Autoinflammatory diseases are part of a heterogeneous group of diseases that manifest themselves through an inflammatory reaction in their initial phase (innate immunity) that is activated inappropriately: either because the reaction is too strong or because it is unjustified (for example, in the absence of infection).

In many cases, and in their initial description, autoinflammatory diseases have a genetic origin (and are therefore hereditary or familial) and preferentially affect children or young adults. However, a significant number of other diseases have expanded this nosological field due to the preponderance of autoinflammation in explaining the symptoms. Sometimes, autoinflammatory disease can also remain "unclassified." In general, autoinflammatory diseases manifest as recurrent attacks combining fever, skin rashes, and joint pain. Certain signs are more specific to certain diseases, such as hives, abdominal pain, mouth ulcers, or swollen lymph nodes in the neck. It is mainly the recurrence of attacks and their unprovoked nature that attract the attention of the patient and the doctor. These attacks are systematically associated with an increase in inflammatory markers in the blood.

Currently, most autoinflammatory diseases are diagnosed based on a combination of clinical and biological evidence, following a thorough investigation by specialists in these diseases. Biological markers that can confirm the disease are rare. However, for some of them, confirmation can be obtained through genetic analysis. In certain cases, extensive genetic analysis may be offered.

Autoinflammatory diseases are managed by specialists (internists, rheumatologists, etc.) in close collaboration with primary care physicians and other healthcare professionals (nurses, physical therapists, social workers, etc.).

Treatment is sometimes based on exceptional drugs that can only be prescribed and dispensed in hospitals.

This multicenter, national study, which targets children and adults with rare autoinflammatory diseases, aims to identify:

• the "key" parameters for a faster diagnosis,
• the determining factors and their associated characteristics, and
• the treatments used and their effectiveness.

Inclusion Criteria:

- Adult patient > 18 years old Minor patient (aged 4 years and 6 months to 18 years) Patient diagnosed with a rare autoinflammatory disease Patient treated at the Hospices Civils de Lyon in the department participating in the research Patient affiliated with social security

Exclusion Criteria:

• none

Enrolment may be extended to a maximum of 50 patients with rare autoinflammatory diseases followed up in the medical departments of the centers participating in the study.

• minor patients, as 70% of rare autoinflammatory diseases are expressed and diagnosed in childhood (Familial Mediterranean Fever (FMF), Periodic Fever-Aphthous Stomatitis-Pharyngitis-Adenopathy Syndrome (PFAPA), Cryopyrin-Associated Periodic Syndrome (CAPS), Mevalonate Kinase Deficiency (MVK)).
• adult patients, as certain rare autoinflammatory diseases are discovered in adulthood (FMF depending on variant, tumor necrosis factor receptor 1-related relapsing fever syndrome (TRAPS)) or are revealed in adulthood (adult STILL disease, Behçet syndrome, Schnitzler syndrome, VEXAS syndrome (Vacuoles, Enzyme E1, X-linked, Autoinflammatory, Somatic))