Juvenile Myelomonocytic Leukemia (JMML)

What is Juvenile Myelomonocytic Leukemia?

Juvenile myelomonocytic leukemia (JMML) is a rare childhood cancer that usually happens in children younger than 2 years old. In JMML, too many myelocytes and monocytes (two types of WBCs) are produced from immature blood stem cells called blasts. These myelocytes, monocytes, and blasts overwhelm the normal cells in the bone marrow and other organs.

What causes Juvenile Myelomonocytic Leukemia? Who is affected?

The causes for juvenile myelomonocytic leukemia are unknown, but doctors do know that certain medical conditions such as neurofibromatosis type I (NF1) and Noonan syndrome can make a child more likely to develop it. Children are primarily affected by JMML, most often diagnosed in children younger than 2 years.

What are the symptoms of Juvenile Myelomonocytic Leukemia?

Symptoms for juvenile myelomonocytic leukemia may not always be present at first but will start to develop later. Symptoms can include:

• Easy bruising
• Bone and joint pain
• Abdominal pain (caused by abnormal blood cells building up in organs like the kidneys, liver, and spleen)
• Swelling of the spleen and abdomen
• Fever
• Fatigue
• Swollen lymph nodes
• Recurrent infections such as bronchitis and tonsillitis

How is Juvenile Myelomonocytic Leukemia treated?

There are many treatments used for juvenile myelomonocytic leukemia, the most common and effective one is bone marrow transplant. Chemotherapy is also used but not often.