CGHarray

CGH array, also known as comparative genomic hybridization array, is a molecular cytogenetic technique used to detect and quantify copy number variations (CNVs) in the genome. CNVs are alterations in the DNA that result in either the duplication or deletion of segments of genetic material. These variations can range from a few kilobases to megabases in size and can have significant implications for health, being associated with various genetic disorders, developmental abnormalities, and even cancer.

The principle behind CGH array involves hybridizing two different samples of DNA to a microarray containing thousands of DNA probes. One sample is typically from a reference genome with a known normal copy number, while the other is from the sample being tested, often from a patient. Both DNA samples are labeled with different fluorescent dyes. The labeled DNA samples are then mixed and applied to the array. If a particular genomic region is duplicated in the test sample compared to the reference, the test DNA will bind more strongly to the corresponding probe on the array, resulting in a stronger fluorescent signal from the test dye. Conversely, if a region is deleted in the test sample, the reference DNA will bind more strongly, leading to a stronger signal from the reference dye.

By analyzing the relative fluorescence intensities across the array, researchers and clinicians can identify specific chromosomal regions that are amplified or deleted in the test genome. CGH arrays offer a higher resolution than traditional karyotyping for detecting CNVs and have become a crucial tool in diagnostics for a wide range of genetic conditions, including intellectual disability, congenital anomalies, and certain types of cancer, aiding in diagnosis, prognosis, and personalized treatment strategies.