Want to know whats in your genes? People in the United States will soon be able to buy a genetic test that tells them how likely they are to develop 10 diseases, including late-onset Alzheimers. The saliva-based test is being marketed by 23andMe, a company based in California. The firm already offers spit kits for US-based customers who want to find out about their ancestry or risk of passing on certain genetic diseases to their children. But in 2013, the Food and Drug Administration banned 23andMe from offering a test that assessed a persons genetic risk for 254 disorders and conditions. The FDA was especially concerned by the tests assessment of breast cancer risk a false positive might encourage a person to get unnecessary surgery, for instance, while a false negative might lead someone to be dismissive of breast cancer symptoms. The new test wont assess breast cancer risk, but will screen for Alzheimers, Parkinsons and coeliac disease, and seven other disorders. These diseases were chosen because there is plenty of evidence that genetics affects a persons risk of developing them, says Rachel Reichblum, a spokesperson for 23andMe. The FDAs approval was largely based on this evidence, which included published studies and trials, say FDA representatives. 23andMe also had to show that its tests could correctly identify these genetic variants with at least 99 per cent accuracy. The main challenge will be ensuring that customers can make sense of their test results, and have access to genetic counsellors should they need it, says Brian Zikmund-Fisher at the University of Michigan in Ann Arbor. A requirement of the new FDA approval is that the company provides labelling that provides a recommendation to speak with a healthcare professional, genetic counsellor, or equivalent professional before getting the results of the test, according to an FDA representative. Some argue that if theres nothing you can do to prevent the onset of a disease, youre better off not knowing youre at risk. They say that when people learn this information, it has a significant psychological impact, says Zikmund-Fisher. But for many people, the information is valuable, he says. There are things you can do to manage the experience, such as making plans with family or taking long-term health insurance, he says. 23andMe already markets a similar product in the UK, Canada, Denmark, Finland, Ireland, Sweden and the Netherlands. Each country has different regulations, says Reichbaum.
New Scientist, 10 April 2017 ;http://www.newscientist.com/ ;