S-16 Reproductive BioMedicine Online, Vol. 18, Suppl. 3, May 2009 Abstracts – PGDIS: 9th International Symposium on Preimplantation Genetics PGD for an intrachromosomal insertion 7 in a male and a female balanced carrier Xanthopoulou L, Mantzouratou A, Ranieri DM, Delhanty J Introduction: Two related family members, a female and a male balanced carrier of a direct between-arm intrachromosomal insertion on chromosome 7 were referred to our centre for PGD. Different segregation patterns at meiosis could result in embryos balanced or unbalanced due to the duplication or deletion of the inserted segment, with the risk of an unbalanced offspring being up to 50%. Materials and methods: Two PGD cycles for the female carrier (22 embryos biopsied) and three PGD cycles for the male carrier (19 embryos biopsied) are described here. In general, two blastomeres were biopsied per embryo and analysed by FISH using the William’s dual-band probe, which hybridizes at two loci on chromosome 7: a control site (7q11.23) and a site included within the insertion segment (7q31). Follow- up analysis of 29 untransferred embryos on day 5/6 was also performed. Results: From the 22 embryos of the female carrier, 11 were balanced, fve had duplication and two had deletion of the inserted segment, two had monosomy 7, one was balanced/ unbalanced mosaic and one had an inconclusive result. A pregnancy and the birth of a healthy girl was achieved after the frst PGD cycle. After the second cycle, a pregnancy was established but was ectopic. On follow-up there were four chaotic embryos, two unbalanced, one balanced, two unbalanced/chaotic mosaics, two balanced/chaotic mosaics and two embryos with inconclusive results, whereas the meiotic segregation patterns included fve with balanced segregation, four with duplication and one with deletion of the inserted segment and three with unknown segregation. For the male carrier, out of the 19 embryos, six were balanced, fve had deletion and two had duplication of the inserted segment, two had monosomy 7, whereas four had inconclusive results. For the male carrier, no pregnancies were established from the frst two PGD cycles (no embryo transfer after the third cycle). On follow-up there were nine chaotic embryos, one unbalanced/ chaotic mosaic, one balanced/chaotic mosaic, two unbalanced and three with inconclusive results. The meiotic segregation patterns on day 5/6 included fve embryos with duplication and four with deletion of the inserted segment, six with unknown segregation and one with balanced segregation. Discussion: In the preimplantation stages of development, it is possible to see all the different segregation patterns of the insertion chromosome, which might not be viable in later stages of development. Although post-natal studies report no difference in fertility between male and female insertion carriers, in this study the female carrier produced far more balanced embryos than the male (50% and 31.5% respectively) and also achieved pregnancies. On follow-up, the male carrier had produced more chaotic embryos than the female (56% and 31% respectively). In the female carrier, the most common segregation pattern on day 5/6 was balanced segregation, whereas in the male it was the duplication of the inserted segment. This is one of the few studies to show how an insertion would behave in the preimplantation stages of development in a male and female carrier. Conclusion: These results demonstrated that, remarkably, even embryos with higher grading on both day-3 and day-4 assessments, approximately 50% of embryos were diagnosed as chromosomally abnormal, which demonstrates a higher discrepancy between embryo morphology/grading and PGD results. Chromosomally normal and abnormal embryos cannot exactly be distinguished morphologically on day 3. It means that the morphology of an embryo on day 3 is not predictive about the normality of the chromosomes. The developmental ability of normal embryos is higher than abnormal embryos until day 4 according to our results. On the other hand, despite their low frequency on day-3 grade I/II embryos, developmental competency of monosomic and mainly trisomic embryos is as high as normal embryos. PGD of chromosomal disorders: experience with 150 cycles conducted by a reference fertility clinic in Argentina Perandones C, Laudicina A, Paganini A, Quintans C, Donaldson M, Urquiza F, Radrizzani M, Pasqualini S Halitus Instituto Médico, MT de Alvear 2084 Cap. Fed, Laboratorio de Neuro y Citogenética Molecular, Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín: e-mail: cperandones@leloir.org.ar; claudia.perandones@ gmail.com Objective: Our purpose was to determine the feasibility of ascertaining aneuploidy for chromosomes X, Y, 18, 13, 21 and 16 by use of multiple-probe FISH in blastomeres from preimplantation human embryos. Materials and methods: A short FISH procedure involving the simultaneous use of six deoxyribonucleic acid probes detected with red, green, blue, or a mixture of red–green and red–blue fuorochromes was developed to determine numeric abnormalities of chromosomes X, Y, 13, 18, 21 and 16. In a reference laboratory specializing in the provision of PGD services for chromosomal abnormalities, 150 cycles were performed in patients at risk of transmitting chromosomal disorders to their children undergoing IVF and PGD and outcomes of PGD cycles were recorded. Results: Successful analyses including biopsy, fxation and FISH were achieved in 91% of the blastomeres. Of the six chromosomes tested, numeric aberrations were found in 37% of developing embryos, including aneuploidy, polyploidy, haploidy, and mosaicism. There was a tendency for aneuploidy to increase with maternal age. 70% of patients undergoing PGD had at least one euploid embryo for transfer in the frst cycle. 64% of this group of patients also had at least one euploid embryo available for transfer in the second cycle. The global pregnancy rate was about 30%. To date, 32 pregnancies have been delivered and eight are ongoing, with an additional three clinical miscarriages and fve subclinical miscarriages (total miscarriage rate, including biochemical pregnancies, 16%). Conclusion: PGD offers infertile couples the earliest form of genetic screening and may help improve ongoing pregnancy rates in poor-prognosis patients. Also, PGD for chromosomal disorders has been shown to be an effective alternative to prenatal diagnosis for patients with an ethical or a religious objection to pregnancy termination and in the present restrictive legal context in Argentina for elective pregnancy termination of an affected fetus. Demand for this service at our centre has doubled in each of the last 4 years. Pregnancy rates per embryo transfer were encouraging, with almost half of all patients undergoing their frst PGD cycle achieving a birth or ongoing pregnancy.