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Objective: To achieve pregnancy with unaffected embryo using in vitro fertilization and embryo transfer (IVF-ET) and preimplantation genetic diagnosis(PGD) for the couples at risk of having children with beta-thalassemia., Methods: A couple carrying different thalassemia mutations of codon 41/42 and codon IVS2 position 654 received standard IVF treatment and intracytoplasmic sperm injection, embryo biopsy, single cell polymerase chain reaction and DNA analyses, and only the unaffected or carrier embryos were transferred to uterus. Pregnancy confirmation, and prenatal diagnosis were done at 20 week's gestation., Results: A total of 13 embryos were analyzed in the IVF cycle. PGD indicated that 2 were normal 18.1 , 3 were affected 27.3 , and 6 were carriers 54.5 ; diagnosis was not possible in 2. Three embryos were transferred to uterus on the third day after oocyte retrieval. Ultrasonography showed twin pregnancy with one blighted ovum. The prenatal diagnoses revealed that both fetuses were unaffected, one normal baby and one carrier were born., Conclusion: These studies represent the successful application of PGD for beta-thalassemia in China.

Objective: To achieve preimplantation genetic diagnosis (PGD) of the couples at risk of having children with beta-thalassemia, as an alternative to prenatal diagnosis., Methods: Two couples carrying different thalassemia mutations of codon 41/42 and codon intervening sequence 2 position 654 received standard in vitro fertilization treatment and intracytoplasmic sperm injection, embryo biopsy and the whole genome was amplified by primer extension preamplification (PEP). Nested polymerase chain reaction was then used to amplify two mutation sites separately. Both were detected by reverse dot-blot., Results: A total of 35 oocytes were retrieved from the two patients. Among them, 87% showed two pronuclei, and embryo biopsy was performed on 16 of these embryos and 25 blastomeres were obtained. The amplification efficacy was 84%. The genotype study of non-transferred and surplus embryos showed 15% of allele drop-out rate. Five embryos were transferred to the uterus of both patients. One pregnancy achieved, resulted in live healthy twin births, which confirmed the results of PGD., Conclusions: This unaffected pregnancy resulting from PGD by PEP for beta-thalassemia demonstrates that this technique can be a effective diagnostic tool for carrier couples who desire a healthy child.

Objective: To investigate the effect of in vitro fertilization and embryo transfer (IVF-ET) and preimplantation genetic diagnosis (PGD) for the couples at risk of having children with beta-thalassemia., Methods: Four couples carrying different thalassemia mutations received standard IVF treatment. Embryo biopsy was conducted. Single blastomeres were genotyped by a protocol involving primer extension preamplification, nested polymerase chain reaction and reverse dot-blot analysis. Only the unaffected embryos were transferred to the uterus., Results: A total of 97 oocytes were retrieved from the four female carriers. Among them, 83% showed two pronuclei. Embryo biopsy was performed on 47 of these embryos. The amplification efficiency was 84.8%. The average ADO rate was 14.9%. Ten unaffected embryos were transferred. A twin pregnancy with one blighted ovum was confirmed at 7 weeks' gestation by ultrasonography and one normal baby and one carrier of thalassemia mutation were born finally., Conclusion: This unaffected pregnancy resulting from PGD for beta-thalassemia demonstrates that PGD technique can be a powerful diagnostic tool for couples carrying beta-thalassemia mutations who desire a healthy child and wish to avoid abortion of an affected fetus.