Progressive Pseudorheumatoid Dysplasia
Also refered as Autosomal Recessive SED tarda and
Progressive Pseudorheumatoid Arthropathy of Childhood
Progressive pseudorheumatoid dysplasia (PPD) is an autosomal recessive disorder that affects joints. Typically, there are no symptoms in the newborn period. Finger joint involvement is among the earliest signs, beginning between the ages of 3 and 6 years and resembling rheumatoid arthritis. PPD can be distinguished from rheumatoid arthritis based on radiographic analysis and the absence of inflammatory joint disease. As time passes, joint stiffness, contractures (being unable to move them), and pain spread to other joints. This condition appears to be caused by an underlying cartilage abnormality that results in continued cartilage loss in the joints, leading to destructive bone changes over time. Many affected individuals benefit from joint replacement therapy by early adulthood.
Our group identified the gene responsible for causing PPD. It maps to human chromosome 6 in the region 6q21. The responsible gene is called WISP3, and encodes a secreted growth regulator. Disease causing changes to this gene have been identified in many, but not all, affected individuals. We are now performing mutation detection on a research basis. To the best of our knowledge at this time, molecular testing to make the diagnosis or to identify unaffected carriers is not clinically available. Physicians seeking assistance in making this diagnosis in a patient are welcome to contact us. Additional resources that may be of value are listed below.
We are currently seeking additional individuals and families with PPD to participate in our research. We would like to identify additional disease causing genetic changes and to study their direct consequences on cartilage. We are therefore seeking blood samples for DNA analysis. Additionally, for patients undergoing a diagnostic arthroscopy or joint replacement surgery, we would be very interested in obtaining cartilage tissue. Studying the consequences of PPD at the cellular, biophysical and protein level may facilitate the development of novel therapeutic strategies.
If you are a patient, or have a patient with progressive pseudorheumatoid dysplasia interested in participating in our research, please contact us. For sample submission instructions, click on How to submit samples. Please be sure to complete the PPD data collection form and have the participant sign our consent form.
If you are a patient or family member interested in communicating with other families, please email Dr. Warman. Whenever new consenting family members contact us, emails (or phone numbers) will be exchanged. The Center for the Study of Genetic Bone and Joint Disorders does not monitor communications directly between families, and therefore cannot be responsible for the accuracy of information exchanged.
Additional information can be obtained through Online Mendelian Inheritance in Man, a database catalogue of human genes and genetic disorders edited by Victor A. McKusick and colleagues. The OMIM number for PPD is 208230.
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