Scientists attending a meeting on genomics and public health in London last week criticised some genetic tests being sold directly to the public. According to a report in the Guardian newspaper, tests that claim to assess a person's risk of developing common illnesses - sold via the Internet or through chemists - have been branded 'a waste of money'.
The identification of gene mutations linked to a higher risk of conditions such as cancer and Alzheimer's disease has seen an increase in commercial home-testing kits. However, in most patients, these illnesses are the result of a complex interaction between several genetic and non-genetic factors. For most common conditions, many of the genes involved have yet to be identified, making it difficult to accurately predict an individual's risk.
US scientists based at the Centers for Disease Control and Prevention in Atlanta reported their analysis of two genetic test kits that claim to measure cancer risk. Team leader Muin Khoury said that although each test looks at more than a dozen genes, only two genes appear in both. 'The problem is companies are taking early scientific discoveries and bundling them up into tests too quickly', he said.
Ron Zimmern, director of the UK's Public Health Genetics Unit at Cambridge University, said that even if there is theoretical evidence that the genes are linked to a disease, it was not enough to go on. 'There's not one shred of evidence that these tests benefit human health', he added. 'What line should society take', he asked. 'Should it say that if it doesn't harm you, you can allow the snakeoil salesman? Or does society have an obligation to make sure the consumer is only buying tests that work?' He called upon the industry and government to set up studies to find out whether such tests make any difference to people's health.
Last year, the US Genetics and Public Policy Center called for stronger federal oversight of genetic testing in the country. The centre, based at Johns Hopkins University, wrote to the Centers for Medicare and Medicaid Services (CMS) to issue a proposed rule to create a genetic testing speciality under the Clinical Laboratory Improvement Amendments (CLIA) of 1988. They claim that 'the absence of a specialty area for genetic testing with specifically tailored requirements for the now burgeoning genetic testing industry hampers CLIA's ability to oversee the quality of genetic testing and to adequately ensure its safety'.