Meiotic segregation study of a novel t(3;6)(q21;q23) in an infertile man using fluorescence hybridization (FISH)

Male carriers with balanced reciprocal translocations can produce a variable proportion of unbalanced gametes resulting in reproductive failures. The presence of a structural rearrangement may induce an interchromosomal effect. This is characterized by abnormal bivalents not involved in the reorganization thereby yielding non-disjunction, which would present as aneuploid spermatozoa for these chromosomes. In the present case report segregation analysis of the sperm and investigationof interchromosomal effect were carried out using cytogenetic and fluorescence in situ hybridization (FISH) analysis on blood lymphocytes. The karyotype of the patient was 46,XY,t(3;6)(q21;q23). During sperm segregation analysis a total of 2,002 sperms were evaluated, of which 46.8% showed normal/balanced (alternate segregation mode) and 53.2% of sperm showed an abnormal signal pattern. A significant difference in the frequency of the estimated number of chromosome anomalies was observed in the translocation carrier when compared to the normozoospermic group (P < 0.0001) and the oligozoospermicgroup (P < 0.0001). Meiotic segregation analysisof sperm together with aneuploidy assessment for X, Y, and 17chromosomes using FISH allows for the determination of areproductive prognosis in male balanced translocation carriersand can be used for appropriate genetic counselin