FLNC and thrombocytosis disease: • Blood tests: complete blood count in the acute stage often finds mild to moderate normochromic anemia, and in the subacute stage, it is common to find thrombocytosis, CRP, ESR, renal and liver function, albumin level, blood culture, Antistreptolysin O Titer (ASOT), urinalysis (sterile pyuria can also be present due to urethral inflammation), and culture, COVID-19 swab.• Echocardiogram: at presentations, 2 and 6 weeks after the initial tests.• Electrocardiogram.• Urine meprin A or filamin C (as a marker of Kawasaki disease activity).