OCCURRENCE OF MYELOPROLIFERATIVE DISORDER IN PATIENTS WITH NOONAN-SYNDROME

We report four cases of Noonan syndrome associated with chronic myelom onocytic leukemia in childhood, These children shared some hematologic features: thrombocytopenia, splenomegaly in the first months of life, occurrence of chronic myelomonocytic leukemia without abnormalities o f the initial bone marrow karyotype, and, in three cases, improvement of the hematologic disease, A common pathophysiologic process in such patients is suggested.