Mixed Connective Tissue Disease (MCTD)
1. Mixed connective tissue disease (MCTD) manifests overlap features of systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and inflammatory myopathy, and is associated with high-titer speckled antinuclear antibodies (ANAs) and uridine-rich ribonucleoprotein (U1-RNP) antibodies.
2. Severe renal disease, neurologic disease, or the absence of Raynaud’s phenomenon should suggest a disease other than MCTD.
3. Pulmonary arterial hypertension (PAH) and/or interstitial lung disease (ILD) are major causes of mortality in patients with MCTD.
4. About 25% of patients presenting with features of a rheumatologic disease do not fulfill criteria for a defined disorder.
5. About 25% of patients with undifferentiated connective tissue disease (UCTD) evolve into a more specific diagnosis over time.