Mutations in MIS-C patients were found also in other genes related to autoimmune diseases like MCM4 and DOCK8 (both mutated in 3 MIS-C patients) and FCN3, mutated in two MIS-C patients and previously found mutated in patients with immunodeficiency and autoimmunity by our group, all bearing the Leu117fs pathogenic mutation (unpublished results). This evidence concerns the gene FCN3 and COVID-19–associated multisystem inflammatory syndrome in children.