Most people with CML have a gene mutation (change) called the Philadelphia chromosome.
Every cell in the body contains DNA (genetic material) that determines how the cell looks and acts. DNA is contained inside chromosomes. In CML, part of the DNA from one chromosome moves to another chromosome. This change is called the “ Philadelphia chromosome.” It results in the bone marrow making an enzyme, called tyrosine kinase, that causes too many stem cells to become white blood cells (granulocytes or blasts).
The Philadelphia chromosome is not passed from parent to child.