Assessing t(6;11)(q27;q23) and Tetrasomy 21 in Down Syndrome Patient: Cytogenetic Implications in Acute Myeloid Leukemia Pathogenesis.

This case report presents the findings of a genetic analysis using conventional cytogenetics and fluorescence in situ hybridization (FISH) to investigate a chromosomal abnormality in a patient with developmental delay and dysmorphic features. The patient was diagnosed with a 48,XY,t(6;11)(q27;q23) translocation and tetrasomy 21. Chromosomal analysis is essential for the diagnosis and risk stratification of all leukemia patients. Not surprisingly, racial differences in chromosomal aberrations (CA) in hematological malignancies could be found, and CA incidence in leukemia might change over time, possibly due to environmental and lifestyle changes. The t(6;11)(q27;q23) translocation is a significant chromosomal rearrangement linked to acute leukemia, particularly acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). This translocation disrupts normal hematopoietic processes by fusing the KMT2A (MLL) gene on 11q23, a master regulator of gene transcription with the MLLT4 (AF6) gene on 6q27, leading to oncogenic transformation and aggressive disease progression. Conventional cytogenetic analysis revealed the presence of an additional chromosome 21 and a translocation between chromosomes 6 and 11, which were further confirmed by FISH. This case highlights the significance of cytogenetic techniques in identifying complex chromosomal disorders and provides insights into the clinical implications of such abnormalities.