Comprehensive chromosome FISH assessment of sperm aneuploidy in normozoospermic males

Sperm chromosomal abnormalities impact male fertility and pregnancy outcomes. However, the proportion of sperm with chromosomal abnormalities in normozoospermic men remains unclear. Herein, we evaluated sperm aneuploidy for 23 chromosomes to elucidate its incidence in normozoospermic men.

Sperm from ten normozoospermic donors were obtained from a human sperm bank and analyzed using fluorescence in situ hybridization. The frequencies of nullisomy, disomy, and diploidy were analyzed along with trisomy, triploidy, tetraploidy, and other numerical abnormalities per chromosome and per donor levels.

A total of 248,811 sperm cells were analyzed (average: 24,881 ± 381 cells/donor), of which 246, 658 were haploid, 818 nullisomic, 393 disomic, 894 diploid, 13 triploid, 8 tetraploid, 3 trisomic, and 24 harbored multiple aneuploidies. Among the 22 autosomal and 2 sex chromosomes, the mean frequency of aneuploidy per chromosome was 0.49 ± 0.16%, including 0.33 ± 0.16% for nullisomy and 0.16 ± 0.08% for disomy. The mean frequencies of nullisomy, disomy, and aneuploidy per donor were 0.33 ± 0.13%, 0.16 ± 0.05%, and 0.49 ± 0.13%, respectively. The total frequencies of nullisomy, disomy, diploidy, and aneuploidy per donor were 7.62 ± 3.06%, 3.63 ± 1.12%, 0.36 ± 0.15%, and 11.25 ± 3.05%, respectively.

The dominant chromosome numerical abnormalities in normozoospermic men are nullisomy, disomy, and diploidy. Generally, the frequency of nullisomy is higher than that of disomy. The disomy or nullisomy frequencies for each chromosome being gained or lost were not unified and varied; some chromosomes (e.g., chromosomes 21 and 22 and sex chromosomes) are more prone to disomy while some others (e.g., chromosome 3) are more prone to nullisomy.