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The Subtypes of CAPS

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Although the genetic disease subtypes of Cryopyrin-Associated Periodic Syndromes (CAPS) share characteristics, they are each different. The subtypes of CAPS and their typical symptoms include


Familial Cold Autoinflammatory Syndrome is the most common CAPS subtype in the United States.

  • Symptoms: Rash, headache, fever or chills, feeling tired, sore or red eyes, muscle pain, or joint pain
  • Onset of symptoms: At birth or, rarely, later in childhood
  • Trigger of symptoms: Exposure to cold temperatures
  • Duration of symptoms: Episodes typically last no more than 24 hours


Muckle-Wells Syndrome is more severe than FCAS.

  • Symptoms: Those symptoms listed for FCAS, as well as loss of hearing and kidney damage
  • Onset of symptoms: Adolescence, but it can occur at any age
  • Trigger of symptoms: Exposure to cold temperatures, physical stress, or other reasons that are not yet known
  • Duration of symptoms: Episodes usually last 1 to 2 days


Neonatal-Onset Multisystem Inflammatory Disease is the most severe subtype of CAPS. Even fewer people have this disease than the 2 subtypes mentioned above.

  • Symptoms: All of the above-mentioned symptoms, as well as loss of eyesight, abnormal bone growth in the knees, and developmental problems
  • Onset of symptoms: Almost always at birth
  • Trigger of symptoms: Reasons that are not yet known
  • Duration of symptoms: Continuous, with symptoms worsening from time to time

However, the CAPS symptoms that bother one person most can change over time, and people diagnosed with one subtype of CAPS can have symptoms of the others. FCAS, MWS, and NOMID are all subtypes of CAPS.