Overlap syndrome

Overlap syndrome
Specialty	Rheumatology

An overlap syndrome is a medical condition which shares features of at least two more widely recognised disorders. Examples of overlap syndromes can be found in many medical specialties such as overlapping connective tissue disorders in rheumatology, and overlapping genetic disorders in cardiology.

Rheumatology

Examples of overlap syndromes in rheumatology include

In overlap syndrome, features of the following diseases are found (most common listed):^[1]

• Systemic lupus erythematosus
  (SLE)
• Systemic sclerosis
• Polymyositis
• Dermatomyositis
• Rheumatoid arthritis (RA)
• Sjögren's syndrome
• Eosinophilic granulomatosis with polyangiitis (EGPA)
• Autoimmune thyroiditis
• Antiphospholipid antibody syndrome

The treatment of overlapping connective tissue disorders is mainly based on the use of

In cardiology, genetic conditions such as Brugada syndrome can share features with related disorders caused by mutations in the same gene. An overlap syndrome can be seen whereby a mutation in the SCN5A gene encoding the cardiac sodium channel causes a reduction in the peak sodium current leading to the typical ECG features of Brugada syndrome, but which simultaneously increases the sustained late sodium current leading to the ECG features of Long QT syndrome type 3.^[5] Brugada syndrome can also overlap with arrhythmogenic cardiomyopathy due to certain mutations in the plakophilin gene.^[6]

Pulmonology

In pulmonology,

• Autoimmune
• Mixed connective tissue disease

References