Aneuploidy detection in single cells using DNA array-based comparative genomic hybridization. Mol Human Reprod 2004

The use of metaphase comparative genomic hybridization (CGH) to screen all human chromosomes for aneuploidy in preim-plantation embryos is hindered by the time required to perform the analysis. We report in this paper a novel approach to manu-facture a DNA microarray for CGH for the detection of aneuploidy in single cells. We spotted human chromosome-speci®c libraries on glass slides that were depleted of repetitive sequences and tested our array CGH method in 14 experiments using either single male and/or single female lymphocytes. For the autosomes, the mean normalized ratios were all close to the expected ratio of 1.0 with overall 300/308 (97%) of the normalized ratios falling within the range 0.75 to 1.25. It was possible to deduce the correct copy number of the X chromosome in 13/14 (92.9%) separate array CGH experiments but the Y chromosome in only 4/14 (29%). We tested our microarray CGH method on a single ®broblast from each of three cell lines containing a spe-ci®c chromosome aneuploidy (trisomy 13, 15 or 18) and in each case our microarray analysis was able to obtain a diagnosis based on the fact that the aneuploid chromosome gave the highest ratio (1.32, 1.27 and 1.27 respectively) with the ratios of all other chromosomes falling within the range 0.75±1.25. Requiring just 30 h, our method may be more suitable for PGD aneu-ploidy screening than metaphase CGH. Key words: aneuploidy screening/array CGH/microarray/preimplantation genetic diagnosis/single cell PC