Mixed Connective Tissue Disease (MCTD)

• Clinical overlap with systemic sclerosis and DM with specific serology (U1RNP) and clinical findings
• Presents with Raynaud’s phenomenon, dactylitis (‘sausage digits’), acrosclerosis, arthritis, low-grade fever; skin findings include sclerodermoid or poikilodermatous change of upper trunk; ± esophageal dysmotility, pulmonary hypertension
• Histology: may resemble LE or may show vasculitis
• Labs: hallmark is U1RNP antibody and characteristic speckled pattern on immunofluorescence
• Treatment: oral corticosteroid, steroid-sparing agent, topical steroids

Associated with HLA- DR4 and HLA-DR2