Sperm chromosome studies in an infertile man with partial, complete asynapsis of meiotic bivalents.

Meiotic and sperm chromosome studies were carried out in two semen samples from an infertile man with a 46,XY karyotype, oligoasthenoteratozoospermia and abundant exfoliation of spermatogenic cells. Meiotic preparations showed partial, complete asynapsis in a large proportion of metaphase I figures observed, and absence of metaphase II figures, while 24 of the 30 sperm chromosome karyotypes analysed were normal. The remaining sperm karyotypes were as follows: one with structural abnormalities, one with both structural abnormalities and hypohaploidy and four with hypohaploidy. The total frequency of chromosomal abnormalities (6.7%) is similar to that obtained by us in normal men (10.9%). The frequency of spermatozoa with structural abnormalities (6.7%) was not significantly different from that obtained by us in normal men (6.9%). These results suggest that, in some cases, asynaptic spermatogenic cells do not proceed further than metaphase I and only normal germ cells continue spermatogenesis.