A new way of sparing couples the trauma of having to decide between having a baby with a high risk of developing a form of colorectal cancer later in life, or terminating the pregnancy, will be revealed on Tuesday, 20 June 2006 at the 22nd annual conference of the European Society of Human Reproduction and Embryology in Prague, Czech Republic.
Professor Stéphane Viville, director of the biology of reproduction service at Strasbourg University Hospital, Strasbourg, France, will tell the conference that, using his team's new test, it will be possible to offer preimplantation genetic diagnosis (PGD) to almost all cases of familial adenomatous polyposis (FAP), an adult-onset cancer which represents 1% of all cases of colorectal cancer.
PGD was originally proposed for couples at risk of having a child affected by severe genetic disorders such as cystic fibrosis, which manifest themselves at birth or in very early childhood. However, it is now possible to test for some diseases that occur at a later stage in life, such as Huntington's disease and some hereditary cancers. "Because the child will carry only a risk - albeit it a high one - of developing these conditions during adulthood, many parents, as well as clinicians, have doubts about terminating such a pregnancy," Professor Viville says. "In fact some couples would prefer not to have children in these circumstances."
Twelve couples with a risk of passing on FAP to any children were referred to Professor Viville and his team between 2000 and 2005. At first the team worked on tests to detect the most common FAP mutation, but then, by carrying out double and triple diagnostic tests on each cell, were able to detect the many rarer mutations that are involved in familial cases. "Because the pathology is dominant, and only one member of the couple is affected and at risk of transmitting the disease," said Professor Viville, "we only have to look for one mutation at a time.