Philadelphia chromosome

An abnormality called a translocation where part of chromosome 9 is switched with a part of chromosome 22. This makes chromosome 22 shorter than normal. This type of chromosome abnormality happens in our cells during our lifetime, it is not inherited from our parents.

The Philadelphia chromosome is found in the leukemia cells of almost all people diagnosed with chronic myelogenous leukemia. Some people with acute lymphoblastic leukemia may also have the Philadelphia chromosome in their leukemia cells.