Molecular Tests Screens for Retinal Diseases

A custom resequencing chip has been designed to identify known and new mutations in retinal disease genes.

The retinal resequencing chip covers all exons of 90 retinal disease genes and it has been tested with multiplex primer sets for 1,445 amplicons representing the genes included on the chip.

A collaborative study carried out at the Netherlands Institute for Neuroscience (Amsterdam, The Netherlands), tested their retinal DNA resequencing chip and patient pooling strategy. This enabled detection of multiple retinal disease gene sequences in numerous patients, at the same time. DNA was extracted from peripheral blood from 60 patients with a variety of retinal disorders, including Leber's congenital amaurosis, ocular albinism, pseudoxanthoma elasticum, retinitis pigmentosa, and Stargardt's disease.

The custom 300-kb resequencing chip is designed for polymerase chain reaction (PCR) amplification, DNA fragmentation, and chip hybridization performance. Hybridization signals were analyzed using appropriate detection software and this resequencing approach was validated by Sanger sequence technology. The new chip can screen up to 90 retinal disease genes in as many as 20 patients at the same time and return results faster than current tests. Since 150 genes related to 30 retinal diseases have been identified, and on average, at least five genes must be considered for each type of disease.

Arthur A.B. Bergen, PhD, the lead author of the study, said, "In initial and replicated tests, we achieved a high 99% detection rates, 100% reproducibility of results and no false-positives. Unlike current methods, our chip can detect both known and new genetic sequence changes associated with retinal disorders, an advance that will further our understanding of disease mechanisms as well as improving diagnosis and treatment. The chip is fully validated for DNA diagnostic purposes, and an upgraded version will be available in early 2011 at the Netherlands Institute for Neuroscience, Amsterdam. The study was published in January 2011, in the journal Ophthalmology.

Related Links:
Netherlands Institute for Neuroscience