Abstract
Del(20q) is the most frequently detected large structural genetic mosaicism alteration in the healthy aging population, occurring in approximately 0.1% of older persons. Age‐related clonal hematopoiesis of copy number variations (CNVs) is linked to an increased risk of hematologic malignancies, but the clinical impact of hematopoietic stem cells (HSCs) harboring such CNVs, such as del(20q), is not clearly understood. Here, we report an acute myeloid leukemia (AML) patient with known del(20q) who acquired donor‐derived del(20q) after allogeneic hematopoietic stem cell transplantation (HSCT). The HSCs with del(20q) engrafted and expanded over time, but the patient did not clinically progress to myeloid neoplasm. Although donor‐derived del(20q) from a healthy donor has been reported previously, our case is the first to review the clonal dynamics of a del(20q) clone and its post‐transplantation impact. Since recurrent hematology neoplasm‐associated CNVs, including del(20q), may not be rare among aged HSCT donors, identifying the origin of such a CNV is necessary for clinical decisions when clonal abnormality appears after HSCT, even in recipients who previously had the same abnormality.
Highlights
Deletion of 20q is a recurrent cytogenetic abnormality seen in a broad spectrum of hematologic malignancies
Conventional karyotyping was analyzed in 24 hours without mitotic stimulation bone marrow (BM) aspirate samples
We performed fluorescence in situ hybridization (FISH) study for detection of del(20q) on an ali‐ quot of hematopoietic stem cell collection (HSCC) to determine the clinical significance of reappeared del(20q); 8% of cells (16/200) from the HSCC showed the deletion (Figure 2)
Summary
Deletion of 20q is a recurrent cytogenetic abnormality seen in a broad spectrum of hematologic malignancies. Del(20q) is observed in 5%‐7% of myelodysplastic syndrome (MDS), 1%‐2% of acute my‐ eloid leukemia (AML), and 10% of myeloproliferative disease.[1,2,3]. Frequently observed in myeloid neoplasm, del(20q) is in‐ sufficient as definitive evidence for diagnosis of myeloid neoplasm.[4] Del(20q) has been suggested as an age‐related clonal hematopoiesis (ARCH),[5] in that it was the most frequently detected large structural genetic mosaicism alteration in a healthy aging population.[6] the prevalence of 20q deletion was more common than that of myeloid neoplasm.[7] ARCH‐related copy number variation (CNV) predicted an increased risk of hematologic malignancy,[8,9] but the clinical signifi‐ cance of hematopoietic stem cell transplantation (HSCT) from a donor with such clonal hematopoiesis remains uncertain. We report the clonal dominance of a donor‐derived del(20q) clone after allogeneic HSCT in an AML patient with known
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