London, Jul 8 (PTI): A healthy boy in the US has become the world's first test tube baby to be born using a new low cost "next-generation sequencing" IVF technique that screens the embryo for genetic defects, Oxford scientists announced today.
The method, through which the baby was born last month, uses the latest DNA sequencing techniques and aims to increase in-vitro fertilisation success rates while being more affordable for couples and lowering the risk of miscarriages, researchers say.
The international team led by Dr Dagan Wells of Oxford University showed how "next-generation sequencing" can be used to pick the embryos created by IVF that are most likely to lead to successful pregnancies.
The approach can identify embryos with the correct number of chromosomes and may cut hundreds of pounds off the cost of embryo screening, Wells said.
The majority of embryos produced by IVF aren't able to lead to successful pregnancies, and scientists have sought to find ways of identifying the embryos that should be implanted to give the greatest chance of success.
Having an incorrect number of chromosomes usually prevents embryos from producing a pregnancy. Until recently, such abnormalities have been hard to detect as they do not affect the appearance of embryos under the microscope.
"Many of the embryos produced during infertility treatments have no chance of becoming a baby because they carry lethal genetic abnormalities," Wells, said. "Next-generation sequencing improves our ability to detect these abnormalities and helps us identify the embryos with the best chances of producing a viable pregnancy. Potentially, this should lead to improved IVF success rates and a lower risk of miscarriage," he said.
Recently, a number of trials of various chromosome screening methods have shown that they can improve IVF success rates by around 30 per cent. But the costs of these genetic tests remain a barrier to their widespread use.
This led Wells and colleagues to look at the possibilities of using the latest in DNA sequencing technology to screen embryos for chromosomal abnormalities.
"Results from randomised clinical trials carried out during the last year have suggested that most IVF patients would benefit from embryo chromosome screening. However, the costs of these genetic tests are relatively high, putting them beyond the reach of many patients. Next-generation sequencing could make chromosome testing more widely available, improving access by cutting the costs," Wells said.
The researchers' approach involves sequencing DNA from multiple embryos all at the same time. Short DNA tags or 'barcodes' added to the genetic material from each individual embryo mean that the results could be identified uniquely and mapped back to the right embryo.In the future, it should be possible to use the approach to check for chromosomal abnormalities and any serious inherited disorders at the same time, researchers said.