A cryptic deletion in 5q31.2 provides further evidence for a minimally deleted region in myelodysplastic syndromes

Victorian Cancer Cytogenetics Service, St. Vincent's Hospital (Melbourne), Fitzroy, VIC, Australia.
Cancer Genetics (Impact Factor: 2.98). 04/2011; 204(4):187-94. DOI: 10.1016/j.cancergen.2011.02.001
Source: PubMed


Recurrent deletions of 5q in myeloid malignancies encompass two separate regions: deletion of 5q33, which is associated with the 5q− syndrome and haploinsufficiency of RPS14, and deletion of a more proximal locus at 5q31. We present a case with a cryptic 1.3 Mb deletion in 5q31.2 identified by array comparative genomic hybridization that places the proximal boundary of the deletion proximal and close to the candidate EGR1 gene. The patient was diagnosed initially with a myelodysplastic syndrome, with a del(20)(q11.2q13.3) as the sole abnormality identified by karyotyping. The patient progressed to acute myeloid leukemia with no change to the G-banded karyotype. The 1.3 Mb deletion on the long arm of one chromosome 5 was confirmed to have been present both at presentation with myelodysplastic syndrome and at transformation. This is an interesting case because there are few array studies identifying cryptic 5q deletions, and the study of these small deletions helps to refine the common deleted region. This case, together with previously published studies, suggests that the proximal boundary of the common deleted region may lie within the KDM3B gene.

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    • "However, the 5q deletions are highly variable in size and include two different genomic regions, namely, deletions of chromosome band 5q31, encompassing the EGR1 gene, and deletions of bands 5q32 and 5q33 involving haploinsufficiency of RPS14. Molecular karyotyping enables accurate identification of both loci of the 5q deletions, which can be missed when applying only traditional metaphase karyotyping and FISH [MacKinnon et al., 2011]. Furthermore, normal karyotypes are found in 50–60% of the patients, for whom there are no molecular tests to distinguish MDS from benign bone marrow cell diseases making monitoring disease progression in these patients difficult. "
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