XL 20q12/20qter plus consists of an orange-labeled probe hybridizing to the PTPRT gene region at 20q12 and a green-labeled probe hybridizing to a region at 20q13.3.

Probe maps for selected products have been updated. These updates ensure a consistent presentation of all gaps larger than 10 kb including adjustments to markers, genes, and related elements. This update does not affect the device characteristics or product composition. Please refer to the list to find out which products now include updated probe maps.

Probe map details are based on UCSC Genome Browser GRCh37/hg19, with map components not to scale.

Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell disorders associated with ineffective hematopoiesis and peripheral blood cytopenias. Approximately 40% of MDS cases are progressing to acute myeloid leukemia. In about 50% of de novo MDS, cytogenetic aberrations are observed; deletions are predominant, translocations are rare. Recurrent abnormalities are del(5q), monsomy 7, del(7q), del(20q), del(17p) and del(11q).

A chromosome 20q deletion is seen in about 2% of MDS cases. Patients with a sole del(20q) have a favourable outcome compared to patients with additional abnormalities such as del(5q), del(7q), monosomy 7 and trisomy 8. The majority of patients with del(20q) have an interstitial deletion between 20q11.2 and 20q13.3. In rare cases, the 20q deletion can occur as an isoderivative chromosome ider(20q) with loss of the p-arm of chromosome 20 and partial trisomy of the remaining regions on the q-arm.

Clinical Applications

• Myelodysplastic Syndrome (MDS)
• Acute Myelogenous Leukemia (AML)

XL 20q12/20qter plus hybridized to lymphocytes. One normal interphase and one partial metaphase are shown.

• Kurtin et al (1996) Am J Clin Pathol 106:680-688
• Douet-Gilbert et al (2008) Br J Haematol 143:716-720
• Bacher et al (2014) Br J Haematol 164:822-833