Philadelphia chromosome

(FIH-luh-DEL-fee-uh KROH-muh-some)

An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it. Bone marrow cells that contain the Philadelphia chromosome are often found in chronic myelogenous leukemia.

Philadelphia chromosome; three-panel drawing shows a piece of chromosome 9 and a piece of chromosome 22 breaking off and trading places, creating a changed chromosome 22 called the Philadelphia chromosome. In the left panel, the drawing shows a normal chromosome 9 with the abl gene and a normal chromosome 22 with the bcr gene. In the center panel, the drawing shows chromosome 9 breaking apart in the abl gene and chromosome 22 breaking apart below the bcr gene. In the right panel, the drawing shows chromosome 9 with the piece from chromosome 22 attached and chromosome 22 with the piece from chromosome 9 containing part of the abl gene attached. The changed chromosome 22 with bcr-abl gene is called the Philadelphia chromosome.

Philadelphia chromosome. A piece of chromosome 9 and a piece of chromosome 22 break off and trade places. The bcr-abl gene is formed on chromosome 22 where the piece of chromosome 9 attaches. The changed chromosome 22 is called the Philadelphia chromosome.

2008-09-29