An 18-year-old man is diagnosed with acute promyelocytic leukemia (APL, AML-M3). He develops bleeding and his coagulation profile shows PT 22s, APTT 48s, fibrinogen 80 mg/dL, D-dimer markedly elevated. The pathognomonic cytogenetic abnormality in APL is:

• A t(9;22)(q34;q11) — BCR-ABL1
• B t(8;14)(q24;q32) — MYC-IGH
• C inv(16)(p13q22) — CBFB-MYH11
• D t(15;17)(q24;q21) — PML-RARA ✓

Explanation

APL is characterized by t(15;17), which fuses the PML gene (chromosome 15) with the RARA gene (chromosome 17), creating the PML-RARA fusion protein. This fusion protein blocks myeloid differentiation at the promyelocyte stage and is specifically targeted by ATRA (all-trans retinoic acid) and arsenic trioxide (ATO), which degrade the fusion protein and induce differentiation. t(9;22) is CML/B-ALL. t(8;14) is Burkitt lymphoma. inv(16) is AML-M4Eo.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.