Objective: To investigate influence of chromosomal translocations on early embryo development and to evaluate the efficacy and feasibility of preimplantation genetic diagnosis (PGD) techniques through clinical analysis on PGD cycles.
Methods: Embryo development, efficacy of PGD and clinical outcome of 100 cycles were studied retrospectively, including 23 cycles with Robertsonian translocations, 19 cycles with reciprocal translocations, and 58 cycles for α-Thalassaemia.
Results: Among 354 embryos biopsied by PGD for translocations, 321 (90.7%) presented fluorescence in situ hybridization (FISH) results. The rate of normal/balanced embryos in the Robertsonian translocation was 38.3% (64/167), which was significantly higher than 20.8% (32/154) in the reciprocal translocation group. Amplification was achieved in 443 blastomeres from 537 embryos in Thalassaemia group, which given to an amplification efficiency rate of 82.5% (443/537). Totally, 140 normal homozygous, 112 heterozygotes and 155 affected homozygous embryos were identified, while 36 embryos had uncertain result. The successful diagnostic rate was 75.8% (407/537). After 3 days in the translocation groups, the rate of normal and/or balanced translocations in biopsed embryos with ≥7 cells was 34.4% (77/224), which was significantly higher than 19.6% (19/97) of biopsed embryos with <7 cells. After 4 days, the compaction rate in normal/balanced embryos was 59.4% (57/96), which was significantly higher than 34.2% (77/225) in imbalanced embryos significantly. Seventy-five embryos transferred in 37 cycles with translocations group led to clinical pregnancy rate of 27.0% (10/37), and 170 embryos transferred in 58 cycles with Thalassaemia got a clinical pregnancy rate of 43.1% (25/58).
Conclusions: PGD can provide management efficiently for both chromosome translocations and Thalassaemia. Translocations might have slightly negative impact on embryo development before implantation.