Question: I have an autoimmune disease called “mixed connective tissue disease.” My doctor does not know much about this disease. Could you help me understand what I have to look forward to? I am only 28 years old.

Dr. Hibberd's Answer:

MCTD (mixed connective tissue disease) is a label attached to an uncommon subset of autoimmune diseases that have variable features of several autoimmune diseases including systemic lupus (SLE), scleroderma, polymyositis, dermatomyositis, and rheumatoid arthritis, but do not fulfill the diagnostic criteria for any of them.

Its peak incidence is in the teens and 20s, and its cause is unknown. It sometimes evolves into SLE or scleroderma. The 10 year survival rate is 80%, but this is dependant upon the organ systems involved. The general management is similar to SLE. It seems that each case has unique features which determine its eventual course.

The course of the disease is highly variable, and usually not easy to predict. The large majority of patients are not disabled by this condition while under treatment, and some go into extended periods of remission for many years without treatment.

The likely reason your doctor seems to know so little is it can present in so many different, varying, and unpredictable ways, and there is no uniform prognosis. Its diagnosis is established by clinical features, antibodies to RNP (speckled antinuclear antibody to ribonucleoprotein antigen), hand swelling, joint aches, Raynaud’s phenomenon, and the absence of antibodies specific for other autoimmune diseases. Almost all patients have aching joints, and 75% have arthritis that is often not deforming, with or without muscle weakness. About 10% develop renal disease and sensory neuropathy, especially of the trigeminal nerve which causes facial pain.

Mild disease usually responds to NSAIDs and anti-malarial drugs, while more aggressive disease that involves major organs may need immune suppressants and corticosteroid treatment.

The prognosis for this disease is so variable that it’s hard to make any prediction of future effects. MCTD may be a recognized autoimmune disease that hasn’t fully developed, and it may, or may not, evolve into one of the more defined autoimmune syndromes later on. It certainly seems to lack the aggressive deformities and organ dysfunction so often seen with the other well-defined autoimmune disorders.