09 July 2013

Notes about the BRCA gene mutation and breast cancer

From links bookmarked during the publicity surrounding Angelina Jolie's elective double mastectomy.  First, from a Reddit AskScience thread re the gene:
Everyone has two copies of the BRCA1 gene, which is often pronounced as "bracka 1". This gene encodes a protein that repairs damaged DNA, which is extremely important for preventing cancer. Many alleles (versions) of in BRCA1, as well as the functionally related BRCA2 gene, have harmful mutations that reduce the proteins' effectiveness and greatly increase the risk of cancer, especially in breasts and ovaries, but also in other specific body parts. That's why Ms. Jolie, 37, had her breasts removed even though it was ovarian cancer that killed her mother at 56.

So it's not accurate to say Ms. Jolie's concern was that she "had the BRCA1 gene". Everyone does. What she has is an allele of the BRCA1 gene that is associated with high risk of breast and ovarian cancer.
Next, from a different Reddit thread re the patent:
It's because the patent isnt for the gene sequence, or the genomic DNA, or even the mRNA that is translated in the body. The patent is actually for cDNA, which is not naturally occurring and can only be generated in the lab. Now, this cDNA is made from extracting the mRNA from a person and doing RT PCR... but "modifications" of naturally occurring stuff have huge precedent as being patentable (see all natural product derived small molecule drugs i.e. pharmaceuticals). The current supreme court case is deciding whether or not cDNA should be patentable. But as someone who works in the field of cancer research, and having read the transcripts from the supreme court case, Myriad (the company who owns the patent) has made a pretty strong case, and the justices are SO amazingly out of their element, that I could see the decision going either way.
Details about the Supreme Court case (Association for Molecular Pathology vs. Myriad Genetics) challenging the validity of gene patents.

From a Salon article on the cost of testing:
According to the ACLU, which brought the lawsuit heard recently by the Supreme Court, Myriad actually recently raised the price to over $4,000, despite the fact that “genetic testing technologies have advanced to the point where all 23,000 human genes can be sequenced for $1000.” The test is often covered by insurance, but policies vary, and of course, not everyone is insured... Myriad’s patent on the genes expires in two years, but the Supreme Court’s ruling will set the broader principle going forward. 
And finally, from the Wikipedia page on the BRCA mutation:
Testing is commonly covered by health insurance and public healthcare programs for people at high risk for having a mutation, and not covered for people at low risk. The purpose of limiting the testing to high-risk people is to increase the likelihood that the person will receive a meaningful, actionable result from the test, rather than identifying a variant of unknown significance (VUS). In Canada, people who demonstrate their high-risk status by meeting specified guidelines are referred initially to a specialized program for hereditary cancers, and, if they choose to be tested, the cost of the test is fully covered. In the USA in 2010, single-site testing had a retail cost of US$400 to $500, and full-length analysis cost about $3,000 per gene, and the costs were commonly covered by private health insurance for people deemed to be at high risk.

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...