[Clinical and experimental study of a multiple myeloma case with low hypodiploidy]

To report the clinical and laboratory characterization of a case of multiple myeloma with low hypodiploid complex karyotyptic abnormalities.Cytogenetic examination of bone marrow performed by 24 h culture method. R-banding technique was used to analyze the karyotype. Interphase fluorescence in situ hybridization (FISH) was performed using chromosome probes such as 13q14, p53, Rb1, 1q21 and IgH/CCND1. The DNA content was detected by flow cytometry.Chromosome analysis revealed complex chromosomal rearrangement. Five cells had a low hypodiploid karyotype with 35 chromosomes. Three cells had the duplication of the low hypodiploid karyotype. Four cells had a normal karyotype. Monosomy 1, 13, 14, 17 and a mark chromosome 1 derived from chromosome 11 resulting in the amplication of CCND1 gene were confirmed by interphase FISH. Flow cytometric analysis displayed a low hypodiploid peak with the DNA index of 0.8426.These results indicated that the low hypodiploidy is a rare abnormality in multiple myeloma. Interphase FISH is a reliable method for detecting molecular abnormalities in multiple myeloma.