Mixed Connective Tissue Disease

A diagnosis can be difficult to make because the three conditions (SLE, scleroderma and polymyositis) that can be seen in MCTD usually occur one after the other over a long period of time, rather than at the same time. It may take several years to make an accurate diagnosis of MCTD.

There are four features that point to MCTD rather than another connective tissue disorder:

• High concentrations in blood tests of a particular antibody called anti-U1-RNP (ribonucleoprotein).
• An absence of severe kidney and central nervous system problems often found in SLE patients.
• Severe arthritis and pulmonary hypertension, which may not be found in people with either SLE or scleroderma.
• Raynaud phenomenon, and swollen hands or puffy fingers, which occur in only about 25% of people with SLE.