As the BBC has reported here, the first baby has been born in the UK whose birth was a function of preimplantation genetic diagnosis (PGD) for–or, rather, against–a gene, some of whose alleles have mutations strongly correlated with certain forms of breast and ovarian cancer. What follows are the basics, and two viewpoints on this, and a poll for you to participate in.
Basics: PGD is used in conjunction with in vitro fertilization when a number of eggs are fertilization, and so multiple embryos formed before any are implanted in the womb. This then allows for some testing on the embryos, and selection to be made amongst them in the light of the outcomes of the tests. One primary use of PGD is to screen for conditions seen as disabilities, when tests can be formed on embryos that are only a few days old; another is to test for sex, especially in countries where there is a decided preference for males (despite the use of those tests for this purpose being against the law there, e.g., China). BRCA1, touted early on (and misleadingly) as “the breast cancer gene”, was first detected in the early 1990s, and is known to play an important role in tumour suppression. Sometimes, it takes forms where it does not play this role. The BRCA1 gene is on chromosome 17 (band 21), and is associated with 5-10% of all breast cancers. In some forms that BRCA1 takes (alleles), the gene can reduce the risk of breast cancer developing in women who carry it; in other forms, it correlates strongly with mutations that give high risks of developing breast (and ovarian) cancer later in life. BRCA1 was the first gene associated with a risk for cancer that was approved for testing to be delivered in conjunction with PGD in the UK in 2006. All such approvals in the UK must be given by the Human Fertilisation and Embryo Authority; it has currently licensed PGD for about 60 genetic conditions.
First view: This is the view that you’ll find represented most prominently in the BBC article, and at H+biopolitics (which deserves a h/t here for posting on this: thanks!; there’s also some discussion at the Women’s Bioethics blog). This is a medical triumph that increases parental choice and lessens future suffering. It means that parents who have a history of susceptibility to a disease–at least 4 immediate female family members on the husband’s side in this case have developed the forms of cancer associated with BRCA1–can signficantly reduce the chances that children that they have will have children who go on to develop those cancers. Not all of those with the allele will develop those cancers, and there is some chance that the use of this testing in conjunction with PGD will lead to the discard of an embryo that would have a higher overall level of health, other things being equal. But medical intervention is never about certainty, only about improving the chances for health and reducing the chances of disease.
Second view: This is an objectionable use of genetic technology in itself that is also the thin end of the eugenic wedge. One might think that all combinations of PGD with genetic and other testing on embryos is morally objectionable, but put such views to one side here. Even if one thinks that some uses are justified (e.g. for cystic fibrosis), the decision to expand those uses to include cases like the BRCA1 gene–where the science has been hyped and the susceptibilities cannot be reliably estimated–is to both buy into a crass form of genetic determinism and to open the door to a massively expanded use of PGD that amounts to a dangerous form of eugenics. There are hundreds of correlations as strong and as questionable–as that between BRCA1 and breast and ovarian cancer. It is difficult to see how, once one of these becomes acceptable, that the others will follow suit. But that’s just negative eugenics all over again, now not on fetuses but on embryos.
The Wikipedia article on PGD provides very good coverage of PGD for those interested in following through; the article on the HFEA is sketchier but can be linked from the PGD article.