Juvenile myelomonocytic leukaemia (JMML)

JMML accounts for less than 1% of all childhood leukaemias diagnosed in the United States.

JMML is a disease of childhood, more commonly diagnosed in children under the age of four, although the average age of diagnosis is two-years-old.

Children who have been diagnosed with neurofibromatosis 1, or Noonan syndrome are at an increased risk of developing JMML.

The cause of JMML remains largely unknown. There are no proven environmental causes that contribute to the development of JMML.

The symptoms of JMML result from the malfunctioning bone marrow and may include:

Abnormal red cell function or a lack of red cells (anaemia), which causes:

• persistent tiredness and fatigue
• weakness
• shortness of breath with minimal exercise
• looking pale.

Abnormal white cell function, often with low white cell counts, which causes:

• recurring infections, especially chest infections
• fevers
• sore mouth due to mouth ulcers.

Abnormal platelet function, often with low platelet counts, which causes:

• easy bruising
• purpura – a rash of small red dots seen often on the lower limbs initially, due to small superficial capillary bleeds which are known as petechiae
• tendency to bleeding from the nose and gums.

Children diagnosed with JMML can also present with enlarged lymph nodes, liver and spleen. Other symptoms and signs include developmental delay, decreased appetite and poor weight gain. Some of these symptoms may also be seen in other illnesses, including viral infections. It is important to see your doctor if your child has any symptoms that do not go away so that they can be examined and treated properly.