Product Description:
A 35 year old male with eosinophilia and acute venous embolism was referred to our laboratory for chromosome analysis on a bone marrow specimen. Conventional cytogenetic analysis revealed add (19)(p13.3) in all 20 cells analyzed. The add(19)(p13.3) did not resemble any recurrent cancer associated rearrangement involving 19p13. FISH studies using E2A Breakapart Probe on 19p13.3 were negative for a rearrangement of E2A. Since the abnormality was observed in every cell analyzed, it was uncertain as to whether it was an acquired or constitutional abnormality. A peripheral blood specimen was requested for chromosomal analysis on stimulated cells. At this time the hematologist reported that the patient had poor cognitive functions. Cytogenetic results revealed the presence of the add(19) in every cell analyzed. To curtail the task of doing multiple FISH studies for identification of the unknown segment on add (19), microarray was performed utilizing the 180K custom oligonucleotide array. The investigations revealed an interstitial 271Kb copy number loss in 19p13.3 and a 12.7Mb copy number gain of chromosome region 2q11.2q13. The additional segment of 19 was thus characterized as part of chromosome 2. The interstitial deletion within 19p13.3 detected by microarray was too small to be microscopically visible. The bone marrow nomenclature was revised and the karyotype was described as 46,XY,det(19)del(19)(p13.3p13.3)ins(19;2)(p13.3;q11.2q13)c[20]. Although microarray studies are now routinely performed among majority of the cases examined in the genetics clinics for developmental, physical and/or mental predicament, the use of this technique for classification of unidentifiable segments in neoplasia is not very common because of the expenses involved. However, in situations where multiple FISH investigations may be required as seen in our current case study, the use of microarray may be required as seen in our current case study, the use of microarray may not only be economical but more informative in identifying other possible subtle abnormalities.
