PGD and aneuploidy screening for 24 chromosomes by genome-wide SNP analysis: seeing the wood and the trees

Bisignano et al. (2011) argue that, for preimplantation genetic diagnosis (PGD) of aneuploidy for all 24 chromosomes, microarray-based comparative genomic hybridization (array CGH) is superior to the use of single-nucleotide polymorphism (SNP) genotyping arrays. Published studies indicate that both technologies accurately detect aneuploidy of whole chromosomes or chromosome segments. However, given the extra theoretical resolution and parent-of-origin information provided by SNP-based approaches, these may be particularly suited to certain applications such as PGD of single-gene defects or translocation chromosome imbalance combined with comprehensive detection of aneuploidy. A consensus on how to validate aneuploidy testing and all other clinically relevant information resulting from genome-wide analysis is needed urgently.