GATA1 and transient myeloproliferative syndrome: At present, TAM is diagnosed on the basis of a proportion of peripheral blood original cells >10% and GATA1 gene variation; however, invisible TAM is diagnosed on the basis of a proportion of peripheral blood original cells < 10% and GATA1 gene variation.[7] The proportion of peripheral blood primitive cells was >10% before and after admission, and FISH of the patient’s peripheral blood was positive for chromosome 21.