National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Camptodactyly arthropathy coxa vara pericarditis syndrome


Other Names:
Arthropathy camptodactyly syndrome; Pericarditis arthropathy camptodactyly syndrome; PAC syndrome; Arthropathy camptodactyly syndrome; Pericarditis arthropathy camptodactyly syndrome; PAC syndrome; Fibrosing serositis, familial; Camptodactyly arthropathy pericarditis syndrome; Congenital familial hypertrophic synovitis; Camptodactyly-arthropathy-coxa vara-pericarditis syndrome; Arthropathy-camptodactyly syndrome; CACP syndrome; Camptodactyly-arthropathy-coxa-vara-pericarditis syndrome; Jacobs syndrome; Pericarditis-arthropathy-camptodactyly syndrome See More
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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.
Last updated: 10/9/2016

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.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Arthritis
Joint inflammation
0001369
Arthropathy
Disease of the joints
0003040
Autosomal recessive inheritance 0000007
Congenital finger flexion contractures 0005879
Constrictive pericarditis 0002563
Coxa vara 0002812
Flattened metacarpal heads
Flattened head of long bone of hand
0011909
Flattened metatarsal heads
Flattened head of long bone of foot
0005194
Generalized morning stiffness 0005197
Synovial hypertrophy 0005186
Wrist flexion contracture 0001239
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Last updated: 7/1/2020
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]
Last updated: 10/9/2016
The condition is inherited in an autosomal recessive manner.[1][3][4] This means that to be affected, a person must have a mutation in both copies of the PRG4 gene in each cell. People with CACP inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When two carriers of an autosomal recessive condition have children, each child has a:
  • 25% chance to be affected (have CACP)
  • 50% chance to be an unaffected carrier like each parent
  • 25% chance to be unaffected and not a carrier
Last updated: 10/9/2016
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]
Last updated: 10/9/2016

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]

Last updated: 10/9/2016

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

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.

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  1. Victor A. McKusick. Camptodactyly-arthropathy-coxa vara-pericarditis syndrome; CACP. Online Mendelian Inheritance in Man; http://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.