Mixed Connective Tissue Disease

Rare (incidence 2/million)

Many symptoms / lab findings  possible:
  • Raynaud’s phenomenon common
  • ANA ↑
Mimics SLE.  Distinguish by:
  • No renal or CNS involvement
  • Arthritis worse
  • SLE Antibodies negative
  • MCTD Antibody:  Anti-U1 RNP

Invariably Dx’d by rheumatology during W/U for atypical SLE

See posting Polyarthralgias.

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