Use of single nucleotide polymorphism microarrays to distinguish between balanced and normal chromosomes in embryos from a translocation carrier

Objective: To prove the ability to distinguish between balanced and normal chromosomes in embryos from a translocation carrier. Design: Case report. Setting: Academic center for reproductive medicine. Patient: A female with a balanced translocation causing Alagille Syndrome seeking preimplantation genetic diagnosis (PGD). Interventions: Blastocyst biopsy for PGD. Main outcome measures: Consistency of 3 methods of embryo genetic analysis (real-time PCR, SNP microarray, and FISH) and normalcy in the newborn derived from PGD. Results: PGD was applied to 48 embryos. Real-time PCR, SNP microarray, and FISH demonstrated 100% consistency, although FISH failed to detect aneuploidies observed by comprehensive SNP microarray based analyses. Two blastocysts were identified to be normal for all 3 factors using SNP microarray technology alone. The two normal embryos were transferred back to the patient resulting in the delivery of a healthy baby boy with a normal karyotype. Conclusions: This is the first report of validation and successful clinical application of microarray based PGD to distinguish between balanced and normal chromosomes in embryos from a translocation carrier. Affymetrix SNP arrays were processed according to the manufacturer's directions on DNA extracted from 17 blastocysts on biopsied trophectoderm samples and 31 arrested whole embryos. Afflymetrix SNP array analysis was successfully completed on 17 trophectoderm, 30 whole embryo and 3 gDNA samples.