The Philadelphia chromosome (Ph) is the genetic marker for CML that forms the Bcr-Abl gene due to the reciprocal translocation [t(9;22)(q34;q11)] of chromosome 9 containing the Abl gene and chromosome 22 which contains the Bcr gene [4, 5]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.