BRCA1 Gene Mutation
I have a BRCA1 gene mutation, and it is the cause of my breast cancer at such a young age.
My husband posted a summary of what that means on the blog. The following is an excerpt from his post 4 Aug, 2014 (find full blog post here):
Last week, Lori finished the required paperwork and family history prerequisites for proceeding with the BRCA 1/BRCA 2 gene testing. The results of this test have huge implications, not as much for Lori but for her living blood relatives and their children. No one in her family has ever been tested, but ovarian and breast cancers have been appearing among her relatives, and since Lori was diagnosed at such a young age, it raises even more alarms. The BRCA mutation is incredibly fascinating; well, maybe horribly fascinating is a better way to describe it.
A mutation of the BRCA gene can take many forms but often it is linked to women who experience breast or ovarian cancer at relatively young ages. It is also very rare. About 80% of women diagnosed with breast cancer have a sporadic case of breast cancer, or in other words, the breast cancer developed by chance. About 5-15% of women developing breast cancer do so because of familial risk. Familial cancer occurs when several family members have cancer, but the diagnoses do not occur at young ages/or do not occur in a clearly defined inheritance pattern. Individuals in families with familial cancer are considered to have a moderately increased risk for developing cancer. Only about 5-10% of women developing breast cancer do so because they inherited a genetic mutation that increased their breast cancer risk. A mutation is a change in a gene which causes that gene to function incorrectly which may result in a particular disease developing. In the case of the BRCA genes, it often causes breast or ovarian cancer.
The test is a simple blood draw which they use to analyze a bunch of DNA stuff associated with BRCA genes. Every human has two copies of both the BRCA1 and the BRCA2 gene. For visual learners, imagine two healthy copies of the BRCA1 gene are annotated as “AA” (two uppercase A’s to represent two healthy copies of the BRCA gene). If there is a mutation of one of those copies, it would be annotated as “Aa” (one healthy copy and one mutated copy). Here’s an example of how that might affect a family:
Let’s say a woman named Mary carries two copies of BRCA1 and hers are both healthy (AA). Her husband, we’ll call him John, carries the mutation so one of his copies is bad (Aa). When Mary and John make a baby (we’ll call the baby girl Flubus) they will each donate one of their BRCA genes to the baby so that she also will carry two copies of the gene just like every other human. Unfortunately for little Flubus, there is a 50/50 chance that her dad John will pass along his mutated copy (a); if that happens, then baby girl Flubus will also have the mutation. So it’s a 50/50 chance that Flubus gets it. And it’s a 50/50 chance for each of Flubus’ brothers and sisters as well. Now if Flubus grows up and gets tested and finds out that she is positive, that has huge implications for the rest of the family. First of all, that means one of her parents gave her the mutation. It also means that each of Flubus’ siblings has a 50/50 chance of having inherited the mutation as well. But the fun doesn’t stop there. If Flubus wants to have kids, she has to understand that there will be a 50/50 chance of passing along the mutation to each of her children (boy or girl doesn’t matter). Men are just as likely to carry the mutation as women, but they are unlikely to be harmed by it since they generally have neither breasts nor ovaries. One of my sisters-in-law sent me this link further explaining what one can do if they test positive: Positive BRCA Result. For women who find out they are positive but they don’t yet have cancer, some decide to have double mastectomies (see Angelina Jolie) and some even have hysterectomies. There are gatherings and conventions and tons of research projects out there all focused on curing and treating those affected with BRCA mutations.
Now for me (Lori), it doesn’t really matter all that much. I already have cancer. However, there are certain cancer pathways which are often heavily traveled by cancer cells in women who have tested positive for a BRCA mutation. There are also some new and exciting trials in which women who are BRCA positive have used PARP inhibitors (a medicine) to block those pathways, and it appears to be working very well in many cases. So, it was both good and bad that I tested positive because it opened up new treatment options for me.