Fluorescence in-situ hybridization analysis of chromosomal constitution in spermatozoa from a mosaic 47,XYY/46,XY male.

Sex-chromosome mosaicism in spermatozoa from a mosaic 47,XYY[20%]/46, XY[80%] male with fertility problems was assessed using triple-probe fluorescence in-situ hybridization (FISH) studies. Chromosome-specific probes for X, Y and 18 were used, and the possible outcomes were deduced. In normal haploid spermatozoa of the patient and a normal 46,XY male control, the X:Y ratio was close to 1:1. There was a significant difference in the total incidence of karyotypically abnormal spermatozoa between the patient and the 46, XY male control (2.31% versus 1.46%, P < 0.0001). The incidence of some types of disomic spermatozoa X+Y+18 (24,XY) and X+18+18 (24,X, +18), or diploid X+Y+18+18 (46,XY) spermatozoa was significantly increased in the patient's semen sample. There was, however, no significant difference in the incidence of disomic Y+Y+18 (24,YY) spermatozoa. Because the majority of the patient's spermatozoa was karyotypically normal, the aetiology of his fertility problems was unclear. These results add to the growing body of information regarding chromosome abnormalities in spermatozoa from men who are mosaic for sex chromosome abnormalities. In these men, FISH analysis of spermatozoa may be warranted to determine the relative percentages of abnormal cells, and to determine if in-vitro fertilization with preimplantation genetic diagnosis may increase the likelihood of a successful pregnancy.