Preimplantation genetic diagnosis outcomes and meiotic segregation analysis of robertsonian translocation carriers.

OBJECTIVE: To investigate the meiotic segregation patterns of cleavage-stage embryos from robertsonian translocation carriers and aneuploidy of chromosome 18 according to meiotic segregation patterns.

DESIGN: Retrospective study.

SETTING: Infertility center and laboratory of reproductive biology and infertility.

PATIENT(S): Sixty-two couples with robertsonian translocation carriers.

INTERVENTION(S): One blastomere was biopsied from embryos and diagnosed with the use of fluorescence in situ hybridization (FISH). Translocation chromosomes were analyzed with the use of locus-specific and subtelomeric FISH probes. Aneuploidy of chromosome 18 was assessed simultaneously with translocation chromosomes.

MAIN OUTCOME MEASURE(S): Preimplantation genetic diagnosis (PGD) outcomes, meiotic segregation patterns of robertsonian translocation, and aneuploidy of chromosome 18 depending on meiotic segregation patterns.

RESULT(S): Two hundred seventy embryos of 332 transferrable embryos were transferred in 113 cycles, and 27 healthy babies were born. The alternate segregation was significantly higher in male carriers than in female carriers (43.9% vs. 29.9%, respectively), and adjacent segregation was higher in female carriers than in male carriers (44.7% vs. 38.7%, respectively). Aneuploidy of chromosome 18 was significantly increased in 3:0-segregated or chaotic embryos. Forty-seven alternate embryos were excluded from embryo replacement owing to aneuploidy of chromosome 18.

CONCLUSION(S): In carriers of robertsonian translocation, meiotic segregation showed differences between men and women. Frequent meiotic errors caused by premature predivision or nondisjunction and less stringent checkpoint in women might cause such differences between sexes. Aneuploidy of chromosome 18 might be influenced by meiotic segregation of translocation chromosomes. Factors that cause malsegregation, such as 3:0 or chaotic segregation, seem to play a role in aneuploidy of chromosome 18.