Now clinics can be aware of the X-linked diseases and can take precautionary measures to discard the affected embryos. This leads to wastage of fewer embryos. Professor Peter Braude of King's College London, who was involved in the research, says that this technique can cherry pick healthy embryos for women at risk of passing on inherited diseases. The most common disease that goes unnoticed or is very difficult to detect in the early stage are DMD and Cystic Fibrosis. Statistics show that about 100 boys are born with DMD in Britain daily whose average life expectancy is 17 years. The research is to be presented at the annual meeting in Prague of the European Society of Human Reproduction and Embryology.
The technique is called preimplantation genetic haplotyping. It was first done by Ali al-Hellani, a Saudi Arabian fertility specialist. But it was modified later Pamela Renwick at Guy's hospital genetics centre and Prof Braude, who runs a fertility centre at Kings College, London. The test basically relies on the extraction of one of eight cells from a three-day-old embryo. Then the DNA is extracted from the cell which undergoes the process of multiple displacement amplification to replicate the DNA. Then they blood samples from family members, including at least one person affected by the disease is collected and the DNAs are compared. It is possible to identify the region of a chromosome that is responsible for the disease. The treatment costs Ģ4,100. The Guy's team has applied for licences to test for other genetic diseases, such as fragile X- syndrome and myotonic dystrophy. Stuart Lavery, a fertility expert at Hammersmith hospital, London, said the research would give many couples the first chance of having healthy children.