Mixed connective tissue disease (MCTD)
Mixed Connective Tissue Disease (MCTD) is an autoimmune disorder characterized by features commonly seen in three other connective tissue diseases: systemic lupus erythematosus, scleroderma, and polymyositis. MCTD is thus considered an overlap syndrome. Patients with MCTD may exhibit a variety of symptoms, including joint pain, muscle weakness, Raynaud's phenomenon (a condition where fingers and toes turn white or blue and feel cold in response to cold temperatures or stress), and problems with internal organs such as the lungs and kidneys. A distinctive marker for MCTD is the presence of high levels of anti-U1 ribonucleoprotein (anti-U1 RNP) antibodies in the blood. The course of MCTD varies among individuals; some experience only mild symptoms, while others may have a more severe progression requiring active management. Treatment is tailored to the individual's symptoms and may include medications that suppress the immune system, such as corticosteroids and immunosuppressants.