CAPS (Cryopyrin-Associated Periodic Syndrome): An Overview

CAPS (cryopyrin-associated periodic syndrome) is a group of rare genetic diseases that can cause rashes, fevers, joint pain, and other inflammatory symptoms. These symptoms often occur after exposure to cold or damp air or a drop in temperature, but symptoms may also show up for no clear reason. Cryopyrin is a protein responsible for triggering the inflammation and painful symptoms of CAPS (cryopyrin-associated periodic syndrome). A malfunction in this protein is what these diseases have in common.

These diseases are described below:

FCAS
Familial Cold Autoinflammatory Syndrome is the most common and least severe type.

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

MWS
Muckle-Wells Syndrome is more severe than FCAS.

  • Symptoms: Those symptoms listed above, as well as loss of hearing. High protein levels are detected during screening and are a sign of the disease
  • Onset of symptoms: At birth or, rarely, later in childhood
  • Trigger of symptoms: Exposure to cold temperature, weakness of the body, or other reasons that are not yet known
  • Duration of symptoms: Usually last between 1 and 3 days

NOMID
Neonatal-Onset Multisystem Inflammatory Disease is the most severe type.

  • Symptoms: All of the above mentioned symptoms, as well as loss of eyesight, swelling of the knees, and mental disability
  • 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

People typically have 1 of the 3 forms. Those who are more severely affected may develop permanent damage to major organs and joints throughout the body. But even in its mildest form, the symptoms of CAPS (cryopyrin-associated periodic syndrome) can be chronic and often painful.

In the United States, there are approximately 300 cases, but many patients may remain undiagnosed due to poor disease recognition.

CAPS (cryopyrin-associated periodic syndrome) develops because of a genetic change that may be passed down from a common ancestor through the generations, or it may show up spontaneously in families with no history of the disease. Family members who have CAPS (cryopyrin-associated periodic syndrome) may share a cluster of symptoms such as rashes, fever, joint pain, eye swelling or redness, and hearing loss.

Outbreaks often occur after a person is exposed to cold temperature, but symptoms can also occur without an obvious reason. Some people may not know that they have CAPS (cryopyrin-associated periodic syndrome), but they certainly know something is wrong due to the clusters of uncomfortable symptoms. Undiagnosed chronic (lifelong) disease can be very discouraging. Because CAPS is so rare, doctors do not think of this syndrome first, which may delay diagnosis. People who think they or someone close to them may have CAPS (cryopyrin-associated periodic syndrome) should see a doctor and voice their concerns.

Only a doctor can determine whether a person has CAPS (cryopyrin-associated periodic syndrome), so patients should discuss all symptoms with their doctors. In addition to other tests, there is a genetic screening that can help doctors to diagnose CAPS.