Genetic testing for incidental illnesses challenges medical ethics

Increasingly powerful genetic tests are raising ethical questions for doctors who are starting to find out more about what could be in store for people's health, including predispositions for mental illnesses and cancers.

Researchers at the Murdoch Childrens Research Institute say genetic tests being used to study developmental delays in thousands of children each year can now reveal many ''incidental findings'' that the children and their parents may or may not want to know.

The tests could also reveal information that leads to more testing of family members that may alert them to a higher probability of illnesses such as schizophrenia, autism or heart disorders that they did not know existed in their family tree.

Traditionally, doctors ordering genetic tests have looked at specific genes that would aid their investigation of particular symptoms, and patients would specifically consent to those genes being investigated. But newer gene sequencing technology is now making it cheaper and more efficient to look at someone's entire genome, making incidental findings inevitable.

In response to this, the American College of Medical Genetics and Genomics recently released new recommendations saying that unless patients specifically ''opt out'' of incidental findings being analysed, all genome sequencing tests taken for any medical reason should examine 57 other specific genes to look for incidental findings such as the BRCA 1 and 2 gene mutations that cause a high risk of hereditary breast and ovarian cancer. The list includes gene variants that cause a higher risk of bowel cancer, eye cancer, thyroid cancer and heart disorders that often cause sudden death.

While the recommendations do not control the actions of Australian health professionals, experts say the same powerful genetic tests are being used in an ''ad hoc'' fashion in Australia with no specific protocols governing how consent should be managed or what information should be passed on.

However, Erin Turbitt, a researcher at Murdoch Childrens Research Institute, said a survey of 59 Australian genetic health professionals found the main driver governing decisions about what information should be shared from children's tests was whether preventative measures and treatments were available.

The head of the Victorian Clinical Genetics Services, David Amor, said with about three new genes being discovered each week, the power to detect predispositions for psychiatric disorders and learning and behavioural problems was increasing rapidly.

For this reason, he said it was important to differentiate between what was useful medical information that could lead to preventative medicines, for example, versus information that could be harmful.

''Once you've told someone about something like [schizophrenia or autism], it's very hard to put the genie back in the bottle … and we don't know what happens to these people months and years after giving them this sort of information. '' Associate Professor Amor said.

Incidental findings

Possible findings include gene variants that predispose people to:
Autism
Alzheimer's disease
Schizophrenia
Breast cancer
Ovarian cancer
Bowel cancer
Fatal heart conditions