ABSTRACT
<p><b>OBJECTIVE</b>To analyze the numerical aberration rate of X, Y and chromosome 18 in sperms from an oligozoospermic male with mosaic trisomy 18 and to perform preimplantation genetic diagnosis (PGD) for the couple.</p><p><b>METHODS</b>G-banding and fluorescence in situ hybridization (FISH) were performed on metaphase chromosome. Sperm was analyzed in three-color FISH with a probe mixture containing CEP18, CEPY and Tel Xq/Yq. A healthy man with normal semen parameters was used as control.</p><p><b>RESULTS</b>Significant difference in the rates of disomy for chromosome 18 (0.63% vs. 0.16%) and the gonosomes (0.945% vs. 0.35%) and diploidy (0.87% vs. 0.31%) was found in the spermatozoa between the patient and the control. After four embryos were biopsied in one PGD cycle, two embryos with XY1818 and XX1818 were selected for implanting and clinical pregnancy was ongoing.</p><p><b>CONCLUSION</b>Sperm-FISH allows further understanding of aneuploidy rate and accurate genetic counseling. FISHPGD was effective for patient with mosaic trisomy 18.</p>