A patient with myelodysplastic syndrome studied by GTG-banding and fluorescent in situ hybridization (FISH).

Molecular cytogenetics using fluorescent in situ hybridization (FISH) is an extremely useful adjunct technique to conventional cytogenetics via GTG-banding. The present paper illustrates the utility of FISH by describing a patient with myelodysplastic syndrome (MDS) who was initially studied using GTG-banding and whose bone marrow was found to be populated with hyperdiploid cells. FISH was used to delineate the numerical and structural chromosomal abnormalities. It revealed the presence of trisomy 8 and determined that the previously unidentifiable marker chromosome was of chromosome 10 origin. Although trisomy 8 is a frequent finding in MDS, the structural chromosomal abnormality of chromosome 10 as reported here is not a common finding.