What is array comparative genomic hybridisation (aCGH)?

Array Comparative Genomic Hybridisation (aCGH) is a microarray-based technique to detect alterations in Genomic DNA sequence.

Array CGH is widely used for clinical research into constitutional cytogenetics, rare disease, cancer and reproductive health.

The technique involves labelling a test (patient) DNA sample and a reference (control) DNA sample  with Cyanine 3 and Cyanine 5, green and red fluorescent dyes, respectively. After labelling the test and reference DNA samples are mixed together and loaded onto a microarray comprised of tens of thousands of short DNA sequences representing regions of the genome. The pooled samples will competitively hybridise to the DNA probes on the array.

Dual colour fluorescence detection is used to detect the relative signal intensity of both dyes, highlighting differences, if any, in copy number between the samples.

aCGH offers high resolution, genome wide analysis for detecting whole chromosome aneuploidies, sub microscopic deletions and duplications down to single exon resolution and copy neutral events such as Loss of Heterozygosity (LoH) and uniparental disomy (UPD).