What Causes CAPS (Cryopyrin-Associated Periodic Syndrome)

CAPS Is an Inherited Disease That Results in Uncontrolled Inflammation in Your Body

If you suffer from CAPS, a rare, genetic disease, you may recognize the symptoms but not quite understand what causes them. CAPS is not the result of anything you did wrong. It is a disease that you are born with.

CAPS usually occurs due to an inherited, mutated gene, called the NLRP3 gene (or the CIAS1 gene).

• When a person with the mutated gene has a child, often that gene is passed on
• The child then has a 50% chance that he or she will get CAPS

In these cases, CAPS usually can be traced back for generations. However, in a few cases, people may be born with the mutated gene without any previous history of CAPS in the family.

How the NLRP3 Gene Leads to Uncontrolled Inflammation

• The mutated gene causes overactivation of a protein called cryopyrin, which then causes the uncontrolled production of IL-1β
• IL-1β, also known as interleukin-1 beta, is a protein that is part of the body's immune system
• Buildup of IL-1β in body tissues is what causes the painful inflammation and symptoms of CAPS:
• Rash
• Fever or chills
• Headache or migraine
• Fatigue
• Muscle or joint pain
• Resulting inflammation can occur in many different parts of the body

How Inflammation in CAPS Is Different From Normal Inflammation

Under normal circumstances:

• The immune system fights off "foreign" invaders known as antigens
• Antigens may include germs, viruses, and particles like pollen or other allergens
• The immune system releases IL-1β to attack these antigens

In CAPS:

• When someone has CAPS, their immune system overproduces
  IL-1β even though there is no injury or illness
• Rather than being helpful like in the immune response, too much IL-1β production is harmful to the body

Remember Family Connections

Knowledge of the family connections in CAPS can be valuable to the health of future generations.

• A link to an ancestor with CAPS may be revealed
• Another family member presently suffering from the disease may be diagnosed

Only a physician can determine whether you or your loved one has CAPS, so be sure to discuss all symptoms with your doctor.

Download the Talking to Your Doctor Discussion Guide for a few simple suggestions to start a conversation with your doctor about CAPS.

Download the Speaking With Family About CAPS Letter, a brief letter that can be personalized and sent to other family members to let them know about CAPS and their potential risk for the disease.

If you do not suffer from CAPS but you know or care for someone who does, visit the section For Parents and Other Caregivers to learn what you can do to help.