Cryopyrine-associated periodic syndrome (CAPS) refers to a group of three autoinflammatory diseases that share a common genetic basis. These include familial cold-induced autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and chronic infantile neuro-cutaneo-articular syndrome (CINCA syndrome).
The causes are mutations in the NLRP3 gene, which codes for the protein cryopyrin. The consequence of the mutation is increased interleukin-1β production, which leads to systemic inflammatory reactions. First symptoms usually appear shortly after birth or in childhood, the symptoms may be chronic or occur after certain triggers.
Frequently, any contact with cold (cold food, air conditioners, cool breeze, swimming), stress, or physical activity causes symptoms. It is characterized by hives-like redness all over the body, which usually causes no itching and after a delay.
The symptoms last at least 12-24h. FCAS is the mildest form, with redness and headaches and conjunctivitis.
From adulthood, the hearing increasingly deteriorates. In MWS, outbreaks occur almost daily, with patients suffering from conjunctivitis and arthralgia and swelling of the joints. CINCA is the most severe form. Symptoms already exist from birth and are usually chronic.
It can lead to serious complications such as chronic aseptic meningitis, high brain pressure, congestion papilla with blindness and systemic amyloidosis with damage to liver and kidney.
The children are usually mentally retarded and suffer from malformations on the face. Due to the joint swelling, the mobility is often severely limited. CAPS is inherited autosomal dominant, but mutations can also occur spontaneously at conception.
The prognosis depends on the subtype, those with CINCA usually die before adulthood. For milder forms and early medication, the prognosis is better.