Clinical outcomes in carriers of complex chromosomal rearrangements: a retrospective analysis of comprehensive chromosome screening results in seven cases.

OBJECTIVE: To evaluate the clinical outcomes in carriers of complex chromosomal rearrangements (CCRs).

DESIGN: Case series.

SETTING: An institute for reproductive and stem cell engineering.

PATIENT(S): Seven couples with CCRs.

INTERVENTION(S): Assisted reproduction with preimplantation genetic diagnosis (PGD).

MAIN OUTCOME MEASURE(S): PGD results, embryo rating, pregnancy outcomes.

RESULT(S): In cases 1, 2, 3, 4, 5, and 6, each woman underwent one cycle of PGD. Case 7 underwent two PGD cycles. We obtained 51 blastocysts from seven couples with CCR, of which 47 were eligible for biopsy; only 3 (5.9%) were normal/balanced, and 2 (3.9%) conceptions resulted. One healthy baby girl was born (the other was not yet born at the time of publication). Karyotyping revealed that the healthy baby girl was 46,XX. Although the patient with both a balanced translocation and a CCR (case 7) had 12 embryos available for biopsy, all were chromosomally unbalanced. It is interesting that 22 (57.9%) of the total 38 blastocysts were of high quality for type A CCRs, and 2 (15.4%) of the total 13 blastocysts were of high quality for type B CCR at day 6 after fertilization.

CONCLUSION(S): The chances of identifying normal/balanced blastocysts in patients with CCR are <6%; the chances of a pregnancy are <4%. Greater complexity CCRs result in fewer transplantable embryos. Moreover, CCRs of greater complexity have a lower rate of high quality blastocysts than CCRs of less complexity.