Question

Which structural chromosomal abnormality is exemplified by the Philadelphia chromosome associated with Chronic Myeloid Leukaemia?

Options

• Translocation

• Deletion

• Duplication

• Inversion

Answer 1

The Philadelphia chromosome represents a translocation in which a segment from chromosome 9 attaches to chromosome 22. This balanced translocation t(9;22) causes the fusion of the BCR and ABL genes, leading to abnormal protein production and Chronic Myeloid Leukaemia. Carriers may appear phenotypically normal but have increased cancer risk.