In medicine, mixed connective tissue disease, commonly abbreviated as MCTD, is an autoimmune disease, in which the body's defense system attacks itself. It is also known as Sharp syndrome. Mixed connective tissue disease (MCTD) is a rare autoimmune disorder that causes signs and symptoms of several other connective tissue diseases. People with mixed connective tissue disease experience features of three other diseases — lupus, scleroderma and polymyositis. For this reason, mixed connective tissue disease is sometimes referred to as an overlap disease. Signs and symptoms of these three other diseases usually don't appear all at once. This makes diagnosing mixed connective tissue disease somewhat complicated. Often people with mixed connective tissue disease are first diagnosed with lupus. As the disease progresses and other signs and symptoms become apparent, the diagnosis is corrected. Mixed connective tissue disease occurs most often in women and is usually diagnosed in young adults in their 20s and 30s. However, children have occasionally been diagnosed with mixed connective tissue disease.
Mixed connective tissue disease doesn't have a unique set of signs and symptoms. Instead, people with mixed connective tissue disease usually have signs and symptoms of lupus, scleroderma and polymyositis, including: * Fatigue * Muscle weakness * Joint pain * Joint swelling * Swollen fingers * Mild fever * Raynaud's phenomenon — blood vessel spasms that interrupt blood flow to the fingers, toes, ears and nose
Doctors don't know what causes mixed connective tissue disease. The disease is part of a larger group of diseases known as autoimmune disorders. When you have an autoimmune disorder, your immune system — responsible for fighting off disease — mistakes normal, healthy cells for intruders. As a result, healthy tissue in your body is damaged, causing signs and symptoms of disease. It isn't clear what causes your immune system to attack your body. Doctors believe a complex mix of viruses, chemicals and genetic factors may be at play.
Your doctor may suspect mixed connective tissue disease based on your signs and symptoms. A physical exam may be conducted to look for signs such as swollen hands and painful, swollen joints. A blood test can determine whether you have a certain antibody in your blood that indicates mixed connective tissue disease. The presence of this specific antibody — called U1-RNP — can confirm your doctor's suspicions. Mixed connective tissue disease usually develops slowly, making it difficult to diagnose. As your signs and symptoms evolve — sometimes over many years — your diagnosis may change. Many people are first diagnosed with lupus and later re-diagnosed with mixed connective tissue disease. Others begin with a diagnosis of mixed connective tissue disease only to later find they have lupus or another connective tissue disorder.
No cure exists for mixed connective tissue disease, although treatments can help manage the signs and symptoms of the disease. Your treatment may vary from another person's because your signs and symptoms may be different. While no standard treatment exists, the most common treatment for mixed connective tissue disease is corticosteroids, such as prednisone. Other treatments may be used based on your signs and symptoms. For instance, if the signs and symptoms you're experiencing are very similar to those of lupus, your doctor may suggest trying medications typically prescribed for people with lupus. People with mild forms of mixed connective tissue disease may not need any treatment. You may require treatment only during flares or you may require constant medication. Work with your doctor to ensure that your signs and symptoms are adequately controlled.
Signs and symptoms of mixed connective tissue disease usually begin mildly and may not prompt you to seek medical attention. But if signs and symptoms become bothersome or interfere with your daily routine, make an appointment with your doctor. Also see your doctor if you've been diagnosed with lupus or another connective tissue disease and you begin developing new signs and symptoms.