There is no interchromosomal effect in the embryos derived from young carriers of reciprocal and robertsonian translocations

Abstract

This study aimed to analyse ICE in human preimplantation embryos derived from both reciprocal and Robertsonian translocation carriers who were undergoing preimplantation genetic diagnosis (PGD). Eleven cycles of PGD for Robertsonian translocation and twelve cycles of PGD for reciprocal translocation outcomes were analysed retrospectively from August 2010 to February 2011 in Bahceci Assisted Reproductive Technology Centres. PGD was performed for 200 cleavage stage embryos derived from translocation carriers in younger women (average maternal age of 33 for reciprocal and 30 for Robertsonian translocation carriers) using multicolour fluorescent in situ hybridisation (FISH). An additional aneuploidy screening was performed by multicolour FISH for nine chromosomes (13, 15, 16, 17, 18, 21, 22, X and Y). A further 214 cleavage stage embryos (average maternal age of 32) with no structural chromosomal abnormalities were analysed as a control group. PGD was performed for 86 cleavage stage embryos derived from 10 couples carrying Robertsonian translocations and 11 couples carrying reciprocal translocations. This study showed that the female carriers of both Robertsonian and reciprocal translocations have a similar chance of producing a balanced embryo with normal copy number of the seven chromosomes analysed (13, 15, 16, 17, 18, 21, 22, X and Y). The risk of having an aneuploidy in one of these nine chromosomes was higher in embryos carrying either Robertsonian and reciprocal translocations. This study shows that there is ICE in the unbalanced embryos derived from carriers of both reciprocal and Robertsonian translocation.