Chromosome analysis of epididymal and testicular sperm in azoospermic patients undergoing ICSI

Although ICSI provides a way of treating azoospermic men, concern has been raised about the potential risk for transmission of genetic abnormalities to the offspring. We quantified the incidence of chromosomal abnormalities in epididymal and testicular sperm retrieved from azoospermic patients undergoing ICSI.

Individual testicular sperm were collected from testicular biopsies with an ICSI pipette, and epididymal sperm were retrieved by microsurgical epididymal sperm aspiration. Samples were processed by fluorescent in-situ hybridization (FISH) for chromosomes 18, 21, X and Y and the results compared with those from normal ejaculated samples.

The overall aneuploidy rate of 11.4% in men with non-obstructive azoospermia was significantly higher (P = 0.0001) than the 1.8% detected in epididymal sperm from men with obstructive azoospermia and also the 1.5% found in ejaculated sperm. No significant difference was found between the epididymal and ejaculated samples. When the chromosomal abnormalities were analysed, gonosomal disomy was the most recurrent abnormality in both obstructive and non-obstructive azoospermic patients, while autosomal disomy was the most frequent in ejaculated sperm.

Sperm of non-obstructive azoospermic men had a higher incidence of chromosomal abnormalities, of which sex chromosome aneuploidy was the most predominant. Genetic counselling should be offered to all couples considering infertility treatment by ICSI with testicular sperm.