Despite the fact that most children with COVID-19 have a mild course, some develop an extensive systemic inflammatory response known as MISC, which is similar to KD and can affect numerous organs, including the gastrointestinal system, skin, lymph nodes, and others; it can manifest with shock, cardiac dysfunction, acute heart failure, and extremely high levels of inflammatory biomarkers and the brain natriuretic peptide (36–38). This evidence concerns the gene NPPB and COVID-19.