Preimplantation genetic diagnosis of chromosomal disorders: experience with 150 cycles conducted by a reference fertility clinic in Argentina

PERANDONES CLAUDIA; LAUDICINA ALEJANDRO; QUINTANS CARLOS; URQUIZA FERNANDA; RADRIZZANI MARTÍN; PASQUALINI SERGIO

Miami, Florida, USA

Conferencia; Nineth Conference in Preimplantation genetic diagnosis and Stem cells.; 2009

Preimplantation Genetic Diagnosis International Society

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 fluorescence in-situ hybridization in blastomeres from preimplantation human embryos. STUDY DESIGN: A short fluorescence in-situ hybridization procedure involving the simultaneous use of six deoxyribonucleic acid probes detected with red, green, blue, or a mixture of red-green and red-blue fluorochromes was developed to determine numeric abnormalities of chromosomes X, Y, 13, 18, 21 and 16. SETTING: A reference laboratory specializing in the provision of PGD services for chromosomal abnormalities. CYCLE(S): One hundred and fifty cycles were performed in patients at risk of transmitting chromosomal disorders to their children. INTERVENTION(S): In-vitro fertilization and PGD. MAIN OUTCOME MEASURE(S): Results of PGD cycles. RESULT(S): Successful analyses including biopsy, fixation, and fluorescence in-situ hybridization 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 first 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 8 are ongoing, with an additional 3 clinical miscarriages and 5 subclinical miscarriages (total miscarriage rate, including biochemical pregnancies, 16%). CONCLUSION(S): Preimplantation genetic diagnosis 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 Argentine for elective pregnancy termination of an affected fetus. Demand for this service at our center doubled in each of the last 4 years. Pregnancy rates per ET were encouraging, with almost half of all patients undergoing their first PGD cycle achieving a birth or ongoing pregnancy.