Juvenile Myelomonocytic Leukemia (JMML)

What is juvenile myelomonocytic leukemia?

Juvenile myelomonocytic leukemia (JMML) is a rare, severe form of childhood blood cancer. It occurs when there is an excess of myelocytes and monocytes that never fully mature into white blood cells. They crowd out healthy blood cells and cause the characteristic symptoms.

What are the symptoms of juvenile myelomonocytic leukemia?

Common symptoms of this cancer are:

Infections
Fever
Easy bruising and bleeding
Fatigue
Poor appetite
Failure to thrive
Red rash or tiny red dots on the skin
Irritability
Painless swelling of the lymph nodes
Pain below the ribs
Unexplained weight loss
Dry cough
Anemia
Enlarged liver and/or spleen

What causes juvenile myelomonocytic leukemia?

The exact cause of this cancer is unknown. They do know that issues with tumor suppressor genes contribute, and about 25% of cases are due to a mutation in the RAS family of genes. 15-20% are caused by a mutated NF1 gene. 35% are the result of a mutation in the PTPN11 gene, and 10% the CBL gene. The remaining cases do not have an identifiable cause. There are also genetic disorders that increase one’s chance of cancer, such as Noonan syndrome.

How is juvenile myelomonocytic leukemia diagnosed?

Doctors will first look at a patient’s medical history and perform a physical exam. They will also use blood tests, genetic mutation testing, biopsies, and bone marrow aspirations.