Philadelphia chromosome
46,XY,t(9;22)(q34;q11.2)
Also known as: t(9;22), BCR-ABL1, CML
46,XY,t(9;22)(q34;q11.2) is the Philadelphia chromosome, a reciprocal translocation between chromosomes 9 and 22. The resulting BCR::ABL1 fusion gene defines chronic myeloid leukemia.
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der(9)
9
der(22)
22
What the notation means
46- total chromosome count (the normal human number)
XY- sex chromosomes: one X, one Y (usual male karyotype)
t(9;22)(q34;q11.2)- a reciprocal TRANSLOCATION: chromosomes 9 and 22 break (at 9q34 and 22q11.2) and swap the pieces beyond those breaks, giving two derivative chromosomes der(9) and der(22)
Clinical notes
t(9;22), Philadelphia chromosome
The reciprocal t(9;22)(q34;q11.2) fuses BCR (22) with ABL1 (9), creating BCR::ABL1, the hallmark of chronic myeloid leukemia (also some ALL). Target of imatinib and other tyrosine-kinase inhibitors.