Single nucleotide polymorphism microarray-based concurrent screening of 24-chromosome aneuploidy and unbalanced translocations in preimplantation human embryos

Objective: To develop, validate, and apply a single nucleotide polymorphism (SNP) microarray-based method for simultaneous preimplantation genetic diagnosis (PGD) of unbalanced inheritance of rearranged chromosomes and 24-chromosome aneuploidy screening.

Design: Prospective clinical research study.

Setting: Academic reproductive medicine center.

Patient(s): Eighteen couples carrying a balanced reciprocal or Robertsonian chromosomal rearrangement.

Intervention(s): PGD on blastocyst trophectoderm biopsy specimens.

Main outcome measure(s): Aneuploidy, implantation, pregnancy, and delivery rates after SNP microarray-based aneuploidy and translocation screening.

Result(s): Single nucleotide polymorphism microarray was capable of detecting translocation-associated imbalances as small as 9.0 megabases. In the 12 transfers performed, sustained implantation occurred for 9 (45%) of 20 balanced-normal and euploid embryos replaced. The clinical pregnancy rate in patients receiving a transfer was 75% with six singleton deliveries and three ongoing singleton pregnancies thus far. Significantly fewer embryos were eligible for transfer with the incorporation of simultaneous 24-chromosome aneuploidy screening. Arrested embryos were also significantly more likely to possess unbalanced chromosomes when compared with developmentally competent blastocysts.

Conclusion(s): This SNP microarray-based method provides the first opportunity to improve outcomes through comprehensive identification of euploid embryos from translocation carrier couples.