Clinical Research Directory

Inclusion Criteria: * Patients aged between 9 and 25 years; * Written informed consent to participate in the study obtained prior to the start of the study from the patient or both parents/legal guardians of the patient if a minor, and the assent of the minor; * Diagnosis of JFS according to the 2010 American College of Rheumatology (ACR) criteria 15, with disease onset before 18 years of age; * Willingness to comply with follow-up visits and provide biological samples (blood and stool) according to the schedule defined in the protocol. Exclusion Criteria: * any conditions that may affect the ability to complete informed consent; * denial of the informed consent; * presence of concomitant organic GI diseases, such as inflammatory bowel disease, celiac disease, eosinophilic or autoimmune gastroenteropathies, or history of major abdominal surgery; * acute infection at the time of recruitment; * antibiotic treatment within 3 months prior to recruitment; * use of any prebiotic, probiotic, or postbiotic in the previous 2 months before enrolment; * significant eating disorders, including diagnosed eating behaviour disorders.