True regarding Philadelphia chromosome are all of the following except: March2008
Ans. C: Specific for CMLPhiladelphia translocation is a specific chromosomal abnormality that is associated with chronic myelogenous leukemia (CML).It is the result of a reciprocal translocation between chromosome 9 and 22, and is specifically designated t(9;22)(q34;q11). The presence of this translocation is a highly sensitive test for CML, since 95% of people with CML have this abnormality (the remainders have either a cryptic translocation that is invisible on G-banded chromosome preparations, or a variant translocation involving another chromosome or chromosomes as well as the long arm of chromosomes 9 and 22).However, the presence of the Philadelphia (Ph) chromosome is not sufficiently specific to diagnose CML, since it is also found in acute lymphoblastic leukemia (ALL, 25-30% in adult and 2-10% in pediatric cases) and occasionally in acute myelogenous leukemia (AML).
Present in 95% of CML patients
It is the result of a reciprocal translocation
Specific for CML
Designated as t(9;22) (q34;q11)