Mixed Connective Tissue Disease - MCTD

Mixed Connective Tissue Disease - MCTD

 

Mixed connective tissue disease (MCTD) is an autoimmune connective tissue disease.

  • Exhibits varied combinations of features common to other autoimmune diseases such as:
    • Systemic lupus erythematosus
    • Polymyositis
    • Rheumatoid arthritis
    • Systemic sclerosis

Epidemiology

  • Incidence – uncommon autoimmune disorder
  • Age – mean age of onset in 2nd and 3rd decades

Clinical Presentation

  • Raynaud phenomenon
  • Musculoskeletal – arthritis, polymyositis, swollen hands  
  • Neurologic – trigeminal neuralgias, aseptic meningitis
  • Pulmonary – pleuritis, fibrosis
  • Renal – glomerulonephritis
  • Gastrointestinal – esophageal dysmotility
  • Cardiac – pericarditis

Diagnosis

  • Laboratory testing
    • Connective tissue antibody testing
      • Multiple autoantibodies may indicate MCTD or other autoimmune diseases
        • RNP antibodies found in 95-100% MCTD patients
        • RNP antibodies considered specific for syndrome if other antibodies negative
Distribution of Antibodies in Connective Tissue Disease Types
  Systemic Lupus Erythematosus (SLE) Sjögren Syndrome Mixed Connective Tissue Disease (MCTD) Progressive Systemic Sclerosis (PSS) Scleroderma
dsDNA abs 50-60% 20-30% 20-25% <5%  
Histone abs Idiopathic 18-53%
Drug-induced 80-95%		   <20% <20% <20%
RNP 20-30%   95-100% 15-25% 5-10%
Scl-70       25% 20-60%
SSA ANA positive patients
30-40%		 70-75%   5-10%  
SSB 15-25% 50-60%   5-10%  
Jo-1 abs Found in polymyositis, dermatomyositis, myositis associated with rheumatic disease

See Also