Platelets of 1000 x 10^9/L in infants may be the result of diseases such as primary myelofibrosis. Primary myelofibrosis is a proliferative tumor of the bone marrow that occurs most often in the middle-aged and older population, about 50 to 70 years old, but it can also be seen in children and even infants. And the platelet count of the patients varies in height, about 1/3 of the patients will have increased platelets, and there are a few patients who may have 1000×10^9/L. Therefore, primary myelofibrosis is mostly considered in infants with platelets of 1000×10^9/L. However, the disease starts slowly, some patients have no conscious symptoms at the time of diagnosis, and some patients may only experience weakness, excessive sweating, emaciation, etc. With the development of the disease, patients may also experience anemia, fever, bone pain, etc. A small number of patients may also induce kidney stones and hearing loss. Parents are advised to consult a doctor for timely examination and systematic treatment as prescribed by the doctor when they find that the platelet count of their infants is 1,000 x 10^9/L.