Chromosome analysis of human spermatozoa from an oligoasthenozoospermic carrier for a 13;14 Robertsonian translocation by their injection into mouse oocytes.

We present a case of a 46,XY der(13;14) Robertsonian translocation carrier whose spermatozoa were karyotyped after injection into mouse oocytes. Fresh semen samples as well as recovered samples were used. There was no significant difference in the survival rate of mouse oocytes (fresh: 78.1% versus frozen: 81.7%), activation rate (fresh: 84.0% versus frozen: 90.6%), fertilization rate (fresh: 72.0% versus thawing of frozen: 76.5%) between fresh or frozen spermatozoa. Metaphase chromosome spreads from 45 spermatozoa were analysed. The frequency of spermatozoa that were chromosomally unbalanced with respect to the translocation was 8.9%, and the frequency of abnormalities unrelated to translocation was 4.4%. An excess of spermatozoa with balanced chromosomes was observed: compared with normal, 23 (51.1%) versus 16 (35.6%) respectively; but this segregation difference was not statistically significant (chi(2) = 0.9, P > 0.3). After genetic counselling with the carrier and his partner, intracytoplasmic sperm injection treatment was performed. Healthy female and male infants were delivered at 36 weeks gestation via a Caesarean section. Both babies were carriers for the balanced Robertsonian translocations detected for prenatal diagnosis at 16 weeks gestation. The present study demonstrates that patients can be given further information about the proportion of the spermatozoa which carry a chromosomal abnormality.