The recent non-invasive sequencing of an unborn baby's genome, using cell-free fetal DNA in the mother's bloodstream, found a range of mutations in the child's genome that were not seen in either of the parents. During pregnancy, up to 10% of the cell-free DNA in a woman's bloodstream comes from the fetus.
This technology could lead to safer non-invasive tests to find genetic biomarkers for severe inherited and congenital genetic disorders, which previously could only be detected after birth or through invasive tests taking amniotic fluid or tissue samples. However, it has raised a lot of ethical issues, too, with a mixed and emotional response across the blogosphere.
This screen can detect changes as small as alterations in individual letters in the genetic code. While these, known as single nucleotide polymorphisms (SNPs), can lead to genetic disorders, many are in the non-coding region and have little significance. Many changes in the genome, including SNPs and other changes, simply change the tendency toward a disorder such as schizophrenia, rather than definitively state that the child will have that outcome.
There are concerns that spotting these genetic markers could increase the number of abortions of fetuses that would otherwise be perfectly healthy, or even not go on to develop the disease, and that it would lead to increased stigma for children who do have these diseases and still lead normal lives. However, there is a flip side--finding out about a potential disorder could allow parents to be prepared for the birth of a child with additional needs, or mean that healthcare professionals could monitor some children from birth and treat conditions earlier, improving their outcomes. Like many scientific step-changes, this brings great potential with ethical dilemmas, and we need to be aware of the ethics as well as the scientific amazement. -- Suzanne Elvidge (email)