Universal test for genetic diseases in unborn children in the pipeline

Oct 27 2008

A team of British scientists have developed a ground-breaking new test to screen for genetic diseases in unborn children.

The test, developed at the Bridge Centre in London, could be used to screen for many devastating syndromes, diseases and conditions and could prevent any genetic disease in unborn children.

Professor Alan Handyside who developed the test says it will allow all prospective parents the choice of continuing with the artificial insemination, will cost around £1,500 and could be available as early as next year.

The test will not only alter the range of innate disorders, but will also increase the speed and accuracy of existing tests and could also improve the probability of pregnancy for those who are infertile by selecting embryos which have the best chance of developing normally.

The test entails the use of a technique known as karyomapping, which analyses chromosomes, it is a universal 'one size fits all' test, in which a cell is taken from an embryo which is just a few days old created using IVF.

DNA samples are then taken from the parents - and their parents and another member of the family, most likely a child affected by the relevant condition, the family members' DNA is then compared, looking at 300,000 specific DNA markers, which allows scientists to create a map of the family's genetics.

This means they can, for example, identify if there is a block of DNA which has been passed on by the paternal grandfather to an affected child and if it is also present in the embryo - because the markers will be the same for all three.

For example, the gene for cystic fibrosis lies on chromosome 7 and if the paternal grandfather was a carrier, and the embryo has inherited a section of DNA at that particular position, the embryo will have the faulty gene.

The same check can be carried out across all chromosomes to allow screening for multiple genes and the researchers say the test could detect any of the 15,000 inherited diseases in weeks - current tests are either focused on a specific gene mutation, or take a lot longer to give results.

Professor Alan Handyside says the test could also be used, more controversially, to detect a genetic profile which showed a susceptibility to conditions such as heart disease or cancer.

Once Professor Handyside has enough data he says he will apply to the fertility regulator, the Human Fertility and Embryology Authority, for a licence to use the test - an HFEA spokeswoman said its licensing committee would be able to set conditions on what it could be used for.

Fertility experts say while the effectiveness and efficiency of the procedure is exciting, the ethical question remains, "if you can screen for anything, where do you draw the line?"