About Health – Universal embryo test ‘very near’
About Health –
The test should tell if an embryo is healthy
A gene mapping test that can test embryos for almost any inherited disease could be available in the UK within a year, say researchers.
Unlike current tests doctors do not need to know the specific gene mutation involved.
At the same time embryos can be tested to check they are generally in good genetic shape.
Experts say there will have to be strict limits on what the test can be used for.
We’re not mad Frankenstein’s working away in our laboratories to create designer babies
Professor Tony Rutherford
British Fertility Society
The test – which will cost around £2,500 – uses a technique called karyomapping which looks for the inheritance of sections of DNA or chromosomes.
Rather than knowing the exact gene mutation which is passed down the generations in an family affected by a condition such as cystic fibrosis, doctors can just look for the block of DNA containing a faulty gene.
At the moment genetic testing of embryos is generally limited to a few conditions.
But karyomapping could in theory be used to test for any one of the 15,000 genetic defects known about.
Using the same test doctors could also look at whether any chromosomes are missing or duplicated which suggests the embryo will not be viable.
It would also be far quicker than current tests, taking only three days instead of weeks or months.
Professor Alan Handyside, from London’s Bridge Centre, who developed the test said in the handful of families they had looked at, it had been 100% successful in picking up affected embryos.
US researchers have also run the test in embryos at risk of cystic fibrosis.
In five cases where families had donated embryos to research, they proved the test can pick up cystic fibrosis mutations.
At the same time they found serious chromosome abnormalities suggesting those embryos would not have resulted in successful pregnancy, delegates at the European Society of Human Reproduction and Embryology conference heard.
That could boost the chance of a couple having a successful pregnancy through IVF as well as a baby free from the condition in question.
The UK team has applied to the Human Fertility and Embryology Authority (HFEA) for a licence.
Clinical trials of the test are due to start by the end of the year.
Regulators will be assessing whether it works and whether it is safe.
But there are also ethical issues to consider.
Ultimately, the test could be used to test for conditions which are not serious or life-threatening – leading to concerns about designer babies.
The HFEA will be able to set conditions on what the test can be used for.
Professor Handyside said one use for the test could be looking for genetic causes of autism which occurs in 5% of cases.
Other likely candidates are Huntington’s disease and spinal muscular atrophy – a condition that can cause death in infancy.
"What we’re mapping is inheritance from the father and the mother across the entire genome.
"The potential criticism of this work is we could find all kinds of changes in the embryo.
"But we wouldn’t get a licence to do this for all conditions.
He added: "We are limited in the number of embryos we can test so something has to be very likely to turn up."
Professor Tony Ruthford, chair of the British Fertility Society said the test would be more reliable although admitted such technology was opening a "Pandora’s box".
"The issue here is we may find out a lot of genetic information and how is that going to be used or stored."
But he said the regulations in the UK on what could be tested for were very strict and would remain so.
"We’re not mad Frankenstein’s working away in our laboratories to create designer babies.
"We are only allowed to look for major diseases which cause handicaps."