Cytogenetics of human spermatozoa: what about the reproductive relevance of structural chromosome aberrations?

The purpose was to review and appreciate data on structural sperm chromosome abnormalities obtained after fusion of human spermatozoa with zona-free hamster eggs.

Breaks and fragments are the predominant sperm chromosome aberrations. In contrast to stable alterations, e.g., translocations, inversions, and deletions that will be transmitted unchanged into following cell generations, breaks, fragments, and some rearrangements have a reduced stability. In proliferating cell systems they will soon be eliminated through formation of lagging chromatin and micronuclei. Their relevance lies in a loss of genetic material or disturbance of cell division that may cause cell death. It is reasonable to assume a responsibility of such aberrations for early unrecognized conception loss. However, this interpretation is subject to criticism because an artifactual origin of sperm chromosome breakage cannot be ruled out.

The incidence and relevance of structural sperm chromosome abnormalities will remain at issue unless additional and complementary information is provided. For this purpose, new strategies must be developed because further studies employing hamster eggs according to existing protocols will not help resolve the dilemma.