The Centers for Disease Control and Prevention (CDC) case definition of MIS-C developed a new case definition for MIS-C diagnostic criteria, including: persistent fever > 38° C, without an alternative diagnosis and the exclusion of other microbiological etiologies, in a patient with a serious clinical picture; C-reactive protein (CRP) > 3 mg/dl; > 2 new-onset manifestations of the following: conjunctivitis, oral mucosal changes, rash, erythema and/or oedema of the extremities; abdominal pain, vomiting, diarrhoea; lymphocyte count < 1000/μl, platelet count < 150,000/μl. This evidence concerns the gene CRP and conjunctivitis.