Gender determination and detection of aneuploidy in single cells using DNA array-based comparative genomic hybridization

Comparative Genomic Hybridization (CGH) using metaphase chromosome spreads to screen all human chromosomes for aneuploidy in preimplantation embryos is hindered by the time required to perform the analysis. DNA microarrays manufactured to date are not able to analyze the very limited amount of genetic material in a single cell. We have developed a DNA Microarray-Comparative Genomic Hybrydization (CGH) approach, which is capable of screening all 24 human chromosomes for aneuploidy and sex chromosomal abnormalities in a single cell. This technique has a number of applications including aneuploidy detection in single fetal cells isolated noninvasively from pregnant women for prenatal diagnosis. In this chapter, we describe in detail the methodology of this technique, including preparation of a single cell sample, whole genome amplification of single cells, microarray CGH hybridization (array CGH), data analysis of array CGH, and the diagnostic criteria of aneuploidy detection. We anticipate that with further automation of part of this technique it will become a high-throughput diagnostic tool.