Array Chromosomal Genome Hybridization (aCGH)- Based Preimplantation Geneticdiagnosis (PGD) for Balanced Translocation Carriers Improves both Diagnosticand Pregnancy Rates Compared to FISH and PCR Methods

Gheona Altarescu ¹ Sharon Zeligson ¹ Rachel Beeri ¹ David A. Zeevi ¹ Pinhas Renbaum ¹ Tali Mishael ² Yaffa Nevo ¹ Shira Shaviv Orit Lobel ¹ Rafi Ronel ³ Oshrat Schonberger ² Aharon Peretz ² Ehud J. Margalioth ² Ephrat Levy-Lahad ¹ Talia Eldar-Geva ²

¹Medical Genetics Institute, ZOHAR PGD Unit, Shaare Zedek Medical Center
²IVF Unit, 3Reproductive Endocrinology and Genetics Unit, Shaare Zedek Medical Center
³2IVF and Infertility unit, Assaf Harofeh Medical Center

Introduction: PGD for balanced translocations is usuallyperformed using FISH which analyzes only those chromosomes involved in thetranslocation. Single cell aCGH is a new technology which allows screening ofall chromosomes in addition to the chromosomal aberration.

Aims: To compare the efficiency of successful analysis andpregnancy rates for balanced translocations using three techniques: FISH, PCR,and aCGH.

Materials and Methods: Retrospective study of all PGD cases forbalanced translocations performed in the Shaare-Zedek PGD Unit since 2010. FISH(40 cycles) and PCR (14 cycles) analysis were performed on single cell biopsiesusing standard techniques. Single cell aCGH (12 cycles) was performed using theBlueGnome platform.

Results: Of 294 FISHanalyzed embryos, 210 were successfully diagnosed (71%) and 38 weretransferable in 22 cycles resulting in a pregnancy rate of 27% per transfer.Using PCR we analyzed 77 embryos; 53 were diagnosed (69%), while 21were transferable in 8 cycles, no pregnancy wasachieved. Using aCGH, 47 of 49 embryos were successfully diagnosed (96%).Twenty-oneembryos (45%) showed aneuploidies unrelated to the familial translocation. Nineembryos were transferable in 6 cycles leading to apregnancy rate of 67% per transfer. No significant differences in maternal age,number of oocytes retrieved or embryo quality was observed between the threegroups.

Conclusions: This preliminary data demonstrates that using CGHmicroarrays for PGD increases the efficiency of successful translocationanalysis. In addition, the CGH platform, which screens all chromosomes,significantly improves pregnancy rates. In light of these results, single cellaCGH for chromosomal aberrations should be used as the method of choice.