A single genetic test that is capable of detecting all mutations involved in the development of cystic fibrosis could be just a few years away, the 20th annual conference of the European Society of Human Reproduction and Embryology heard today (Monday 28 June).
Researchers at Monash University in Melbourne, Australia, have discovered that recently developed microarray (or “gene chip”) technology can be used successfully to detect one of the commonest cystic fibrosis (CF) genetic mutations with 100% accuracy.
This means that, once the technology has been refined, gene chips could be used to detect all CF mutations in a single, quick and easy test that would produce almost immediate results. The analysis could be carried out on embryos during preimplantation genetic diagnosis (PGD), so that only healthy embryos would be transferred to the woman. The technology could be used during PGD for other genetic diseases too.
Ms Chelsea Salvado, a PhD student working with Professor Alan Trounson and Dr David Cram at the Institute of Reproduction and Development at Monash, explained: “Currently there are many CF mutations diagnosed in the PGD laboratory, each requiring the development of a different diagnostic technique. However, the introduction of microarray technology would provide a uniform, single test, enabling PGD to be offered to couples presenting with different mutations without first having to undergo an extensive pre-clinical work-up. At present, this work-up can take anywhere between a week and six months to complete, depending on how easy it is to match the parental mutations with the markers used to prevent misdiagnosis.”
Until now, the possibilities of using microarray technology in PGD had been largely unexplored. Ms Salvado set out to discover the diagnostic potential of gene chips by testing them on the ∆F508 mutation, which is the commonest CF mutation, accounting for 80% of all CF mutations worldwide.
She created gene chips that held information on the normal and diseased versions of ∆F508 and then tested them on DNA samples obtained from single cells and from groups of ten cells. Despite some initial problems with amplifying the samples successfully, meaning that an extra step had to be added to the process, the final results showed that the gene chips could diagnose the ∆F508 mutation with 100% accuracy in the 30 samples investigated.