Chromosome abnormalities in spermatozoa of patients with azoospermia and normal somatic karyotype

Since epididymal and testicular spermatozoa of azoospermic patients are frequently used for intracytoplasmic sperm injection (ICSI), many studies have been carried out to evaluate their karyotype. This article will review all published data on this topic. In most of the studies, spermatozoa have been retrieved from the testis or the epididymis of patients with nonobstructive (NOA) or obstructive (OA) azoospermia, respectively. Sperm aneuploidy has been evaluated by fluorescence in situ hybridization using probes for sex chromosomes and an array of autosomes. A significantly higher sperm aneuploidy rate has been reported in patients with NOA and OA compared to ejaculated spermatozoa, mainly for sex chromosomes. The magnitude of the increase varies between studies, probably because of the heterogeneity of case selection as well as of the methodology employed. The majority of the studies reported that patients with NOA have a greater sperm aneuploidy rate compared to OA. The greater frequency of sperm aneuploidy in azoospermic patients increases the risk of transmitting a karyotype abnormality to the offspring generated by ICSI.