FISH analysis of chromosome X, Y and 18 abnormalities in testicular sperm from azoospermic patients.

BACKGROUND Sperm extracted from testicular biopsies of azoospermic men can successfully be used for ICSI. The concern exists that testicular sperm from azoospermic men suffering from severe testicular failure may have a higher frequency of aneuploidy, which may lead to an increased risk for chromosomally abnormal offspring. METHODS Testicular sperm from patients showing spermatogenic failure (n = 17) and from patients with normal spermatogenesis (n = 26) were analysed by fluorescence in-situ hybridization (FISH). Numerical chromosomal abnormalities for chromosomes X, Y and 18 were evaluated by FISH in a total of 1697 testicular sperm derived from 43 azoospermic patients. RESULTS No difference was observed between the frequency of chromosomal abnormalities in testicular sperm from patients with normal spermatogenesis (5.6%) and from patients with spermatogenic failure (8.2%). However, the frequency of aneuploidy for chromosome 18 was higher in the group of azoospermic patients with spermatogenic failure than in the group with normal spermatogenesis (3.2 versus 1.3%). Within the obstructive group, sex chromosome aneuploidy (4.5%) occurred more frequently than chromosome 18 aneuploidy (1.3%; P < 0.001). Among testicular sperm derived from patients with spermatogenic failure, sex chromosomal aneuploidy (5.8%) was similar to that for chromosome 18 (3.2%). CONCLUSIONS So far, no difference in the total frequency of chromosomal abnormalities has been observed between patients with normal spermatogenesis and patients with severe testicular failure. However, aneuploidy for chromosome 18 was higher in the group with spermatogenic failure.