Chondrocalcinosis 2

The signs and symptoms of chondrocalcinosis 2 vary from person to person. Some affected people may not have any symptoms of the condition aside from the appearance of calcium deposits on joint x-rays. Others experience chronic pain in affected joints and/or the back if calcium deposits develop around the bones of the spine.^[4][3]

Chondrocalcinosis 2 can also be associated with sudden, recurrent episodes of joint pain, stiffness and/or swelling that can last anywhere from several hours to several weeks. These episodes can lead to limited range of motion in the affected joint or even ankylosis (fixation of joint in place). Although almost any joint in the body can be affected, symptoms are often confined to a single knee, wrist, hip or shoulder.^[1][3][2][4]

Chondrocalcinosis 2 is caused by changes (mutations) in the ANKH gene. This gene encodes a protein that helps transport pyrophosphate (a substance that regulates bone formation). Mutations in ANKH can cause high levels of pyrophosphate and calcium pyrophosphate dihydrate crystals to accumulate in the cartilage of joints. The buildup of these crystals weakens cartilage and causes it to break down more easily. This leads to the many signs and symptoms associated with chondrocalcinosis 2.^[5]

Chondrocalcinosis 2 is inherited in an autosomal dominant manner.^[3] This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with chondrocalcinosis 2 has a 50% chance with each pregnancy of passing along the altered gene to his or her child.

A diagnosis of chondrocalcinosis 2 is often suspected based on characteristic signs and symptoms. Specialized testing, such as synovial fluid analysis, can then be ordered to confirm the diagnosis. In synovial fluid analysis, a small sample of the fluid that surrounds affected joints is removed and examined to determine if calcium pyrophosphate dihydrate crystals are present. In most cases, x-rays can be used to identify calcium deposits in the cartilage of joints.^[1][3][2]

There is currently no cure for chondrocalcinosis 2. Unfortunately, the accumulation of calcium pyrophosphate dihydrate crystals can not be prevented and once present, these crystals can not be removed from affected joints.^[1][2]

Therapies are available to manage the signs and symptoms of the condition. During episodes of joint pain, stiffness, and/or swelling, the following treatments may be recommended to relieve symptoms: joint aspiration (draining of fluid from the affected joint), corticosteroids injections, and/or nonsteroidal anti-inflammatory drugs (NSAIDS) such as aspirin or ibuprofen. Small doses of a medication called colchicine or NSAIDS are sometimes prescribed to people with frequent and severe attacks in an attempt to prevent future episodes; however, this therapy is not effective in all cases.^[1][2]

The long-term outlook (prognosis) for people with chondrocalcinosis 2 varies and largely depends on the severity of the condition. There is, unfortunately, no way to prevent the accumulation of calcium pyrophosphate dihydrate crystals in the joints and they can not be removed once present. In general, chondrocalcinosis 2 is not as severe as classic gout; however, some cases can be just as disabling and/or painful.^[1][3]