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Juvenile myelomonocytic leukemia (JMML) is a rare type of blood cancer that occurs when bone marrow production of white blood cells becomes severely dysregulated. In children with JMML, bone marrow — the soft, spongy center of the bones responsible for
creating blood cells — produces immature white blood cells that grow too rapidly and keep reproducing even when they run out of space. This crowds out healthy bone marrow cells and can lead to symptoms such as infections, anemia, and bleeding. Currently,
the only cure for JMML is stem cell transplant.
Children and teens with JMML are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center through the Childhood Leukemia Program, one of the top programs worldwide for pediatric leukemia. Our program has been instrumental in refining
treatments for childhood leukemia, which has resulted in improved cure rates and decreased side effects. We also have one of the largest and most experienced pediatric stem cell transplant programs in the U.S.
Dana-Farber/Boston Children's offers a wide array of support services and programs for pediatric patients and their families during and after cancer treatment.
Because JMML is a cancer of the blood-forming bone marrow, initial symptoms are often related to abnormal bone marrow function. The bone marrow is responsible for storing and producing about 95 percent of the body's blood cells, including the red blood
cells, white blood cells, and platelets. While each child may experience symptoms of JMML differently, some of the most common symptoms include:
Symptoms of JMML may resemble other blood disorders or medical problems. Because many of these symptoms can also point to other conditions, it's important to have your child evaluated by a qualified medical professional right away for an accurate diagnosis
and prompt treatment.
About 90% of children diagnosed with JMML have been found to have specific genetic mutations. These mutations occur in a type of white blood cell known as a monocyte, which are a part of the body's immune system. Children with Neuroﬁbromatosis type 1
and Noonan syndrome are more likely to develop JMML.
It's important to understand that there's nothing you could have done or avoided doing that would have prevented your child's cancer from developing.
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