Angelina Jolie and the Maturity of Genomics
The extraordinary and brave decision of Angelina Jolie to publish an op-ed in the New York Times about her decision to undergo a preventative double mastectomy in response to learning that she carried a defective version of the BRCA1 gene has banished all doubt that we are living in a post-genomic world.
The BRCA1 gene and its related gene BRCA2 are tumour suppressor genes which help in the repair of damaged DNA. Mutations in these genes can hugely raise the risk of developing breast and ovarian cancers and also increase the risk of developing other cancers. The mutations affect the activity of the proteins produced from the genes and with one of its repair mechanisms altered, the cell has a greater risk of accumulating the genetic changes which can lead to cancer. Women who have been diagnosed as carrying this gene can make choices about how to deal with this by taking prophylactic medicinal treatments such as tamoxifen and/or undergoing preventative surgery. Surgeries which have been shown to lower risks of developing cancer include tubal ligation, oophorectomy and mastectomy. All of these include risks that are involved with surgical intervention, however some patients may feel this is justifiable given the considerable reduction in risk of ovarian or breast cancer. This fits into a more general trend in cancer therapy where genetic testing of a person’s cancer can lead to a more specific diagnosis and hopefully a more effective treatment.
The option to take these interventions and the information needed to take them is now taken for granted, however even as recently as the 1990s it may have seemed unthinkable that women could routinely be tested for small mutations. The age of genomics is here, it was born with Bill Clinton standing beside Francis Collins and Craig Venter announcing that the first draft of the human genome was complete. During and since that period, over 6,000 genes have been identified which are involved in disease and the cost of sequencing one base pair of DNA has plummeted from $1 per pair to a fraction of a scintilla of a penny. This confluence holds great hope for those people with rare diseases, for example the Beery twins from California suffered from a type of dystonia that had defied diagnosis. Scientists sequenced their genomes to see why normal treatments for their disorder were not working and discovered mutations which lead to neurotransmitter deficiencies which are easily treatable with existing therapies. That these twins are now able to live normal lives speaks to how far we’ve come in a short space of time.
The lowering of costs of sequencing a genome hold the hope that soon a persons genome will be so cheap to sequence, it could be used routinely by doctors to make diagnosis and treatment decisions. There are already many tests which doctors can use to help inform their treatment options such as pre-natal testing for birth defects or pre-symptomatic testing for a disease that a patient may have inherited such as Huntington’s disease. Pharmacogenomics is a growing field where genetic information is used to help patients and doctors understand which medical treatment may be beneficial and which may carry risk. An interesting example is that of warfarin, a common anti-coagulant, the activity of which varies widely in patients due to genetic differences. However some recent studies have shown that even though genetic testing does help in decisions on dosing, this has little effect on patient outcomes.
For some though, the promises of genomics have been overstated. The gene for Duchenne Muscular Dystrophy was discovered in the mid-1980s and two and a half decades later, there is still no commercially available treatment, although there are treatments currently undergoing clinical trials. Many people believe that despite a general trend in the pharma industry to take a renewed interest in orphan drugs and diseases, some disease causing mutations will simply be ignored for being too rare. The cost of treatments is also a concern, for a rare disease sequencing of the genome may only be a small portion of the cost as analysis of the information may be time intensive and even if the problem is diagnosed, treatment options may not be available. Another issue is that giving patients more information is not necessarily the same as informing them, leading to call for more genetic counselling. This is one reason why commercially available genetic tests remain controversial as there is a fear that someone may worry or take unnecessary action due to a relatively small risk. A patient may worry if they learn their risk of a disease is double the average risk, but this may be unnecessary if the average lifetime risk is 0.005% and theirs is 0.01%.
Angelina Jolie’s story also helps to highlight one of the other issues in genomics: whose property is DNA? The BRCA1 and BRCA2 genes are under a patent held by Myriad Genetics, anyone wishing to have a test for the faulty genes or conduct research on them must pay Myriad Genetics. This has been an enormous issue in both the scientific and legal community. Scientists argue that charging for research on these genes is a barrier which holds back productive science and Myriad’s supporters claim that without allowing people to patent and thus monetise genes, there will be little incentive for industry to invest in genetic research. A court battle has been raging through the US court system for years and is now before the Supreme Court. The findings of this case, whichever way it decides, will likely be one of the biggest decisions in legal history.
There have been many success stories in the short history of genomics and yet many challenges remain to be confronted. Genomics may be maturing, but it has a long way to go until it is grown up.
(Image by Stefan Servos)
What do you think about this story? In what ways can the issue of genetic diagnostics be imporved and advanced? Let us know in the comments below