What is acute myeloid leukemia (AML)?
AML is a cancer of the blood and the bone marrow, which is the spongy tissue inside the bones. Without treatment, AML can progress rapidly and can be fatal.
How common is AML?
Approximately 20% of the childhood leukemias are of myeloid origin, which includes acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and juvenile myelomonocytic leukemia (JMML).
AML starts with changes in the DNA inside young bone marrow cells. These are called myeloid cells. Normally, a myeloid cell develops into a type of white blood cell which helps our body fight infection. However, a mutated, abnormal cell multiplies rapidly, forming a clump of cells called "leukemic myeloblasts".
Leukemic myeloblasts cannot carry out the same functions as normal blood cells. They also make it difficult for the bone marrow to produce healthy blood cells. This causes deficiencies in:
- Red blood cells. This is called anemia, which causes a child to look pale and feel tired and short of breath.
- Platelets. This is called thrombocytopenia. When a child has low numbers of platelets they bleed (for example from the nose) and bruise more easily.
- White blood cells. A specific type of white blood cell called a neutrophil is the first type of white blood cell to show up when an infection occurs. Having very low amounts of neutrophils in the blood is called neutropenia. This makes your child prone to bacterial infections.
Myeloblasts can also infiltrate the central nervous system (CNS), bones, skin, liver, spleen, lymph nodes, and testicles.
Causes of AML
It is still unclear as to what causes AML. It is important to remember that no one is to blame for the disease. There are certain factors that may increase the likelihood of getting AML.
Environmental factors
Exposure to the following may increase the chance of getting AML:
- very high dose of radiation
- benzene
- certain types of chemotherapy drugs
Genetic factors
Genetic syndromes associated with developing AML include:
- Down syndrome (trisomy 21). Children with Down syndrome are at 10-20 times greater risk of developing AML.
- Familial monosomy 7
- Fanconi anemia (FA). This is an inherited anemia that makes it difficult for the bone marrow to produce healthy blood cells.
- Dyskeratosis congenita. People with this disorder are at risk of bone marrow failure and leukemia.
- Bloom syndrome. This is a rare disorder caused by mutations in the BLM gene.
- Neurofibromatosis Type 1 (NF-1). Children with NF-1 are at increased risk of JMML.
- Noonan syndrome. Children with this syndrome are at increased risk of JMML.
- Severe congenital neutropenia (Kostmann syndrome)
- Shwachman-Diamond syndrome (SDS). This is a genetic disorder in which the pancreas and bone marrow cannot function properly.
- Diamond-Blackfan Anemia (DBA). This is a bone marrow disorder that results in a shortage of red blood cells.
- Congenital amegakaryocytic thrombocytopenia. This rare inherited disorder of the bone marrow requires a bone marrow transplant.
- CBL germline syndrome (particularly in JMML)
Acquired syndromes
- severe aplastic anemia, a rare disease that occurs when the bone marrow does not produce enough blood cells.
- paroxysmal nocturnal hemoglobinuria, a rare disease marked by the destruction of red blood cells, impaired bone marrow function, and blood clots.
- amegakaryocytic thrombocytopenia, a blood disorder in which a person has a low number of platelets.
- acquired monosomy 7