A study of meiotic segregation of chromosomes in spermatozoa of translocation carriers using fluorescent in situ hybridisation.

In the infertile male population, there is a 2-20-time higher probability of having a structural chromosomal abnormality than in general population. Generally, these men have a normal phenotype but they can have sperm abnormalities. As they can produce a variable proportion of unbalanced gametes, it is important to evaluate the percentage of unbalanced chromosomal spermatozoa to assess the risk of injecting a chromosomally unbalanced gamete during ICSI procedure. We report here the meiotic segregation analysis of chromosomes in spermatozoa of 12 men with a balanced reciprocal translocation and 4 men with a Robertsonian translocation using a fluorescent in situ hybridisation analysis. The frequencies of normal or balanced spermatozoa ranged from 34.4% to 49.1% in balanced reciprocal translocation carriers. For Robertsonian translocation, the frequencies of normal or balanced spermatozoa ranged from 78.4% to 91.2%. These analyses allow us to define the orientation of genetic counselling according to the results of meiotic segregation obtained. As a last resort, it could then be discussed of the possibility of having recourse to donor spermatozoa or adoption.