Translations:Types/leukemia/patient/child-aml-treatment-pdq/37/en

CML often begins in an early myeloid blood cell when a certain gene change occurs. A section of genes, that includes the ABL gene, on chromosome 9 changes place with a section of genes on chromosome 22, which has the BCR gene. This makes a very short chromosome 22 (called the Philadelphia chromosome) and a very long chromosome 9. An abnormal BCR-ABL gene is formed on chromosome 22. The BCR-ABL gene tells the blood cells to make too much of a protein called tyrosine kinase. Tyrosine kinase causes too many white blood cells (leukemia cells) to be made in the bone marrow. The leukemia cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. CML is rare in children.