MCQ IN MEDICINE

Detailed explanation-1: -Chronic myeloid leukemia is caused by a rearrangement (translocation ) of genetic material between chromosome 9 and chromosome 22. This translocation, written as t(9; 22), fuses part of the ABL1 gene from chromosome 9 with part of the BCR gene from chromosome 22, creating an abnormal fusion gene called BCR-ABL1 .

Detailed explanation-2: -The Philadelphia (Ph1) chromosome arising from the reciprocal t(9; 22) translocation is found in more than 90% of chronic myeloid leukemia (CML) patients and results in the formation of the chimeric fusion gene BCR-ABL.

Detailed explanation-3: -Chronic myelogenous leukemia (CML) is characterized by the Philadelphia (Ph) chromosome created by the reciprocal translocation t(9:22)(q34; q11), resulting in the chimeric gene breakpoint cluster region (BCR)-Abelson (ABL).

Detailed explanation-4: -Chronic myeloid leukemia (CML) is characterized by the presence of the Philadelphia chromosome (Ph), usually due to a reciprocal translocation, t(9; 22)(q34; q11. 2).

Detailed explanation-5: -Most cases of CML start during cell division, when DNA is “swapped” between chromosomes 9 and 22. Part of chromosome 9 goes to 22 and part of 22 goes to 9. The swapping of DNA between the chromosomes leads to the formation of a new gene (an oncogene) called BCR-ABL.