Familial Cold Autoinflammatory Syndrome (FCAS)

What is familial cold autoinflammatory syndrome (FCAS)?

Familial cold autoinflammatory syndrome (FCAS) is an extremely rare condition that causes intense episodes of fever, rashes, and joint pain after the individual has been exposed to cold temperatures. Episodes usually begin in infancy and continue throughout one’s life. For many, the episodes will occur after an hour of cold exposure, but some only have to be exposed for a few minutes for an episode to happen.

What are the symptoms of FCAS?

The symptoms of this syndrome are triggered by exposure to cold temperatures, anytime between 10 minutes and 8 hours after the exposure. They include:

• Itchy, burning rash that usually starts on the face or extremities and spreads
• Fever (may last from a few hours to three days)
• Joint pain
• Conjunctivitis (redness in the whites of the eyes)
• Swelling
• Fatigue
• Muscle pain
• Intense sweating
• Headache
• Nausea
• Extreme thirst
• Blurred vision, watering eyes

Episodes usually last for less than day.

What causes FCAS?

Human traits are inherited from a person’s father and mother; each one contributes a copy of a gene, which interacts with the other copy. When a gene mutates, it can lead to disease. This condition is caused by mutations in either the NLRP3 or NLRP12 genes. These genes normally give instructions for making proteins that help regulate the process of inflammation in the immune system. When these genes change, the body’s ability to control inflammation is impaired, which causes symptoms. However, it is still unclear why the episodes are triggered by exposure to cold. FCAS is inherited in an autosomal dominant pattern, which means that only one parent needs to pass down a copy of the gene for the condition to occur. Rarely, the condition may occur in people with no family history of it, meaning that the mutation happened spontaneously.

How is FCAS diagnosed?

FCAS is diagnosed using the following procedures:

• Recording of characteristic findings
• Recording of family history
• Genetic testing

What are the treatments for FCAS?

FCAS treatment includes:

• Avoiding exposure to cold temperatures
• Medication
• Bed rest
• Warmth
• Corticosteroids

Where can I find out more about FCAS?

• National Organization for Rare Disorders (NORD)
• Autoinflammatory Alliance
• NIH