GENETIC SCREENING: HOPES AND CAUTIONS

The BBC reported on the birth of the first baby in the UK tested before conception for a genetic form of breast cancer: “The embryo was screened for the altered BRCA1 gene, which would have meant the girl had an 80% chance of developing breast cancer,” as “women in three generations of the husband’s family have been diagnosed with the disease in their 20s.”

The process involves the testing of a cell taken from the embryo when it is about 3 days old, before “conception” – when the embryo is implanted in the womb. Any embryos that show a genetic profile that might cause future problems are discarded. A mutated BRCA1 gene could potentially give an increased chance of breast cancer and a 50% chance of ovarian cancer later in life, although neither would have been inevitable.

Although well-established, this process, called Pre-implantation genetic diagnosis (PGD) has been given the go-ahead in respect of susceptibility genes like BRCA1 by the Human Fertilisation and Embryology Authority.

The ethics debate continues in respect of the future potential of pre-screening for autism. The Guardian reports on new research which suggests that high levels of testosterone in pregnant mothers’ amniotic fluid could be linked to “autistic traits”.

“High levels of testosterone in pregnant mothers’ amniotic fluid could be linked to autistic traits”

The Cambridge University study looked at 235 children aged between eight and 10, whose mothers had had tests analysing the amniotic fluid around the foetus when pregnant. None of these children were autistic, but those exposed to higher testosterone levels showed higher levels of “autistic traits,” such as poor verbal and social skills.

In response to the calls for pre-natal testing, the NHS Behind the Headlines said: “Even if such a test were possible, it is important to note that this would be a screening test and not a definitive diagnostic test, i.e. it would identify foetuses more or less likely to develop autism rather than identify those who would definitely go on to develop autism.

Screening tests are rarely 100% accurate, and the many ethical issues surrounding prenatal screening for risk of autism would need to be debated before any test could be offered. Also, there are currently no ways to prevent a child from developing autism. Therefore, it is unclear whether identifying children at greater risk of autism would benefit the child or the parents.”

The moral debate will continue with the question arising: “If we screen out autism might we deny the world of a future genius?”

Useful links:
Cancer Research UK – www.cancerresearch.uk.org
Breast Cancer Campaign – www.breastcancercampaign.org
National Autistic Society – www.nas.org.uk
NHS – www.nhs.uk