10, 15 reciprocal translocation in an infertile man: ultrastructural and fluorescence in-situ hybridization sperm study: case report

BACKGROUND: Peculiar sperm defects are described in a sterile man heterozygous for a balanced translocation t(10;15) (q26;q12). As this structural reorganization was absent in the parents, the translocation must have appeared de novo in the present patient. METHODS: Spermatozoa were analysed under light and transmission electron microscopy (TEM). Fluorescence in-situ hybridization (FISH) was performed on the lymphocyte karyotype. Aneuploidy frequencies of chromosomes 18, X and Y in sperm nuclei, not involved in the translocation, were investigated using three-colour FISH. Dual- colour FISH was used to evaluate segregation of chromosomes 10, 15 in decondensed sperm nuclei. Moreover, three-colour FISH, using telomeric probes for chromosomes 10, 15 was performed in order to distinguish balanced and unbalanced gametes. RESULTS AND CONCLUSIONS: Overall, structural characteristics indicate general immaturity of the germinal cells. FISH sperm analysis detected an increase in chromosome 18 disomy (0.81%) suggesting an interchromosomal effect. A high frequency of diploidies, particularly 18,18,X,X and 18,18,X,Y, was also found. FISH segregation analysis for chromosomes 10, 15 indicated that 32.8% were balanced gametes, whereas 68.2% were unbalanced. Taken together, these data demonstrate in a male carrier of a reciprocal translocation t(10;15) the presence of diffuse ultrastructural sperm alterations and a high frequency of sperm aneuploidies. The existence of a correlation among these factors is proposed.