The clinical application of whole chromosome painting probes in preimplantation genetic diagnosis for translocation carriers / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To make preimplantation genetic diagnosis (PGD) for female translocation carriers by analyzing first polar bodies (1PBs) with whole chromosome painting probe (WCP).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>WCP can differentiate normal, balanced and unbalanced oocytes accurately and can be used as an efficient PGD method for female carriers of translocation.</p>

Analysis of chromosome mosaicism in preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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 <or= 4 cell stage to 40.0% in 5-8 cell stage embryos. The aneuploidy rate for the patients over 35 years of age was significantly higher than that of the patients under 35 years (57.1% vs 23.3%).</p><p><b>CONCLUSION</b>Mosaicism is common in human preimplantaion embryos, which may be one of the important factors affecting the success rates in IVF-ET. Most of the chromosomal abnormalities can be identified by two sequential rounds of FISH.</p>

Sperm sex chromosome analysis and preimplantation genetic diagnosis of patients with sex chromosome anomalies / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the constitution of abnormal spermatozoa from patients with sex chromosome anomalies.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>