CHROMOSOME-21 DETECTION IN HUMAN OOCYTE FLUORESCENCE IN-SITU HYBRIDIZATION - POSSIBLE EFFECT OF MATERNAL AGE

Purpose: The purpose of this study was to evaluate, among 100 uncleave d oocytes, the incidence of numerical and structural chromosome 21 and X abnormalities and to analyze the influence of various factors, such as in vitro (IVF) indications, follicle stimulation protocols, and wo men's age. Methods: We investigated 150 uncleaved oocytes from 128 pat ients after art IVF attempt. After cytogenetic analysis (Giemsa) 100 o ocytes (66%) were selected for fluorescence in situ hybridization (FIS H). Fluorescent probes for human chromosomes X and 21 were used simult aneously according to standard procedures for their hybridization and detection. Results and Conclusions: We analyzed by the FISH protocol 1 00 metaphase II oocytes with 22 to 25 chromosomes. Our results demonst rate a high rate of disomy for chromosome 21 in human oocytes. Among t hem, eight were disomic (8%) and three were nullosomic (3%) for chromo some 21. Only one disomy of chromosome X was noted. The various indica tions of IVF and the different folliculogenesis stimulating protocols did not seem to influence the results but suggested a correlation betw een the maternal age and the aneuploidy rate of chromosome 21.