan S, Gupta A, Prakash M, Matta D, Suri D, and Singh S. Camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome: a mimicker of juvenile idiopathic arthritis. Scandinavian Journal of Rheumatology. October 2015; 28:1-2. https://www.ncbi.nlm.nih.gov/pubmed/26508154.
  7. Murphy JM, Vanderhave KL, Urquhart AG. Total hip arthroplasty in adolescents with severe hip arthropathy and dysplasia associated with camptodactyly-arthropathy-coxa vara-pericarditis syndrome. The Journal of Arthroplasty. September 2012; 27(8):1581.e5-8. https://www.ncbi.nlm.nih.gov/pubmed/22386609.

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