Incidence of sex chromosome abnormalities in spermatozoa from patients entering an IVF or ICSI protocol.

OBJECTIVE: The objective of this study was the determination of sex chromosome aneuploidy frequency in spermatozoa from patients included in an in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI) protocol.

METHODS: Spermatozoa from nineteen patients, including patients with normal seminal parameters according to World Health Organization (WHO) criteria and patients exhibiting abnormal seminal parameters, were analyzed by dual color fluorescence in situ hybridization (FISH) for aneuploidies of the X and Y chromosomes. Our technique, using only probes for sex chromosomes and not for autosomes, does not discriminate between hyperhaploid and diploid sperm nuclei. The results were analyzed in two different ways: in relation to the semen status, denoted normal or abnormal and with regard to the ability of the sperm to fertilize oocytes when IVF or ICSI was performed.

RESULTS: Abnormal semen showed a significant increase in the overall rate of sperm nuclei with XY, XX and YY sex chromosome complements, 1.59% compared to normal semen, 0.78% (p<0.02). Semen shown to be able to fertilize oocytes only by ICSI showed a higher incidence of XY-bearing spermatozoa, 1.26%, compared to semen able to fertilize oocytes by conventional IVF, 0.37% (p<0.001). The incidence of XX-or YY-bearing sperm nuclei was also significantly elevated in the ICSI group (0.25% XX, 0.50% YY) (p<0.02) as compared to the IVF group (0.06% XX, 0.16% YY).

CONCLUSIONS: We concluded that infertile men requiring ICSI treatment showed a higher incidence of sex chromosome aneuploidy, due to meiosis I and II nondisjunction, in their spermatozoa as compared to men requiring IVF for reasons of predominantly female infertility.