Scientists Develop New Test to Detect Genetic Disorders in Embryos

by Rajashri on Oct 29 2008 2:34 PM

British researchers have developed a gene-mapping test that can tell parents-to-be if embryos are affected by almost any inherited disease.

The new technique called karyomapping, developed by a team from London's Bridge Centre can detect as many as 15,000 inherited diseases in weeks. It involved analyses of chromosomes.

For the test, a single-cell is taken from an eight-day-old embryo, created using IVF.

Then DNA samples are taken from the parents - and their parents.

Usually, another member of the family, most likely a child affected by the relevant condition, also provides a sample.

All those family members' DNA is then compared, looking at 300,000 specific DNA markers, allowing scientists create a map of the family's genetics.

The scientists determine 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.

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

"The current tests can only identify a small number of defects," BBC quoted Professor Alan Handyside, who has developed the test, as saying.

"One of the main things for patients is that, quite often, there isn't a test for their particular condition. This is a single test - a universal method," he added.

He said 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.

Trials are underway at the Bridge Centre.

"The effectiveness and efficiency of the procedure is quite exciting, and the fact it's quicker means it could be helpful to couples at risk of inherited diseases - and that in itself is significant," said Dr Mark Hamilton, chairman of the British Fertility Society.