The Effect of Teratozoospermia on Sex Chromosomes in Human Embryos

Abstract

Purpose: The aim of this study is to evaluate the effect of abnormal semen morphology on the frequency of sex chromosomal abnormalities in embryos obtained by ICSI, which represents the first to be studied in Egyptian population.

Methods: Forty-two couples suffering from male infertility due to teratozoospermia were divided into two groups: patients with severe and moderate teratozoospermia (group A and B, respectively). All involved couples were subjected to careful history taking and had a normal clinical examination and karyotype. Females were subjected to hormonal assays, pelvic ultrasound, hysterosalpingography and yielded normal results, while male partners were subjected to computerized semen analysis. Preimplantation genetic diagnosis was performed for all suitably developed embryos including embryo biopsy, fixation of biopsied cells and fluorescent in situ hybridization (FISH) analysis.

Results: Couples included in the two groups were found to be homogenous in terms of age of both partners and duration of infertility. Interpretation of FISH results was performed by evaluation of embryos' chromosomal constitution as regards abnormalities in chromosomes X, Y and 18. Twenty-seven embryos (48.2%) were found chromosomally abnormal in group A, while only 14 embryos (25.0%) were found chromosomally abnormal in group B. Aneuploidies involved only sex chromosomes were tripled in group A embryos when compared to their frequency in group B embryos (26.8% and 8.3%, respectively) with statistically significant difference between the two groups (p=0.002). Monosomies were the most common type of aneuploidy and were significantly higher in group A (14.3%) when compared to group B (3.6%) (p=0.047). Embryos with mosaic abnormalities were more common in group A (12.5%) when compared to group B (3.6%), however not statistically significantly different (p= 0.162). A significant difference between the two studied groups as regards the total number of potentially viable chromosomal abnormalities detected and the potentially viable sex chromosomal aneuploidies detected (p<0.001 and p=0.002), respectively.

Conclusion: The cases with severe teratozoospermia undergoing ICSI treatment can display a higher rate of sex chromosome aneuploidies in their embryos (threefold) than cases with moderate teratozoospermia.

Keywords: FISH; ICSI; aneuploidy; teratozoospermia.

Figure 1

(A) Nuclei of three blastomeres using cytocell aquarius kit (REF: LPA 002) for probe combination; X chromosome centromere, Xp11.1- q11.1 (DXZ1) Green, Y chromosome centromere, Yp11.1-q11.1 (DYZ3) Red and 18 chromosome centromere, 18p11.1- q11.1 (D18Z1) Blue, each showing a single green, a single red and two blue signals representing a normal male embryo. (B) Nuclei of two blastomeres each showing two green and two blue signals representing a normal female embryo. (C) Nuclei of four trophoblasts each with two blue signals, two green signals and one red signal representing an XXY embryo. (D) A nucleus of a blastomere showing two blue signals and a single green signal representing a Turner syndrome embryo (monosomy X).

Figure 2

Frequencies of different types of aneuploidies detected in group A and B.

Figure 3

Frequencies of Ploidies detected in group A and B.

Figure 4

(A) Nuclei of multiple trophoblasts showing multiple diploid trophoblasts (two blue and two green signals) and a single haploid trophoblast (a single blue and green signal) representing a mosaic diploid-haploid embryo. (B) Nuclei of two trophoblasts showing a tetraploid trophoblast (four red, four green and four blue signals) and a triploid trophoblast (three red, three green and three blue signals).

Figure 5

Nuclei of two blastomeres representing an aneuploid mosaic embryo with one cell showing XXXXY signal (two blue, four green and a single red signal) while the other showing XXY signal (two blue, two green and a single red signal).