CYTOGENETICS OF HUMAN SPERMATOZOA - WHAT ABOUT THE REPRODUCTIVE RELEVANCE OF STRUCTURAL CHROMOSOME-ABERRATIONS

Purpose: The purpose was to review and appreciate data on structural s perm chromosome abnormalities obtained after fusion of human spermatoz oa with zona-free hamster eggs. Results: Breaks and fragments are the predominant sperm chromosome aberrations. In contrast to stable altera tions, e.g., translocations, inversions, and deletions that will be tr ansmitted unchanged into following cell generations, breaks, fragments , and some rearrangements have a reduced stability. In proliferating c ell systems they will soon be eliminated through formation of lagging chromatin and micronuclei. Their relevance lies in a loss of genetic m aterial 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 breaka ge cannot be ruled out. Conclusions: The incidence and relevance of st ructural sperm chromosome abnormalities will remain at issue unless ad ditional and complementary information is provided. For this purpose, new strategies must be developed because further studies employing ham ster eggs according To existing protocols will nor help resolve the di lemma.