[Efficiency comparison between two preimplantation genetic diagnostic methods for chromosomal translocation carriers].

OBJECTIVE: To compare the diagnostic efficiency between blastomere preimplantation genetic diagnosis (PGD) and polar body PGD for chromosomal translocation carriers. METHODS: Group A had 8 cycles using whole painting probes for the first polar body diagnosis, while group B had 29 cycles using two subtelomeric probes and one centromeric probe for the blastomere diagnosis. RESULTS: The fertilization rate of group A was significantly lower than group B [66.1% (72/109) vs 85.2% (304/357), P < 0.05]. There was no significant difference in the successful biopsy rate between two groups. However, group A had a significantly higher loss rate during fixation and higher no signal rate after fluorescence in situ hybridization [FISH, 9.6% (12/104) vs 1.6% (4/252), 11.2% (10/89) vs 3.0% (7/233)]. Totally, the diagnostic efficiency in group A (72.5%, 79/109) was significantly lower than that in group B (89.8%, 230/256, P < 0.05). Although both the clinical pregnancy rate (3/7) and implantation rate (22.2%, 4/18) of group A were higher, the differences were not statistically significant (P > 0.05). CONCLUSION: Both methods can be used efficiently in the PGD for chromosomal translocation carriers. Blastomere PGD has a higher diagnostic rate.

[Analysis of chromosome mosaicism in preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization].

OBJECTIVE: To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH). METHODS: Totally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Y were analyzed. RESULTS: Among 51 embryos, 16 (31.4%) were mosaic, 12 (23.5%) were chaotic, and the remaining were either normal (27.5%) or non-mosaic abnormal (17.6%). The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from 12.5% in embryos

[The clinical application of whole chromosome painting probes in preimplantation genetic diagnosis for translocation carriers].

OBJECTIVE: To make preimplantation genetic diagnosis (PGD) for female translocation carriers by analyzing first polar bodies (1PBs) with whole chromosome painting probe (WCP). METHODS: WCP was used in fluorescence in situ hybridization (FISH) analysis of 1PBs for four female Robertsonian carriers presented for PGD with 45 XX, der(13;14)(q10;q10) karyotype. All the patients underwent ovarian stimulation and during 6 h after oocyte retrieval 1PBs were biopsied and WCP were used in FISH. On day 3 after fertilization embryos diagnosed as normal or balanced were transferred. RESULTS: A total of 61 oocytes were collected in 4 PGD cycles. Of the 54 matured oocytes, 50 were biopsied and 45 were fixed successfully. Results were obtained in 40 1PBs. Overall, 74.1% (40/54) oocytes were diagnosed. The fertilization rate and good embryo rate were 64.8% (35/54) and 65.7% (23/35) respectively. Two clinical pregnancies were obtained. One patient delivered a normal female baby with karyotype 46, XX in June 2006. For another patient, the fetus spontaneously aborted at 9th week of pregnancy with karyotype of 45, X confirmed by amniotic villus diagnosis. CONCLUSION: WCP can differentiate normal, balanced and unbalanced oocytes accurately and can be used as an efficient PGD method for female carriers of translocation.

[Sperm sex chromosome analysis and preimplantation genetic diagnosis of patients with sex chromosome anomalies].

OBJECTIVE: To investigate the constitution of abnormal spermatozoa from patients with sex chromosome anomalies. METHODS: Triple color fluorescence in situ hybridization (FISH) was used to determine the sex chromosome constitution of spermatozoa from three patients with sex chromosome anomalies (case 1:46,XY/47,XXY, case 2:45,XO/46,X,Yqh-, case 3:47,XXY). The preimplantation genetic diagnosis (PGD) was performed to case 2. RESULTS: An increased ratio (2.05 vs 1) of X-bearing to Y-bearing spermatozoa was only observed in case 2, who also had an increased incidence of total abnormal spermatozoa (29.71%). An increased incidence of total abnormal spermatozoa (4.91%) was also observed in case 3. Among the constitution of abnormal spermatozoa, case 2 had the increased proportions of XY18 disomy, O18 monosomy and XO monosomy, while case 3 had an increase proportion of XY18 disomy (1.87%). PGD was performed to case 2 and one embryo with XX1818 was selected for implanting. CONCLUSION: Using FISH to detect the sperm sex chromosomes in patients with sex chromosome anomalies can provide the useful information to evaluate the risk of sex chromosome anomalies in preimplantation embryos.