Kyrle and Eichinger [3] summarized the following clinical and laboratory features that should prompt clinicians to suspect CTP: inexplicable platelet fluctuations despite appropriate ITP therapy; persistent thrombocytosis while on TPO-RA treatment; a mild bleeding phenotype during severe thrombocytopenia; menstrual-synchronous fluctuations; TCR rearrangements; blood or thyroid gland disorders; fluctuations in white cell or reticulocyte counts; inverse cycling of platelet and TPO levels; and periodic megakaryocytic hypoplasia or aplasia. This evidence concerns the gene TPO and Thrombocytosis.