About CAPS About CAPS

What are CAPS?

Cryopyrin-Associated Periodic Syndromes (CAPS) are a group of rare and genetic diseases that include Familial Cold Autoinflammatory Syndrome (FCAS) and Muckle-Wells Syndrome (MWS). CAPS are chronic diseases that belong to a larger group of diseases known as Periodic Fever Syndromes.

Children can develop CAPS at any point throughout childhood, but FCAS symptoms typically appear during infancy or early childhood, while MWS tends to appear during early adolescence.

It is estimated that only about 1 in 1 million people in the United States have CAPS. But because the symptoms of CAPS can appear similar to those of other conditions, some experts believe that there are people living with CAPS who have either been overlooked or misdiagnosed.

What causes CAPS?

CAPS are genetic diseases that are generally passed on from other family members. CAPS are caused by an inherited mutated gene, called the NLRP3 gene (or the CIAS1 gene). In some cases, however, the genetic mutation responsible for CAPS may occur spontaneously at birth.

A mutated NLRP3 gene causes overactivation of a protein called cryopyrin, which then causes the uncontrolled production of interleukin-1 beta (IL-1β). IL-1β is a protein that is part of the body's immune system. Too much IL-1β in the body can lead to inflammation and other symptoms of CAPS.

Talking to your family members about CAPS

Because CAPS are a genetic condition, you may want to talk about CAPS with your family. The Your Family and CAPS Brochure can provide information to help you start the conversation.

FCAS and MWS: What's the Difference?

Muckle-Wells Syndrome (MWS) is considered to be more severe than Familial Cold Autoinflammatory Syndrome (FCAS). MWS symptoms are thought to be more frequent, more severe, and longer lasting than FCAS symptoms.

If you have questions about CAPS and about how ILARIS® can help, ask your doctor or call 866-972-8315.

Next: Signs and Symptoms