Marker Chromosomes in Korean Patients: Incidence, Identification and Diagnostic Approach

The identification of marker chromosomes is important for genetic counseling. However, the origin or composition can rarely be defined with conventional cytogenetic technique alone. In this study, we investigated the incidences and types of marker chromosomes in Korean patients and attempted to establish a cost-effective diagnostic approach for marker chromosomes. We reviewed the karyotypes of 2,984 patients that were requested for the cytogenetic analysis between 1997 and 2003 at the Samsung Medical Center. Ten marker chromosomes were found and identified using fluorescent in situ hybridization (FISH). Among the ten marker chromosomes, six were supernumerary marker chromosomes (SMCs) and the rest were marker chromosomes in Turner syndrome (TS). The incidence of SMCs was 2.01/1,000, slightly higher than that previously reported. Five of six SMCs were satellited marker chromosomes. Three bisatellited marker chromosomes originated from chromosome 15 and two from chromosome 22. The origin of one SMC could not be identified. All marker chromosomes in TS originated from X- or Y chromosome. The application of FISH is indispensable to identify marker chromosomes, and the appropriate selection of probes is necessary for cost-effective analysis. For analyzing satellited marker chromosomes, application of probes for chromosome 15 followed by those for chromosome 22 is recommended and in cases of TS, probes for sex chromosomes should take precedence.

A Case Report of t(8;22) with Additional Chromosomal Defects in Bone Marrow Involvement of B Cell Type Diffuse Large Cell Lymphoma / 대한임상병리학회지

The t(8;14)(q24;q32) translocation or its variants, t(2;8)(p12;q24) and t(8;22)(q24;q32) are classically seen in Burkitt's lymphoma, but are also found in diffuse large cell lymphoma (DLCL). Burkitt's lymphoma is very rare in Korea and t(8;14) or its variants have not been reported. We report a case of DLCL (B-cell type) with t(8;22) and additional chromosomal abnormalities. The patient, 45-year-old male, complained intermittent abdominal pain. The histologic examination of sigmoid colon revealed DLCL. Lymphoma cells were counted about 58.8% of all nucleated cells in bone marrow aspiration and showed surface membrane immunoglobulin positivity. Chromosome study of bone marrow aspiration was done using high resolution banding technique. The karyotype was 47,XY,+1,del(6)(q21),t(8;22)(q24;q11),del(13)(q31),der(14)t(1;14)(q23;q32)?, del(17)(p11) in all of the nineteen metaphases which were analyzed. Although he was treated by chemotherapy and radiotherapy, lymphoma cells were increased in peripheral blood and he expired.