Comparative Genomic Hybridisation (CGH)

Children with learning difficulties and birth defects are often referred for assessment by clinical geneticists to see if their health problems are caused by a change in their chromosome pattern. Standard chromosome tests do not identify small changes, leaving some families with uncertainty about the cause of their child’s health problems and the recurrence risks. Array CGH (aCGH) is a technique which identifies small chromosome changes resulting in significant learning and developmental problems.

Nowgen undertook a health economic modeling evaluation of the impact of introducing this test into clinical practice in the NHS.

DNA samples are taken from individuals with learning difficulties and birth defects, and treated with a colour dye. This is then attached to a microarray slide (a glass slide with known DNA fragments on it). The slide can then be read automatically by a scanner and the pattern compared to that of a sample from a healthy individual. This analysis can identify areas of missing or extra DNA that cannot be seen under the microscope.

The Regional Cytogenetics Laboratory in Manchester has developed aCGH. This technique complements the Clinical Genetics Service, with its international reputation for the diagnosis and clinical management of children with learning difficulties and birth defects.

At present aCGH is expensive. Nowgen undertook a health economic modeling evaluation of the impact of introducing this test into clinical practice.

Investigators

Bill Newman, Linda Davies, Jill Clayton Smith

Funding Body

Department of Health

Publications

Newman WG, Hamilton S, Ayres J, Sanghera N, Smith A, Gaunt L, Davies LM, Clayton-Smith J. Array comparative genomic hybridization for diagnosis of developmental delay: an exploratory cost-consequences analysis. Clinical Genetics. 2007 Mar;71(3):254-9.