Calcification of Joints and Arteries

Background:
Arterial Calcifications due to Deficiency in CD73 (ACDC) is a rare genetic disease. People with ACDC develop calcification in the arteries of the lower extremities as well as calcium deposit in the joints of the fingers, wrists, ankles and feet. The lower extremities calcification causes claudication because of severe ischemia requiring at time revascularization procedures. the calcium deposits in the joints causes severe debilitating pain in the hands and feet. Currently, there are no standard treatments for ACDC.
Etidronate is a bisphosphonate that interferes with bone metabolism. It is approved to treat Paget's disease, a condition in which the bones are soft and weak and may be deformed, painful, or easily broken. It is also used to treat high blood calcium levels. Researchers want to see if it can be used to treat the calcifications of ACDC and improve pain and blood flow in the lower extremities and arthritic pain of the hands and feet.
Objectives:
- To see if etidronate is a safe and effective treatment for ACDC.
Eligibility:
- People between 18 and 80 years of age who have been diagnosed with ACDC.
Design:
Participants will be screened with a physical exam and medical history. They will also have imaging studies, including CT scan of the lower extremities, x-rays and DEXA bone scans, before starting treatment. Blood and urine samples will be collected. An exercise tolerance test will also be given and ABI (ankle brachial index will be measured.
Participants will take etidronate by mouth once a day for 14 days every 3 months. They will be assigned an individualized 6- month drug schedule to follow.
Participants will have regular study visits throughout the treatment period. These visits will involve imaging studies, full dental exams, and blood and urine tests. Participants will also have exercise tolerance tests and ABIs measured.
Participants may also provide tissue samples for further study.
Treatment will continue for up to 3 years as long as the side effects are not severe and the condition does not become worse. Participants will have a final follow-up visit after stopping treatment.

Researchers intend on diagnosing and treating certain inborn errors of metabolism. By doing this researchers hope to expand their knowledge about these disorders and provide access to patients of interest for research, teaching, and clinical experience.
Patients participating in this study will be examined and treated on an out patient basis, if practical. However, patients requiring specialized tests or treatments will be admitted to the NIH Clinical Center as necessary. Researchers will use only accepted medical procedures in diagnosing (medical history, physical examinations, X-ray studies, eye examinations, blood tests, and urine tests) and treating the patients involved in this study. Additional tests may be required on a case to case basis.
Many patients seen in this study will go on to be enrolled in a specific disease-related research study.