Northern Genetics Service

Array CGH

Array CGH (Comparative Genomic Hybridisation) is a technique for identifying sub-microscopic chromosome abnormalities. It is used for the diagnosis of dysmorphism, congenital abnormalities, mental retardation and developmental delay. Array CGH will identify copy number changes at a higher resolution than G-banding and will detect microdeletions and microduplications at known cytogenetic syndrome regions.


Referrals for array CGH are accepted on patients with possibly unbalanced karyotypes. Array CGH will not detect balanced rearrangements and has limited sensitivity for the detection of mosaicism. We strongly recommend that patients reported with a clinically significant copy number change are referred to our Clinical Genetics team for genetic counselling and any family follow-up studies.

Unfortunately, we are not able to accept samples for array CGH from patients who have previously had a normal G-banding karyotype analysis.  If you strongly suspect that these patients have a genetic abnormality, please refer them to a Clinical Geneticist for assessment.

Sample requirements and further details about the test are given here.

UNIQUE- The Rare Chromosome Disorder Support Group

Unique is a UK-based charity which provides a source of information and support to families and individuals affected by any rare chromosome disorder, and to the professionals who work with them. Found out more at the Unique website.

Among a wide range of leaflets produced in a range of languages, there are the following useful leaflets on Array CGH:


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