The Danger of Knowing Too Much: Prenatal Genome Sequencing

In sooner than a decade, medical experts predict that parents will be able to know the entire gene sequence of their unborn child with a simple blood test. This test, known as prenatal genome sequencing, will allow geneticists to determine a child’s risk of developing certain diseases. Genetic variations may also reveal information about other traits of the child, such as athletic ability and intelligence. 

Eventually, prenatal genome sequencing is expected to cost as little as $1,000, making it an affordable option for millions of parents. Bioethicist Arthur Caplan believes that it will be “the most controversial topic in 20 years.” But in the Hastings Report, scientists at the National Institute of Health cautioned that the issue be addressed now.  Currently, prenatal testing is only used to diagnose genetic disorders for which a child has an elevated risk, such as Down syndrome or cystic fibrosis. This “diagnostic” testing is not controversial, except that the knowledge could prompt the parent to terminate the pregnancy. 

According to the Hastings Report, "Prenatal whole genome sequencing differs from current prenatal genetic testing practice in a number of ethically relevant ways." The most remarkable difference, the report says, is the drastic increase in the “volume and scope of prenatal genetic data.” Though this knowledge could be useful to parents who are preparing for a child, experts fear the exposure to too much information could lead to excessive anxiety. 

About 20,000 to 25,000 genes make up the human genome. Yet scientists know nothing about 90% of these genes, and often the expression of more than one gene contributes to a disease or trait. Geneticists say that most genetic variations are harmless, and have no effect on a person’s health. A problem with sharing prenatal genetic data with parents is that the knowledge could generate unnecessary fear in expectant parents, which may transfer to the child. Another point of controversy is the discovery of traits unrelated to medicine. Some doctors fear that prenatal sequencing could reveal undesirable traits children, leading to more terminated pregnancies. Also if a child’s genes indicated a higher level of intelligence or athletic ability, would this change how the parents raise that child? Undoubtedly, prenatal genome sequencing has important implications for future parents.

The potential benefits in preventive medicine, on the other hand, are enormous. Prenatal genome sequencing is expected to improve detection of serious genetic disorders, allowing parents to begin “preventative care plans.” Genome sequencing data could also indicate a risk for a medical condition that could affect health later in life, such as Alzheimer’s disease or cancer. Early detection—and possibly prevention—of serious genetic diseases could benefit countless children and their families.

The disclosure of medical information found in the prenatal genome is certainly beneficial to parents who wish to know. But knowledge about genetic traits that have nothing to do with health or medicine is a different matter. Exposure to the vast information contained in the genome could be dangerous to ordinary people who have limited understanding of genetics. And the idea of parents making decisions or judgments about unborn children based on their genes is frightening. Obviously, strict rules need to be put in place regarding exactly what information is revealed to parents from prenatal whole genome sequencing. The less people know, the better. 

http://www.foxnews.com/scitech/2012/08/28/prenatal-whole-gene-sequencing-raises-thorny-ethical-questions/

http://www.ama-assn.org/amednews/2012/08/27/hlsb0827.htm