Juvenile Myelomonocytic Leukemia Facts
About one to two percent of children with leukemia have juvenile myelomonocytic leukemia (JMML). This means only 25 to 50 new cases a year in the United States. JMML mainly affects children younger than four years old, with the average age being two years old. In this disease, myelocytic and monocytic blood cells grow excessively.
Symptoms
Symptoms for JMML are typical of any child with many illnesses, but if these symptoms don’t go away on their own quickly, it’s best to see your doctor. Typical JMML symptoms are:
- Paler skin than usual
- Fever
- Infection
- Bleeding of the skin, mouth and nose
Children with JMML have a cough and fail to gain weight. Many develop a red skin rash and enlarged lymph nodes. Some have small yellowish skin tumors and brown spots (called cafe-au-lait spots), which are characteristic of neurofibromatosis. Other symptoms that your doctor will look for include enlarged liver or spleen, and abnormal blood cell counts, like high white blood cells (leukocytosis), low red blood cells (anemia) and low platelets (thrombocytopenia), in addition to an increased concentration of myelocytes and monocytes.
Diagnosis
Because the symptoms for JMML are so similar to several other illnesses, your doctor doctor will perform a physical exam as well as a complete blood cell count. Other tests make be required.
Risk Factors
There are two conditions that are seemingly related to JMML. Neurofibromatosis type 1 (NF1) is diagnosed in approximately one in 10 patients with JMML. Children with NF1 are at considerable risk for developing JMML.
Infants with Noonan syndrome are possibly at risk for developing JMML or a similar disorder. Noonan syndrome is characterized by distinct facial features, growth retardation and heart anomalies. Children with Noonan syndrome who do develop a JMML-like disorder often get better without aggressive treatment by the time the child turns one year old.