What is mixed connective tissue disease?

Mixed connective tissue disease (MCTD) is a disorder characterized by a mixture of other well-defined connective tissue disorders such as systemic lupus erythematosus, progressive systemic sclerosis, dermatomyositis, and even Sjögren’s syndrome. Most patients with MCTD have anti-U1RNP ribonuclear protein (U1RNP) antibodies. Patients often present with Raynaud’s phenomenon, swelling of the digits (dactylitis), and arthritis. Patients may develop myositis, sclerodermoid lesions of the skin, and, later, sclerodactyly. Interstitial lung disease and renal disease may ensue.

Venables PJ: Mixed connective tissue disease, Lupus 15:132–137, 2006.