13 July 2007
Three European research institutes (the University of Nijmegen in the Netherlands, the University of Tuebingen in Germany, and the NHS Regional Genetics Laboratory in Birmingham, UK) are joining with commercial company Affymetrix to form the European Cytogenetic Research Initiative. This is a collaborative project to use microarrays (also known as DNA chips) to study chromosomal abnormalities linked to mental retardation in children.By examining genetic material at higher resolution than is possible using conventional cytogenetic analyses, the researchers expect to identify more abnormalities; currently, it is not possible to identify the cause of learning disability in children in a large proportion of cases, but making a diagnosis can be of great value to families, including for improved clinical management.
Olaf Riess of the University of Tuebingen commented: "With this technology, we expect to find a much higher number of causal de novo deletions and amplifications than we could with the current gold-standard methods like karyotyping" (see press release). However, the difficulty may lie not so much in identifying chromosomal mutations and rearrangements as with establishing a definitive causal link between a given abnormality and the observed clinical phenotype of the child.
The use of array-based technology for the diagnosis of learning disability has recently been explored by a UK Genetic Testing Network (UKGTN) working party; the report, Evaluation of array-CGH for chromosomal abnormalities in clinical practice, is available from the PHG Foundation website.