Objective: To determine the karyotype of a case with a history of spontaneous abortion and terminal deletion by using of conventional G-banding method and search the cause of insertional translocation of chromosomal terminal region.
Methods: Fluorescence in situ hybridization (FISH) technique was performed to analyze the case by using whole chromosome 7 painting probe and subterminal probe of 7q36-->qter which was generated by chromosome microdissection technique.
Results: The case was a carrier with a very rare insertional translocation involving chromosomes 1 and 7. The region of chromosome 7q36-->qter was not inserted into chromosome 1. The abnormal chromosome was inherited from her mother.
Conclusion: The present authors provided an experiment evidence that in this case the chromosome insertional translocation including the terminal region was still a three breakage rearrangement and the terminal deletion found by cytogenetics should be an interstitial deletion. Combining with chromosome microdissection, FISH technique is a powerful diagnostic method for detecting the chromosome structural abnormality.