MOLECULAR CYTOGENETIC DIAGNOSTICS IN SPERM

Among other factors contributing to male infertility, chromosomal anom alies are a frequent finding. Investigating 440 males with reduced spe rm counts (<20 x 10(6)/mL) we found 19 males with chromosome abnormali ties (aneuploidies and translocations). This frequency of chromosomal aberrations (4.3%) is much higher than in the normal population. We we re able to investigate sperm nuclei from seven out of these 19 men wit h molecular cytogenetic methods. There were two carriers of Robertsoni an translocations, two had a constitutional reciprocal translocation a nd three were XYY males. In addition, one other man with a long histor y of infertility and a marker chromosome 15 was included. Using fluore scence in-situ hybridization, it was possible to investigate a great n umber of sperm nuclei in each case. Each translocation case showed a s pecific mode of chromosomal segregation; confirming the dependence on chromosomes involved and the individual segregation pattern in each pa tient. The well known elimination of the supernumerary Y-chromosome in XYY males during meiosis was confirmed in our study. Molecular cytoge netic investigations in sperm provide a more reliable risk estimate wi th respect to the possible injection of chromosomally unbalanced sperm during intracytoplasmatic sperm injection and can be valuable in gene tic counselling.