Multiple Mutations?

Mommy2Six

Multiple Mutations?

Mommy2Six

hi everyone. Just had my appt with the genetic counselor. Unfortunately, breast and other cancers run on both sides of my family. Based on her calculations, i have a 58% chance of BRCA mutation using just my father's family data and a 26% chance of a mutation using my mother's family data. Is it possible to have multiple mutations, for example both BRCA 1 and BRCA 2?

anneoftheforest

Yes, it is possible to have both, but it is not very common. On the FORCE website forum, which is a hereditary breast and ovarian cancer website I have read posts from woman who have both. It is a great website even if you don't have BRCA mutations but have a strong family history. www.facingourrisk.org

From my understanding if a person has both mutations the risk for any given type of cancer is the higher risk of the two genes. Are you waiting for your test results?

Mommy2Six

Hi, thanks so much for responding!
Yes, I am waiting on my results from Myriad. They were supposed to come today, but did not. I contacted my Myriad rep and she said she had already asked her supervisor to call the lab and find out why my results were not available, but she didn't get back to me before the end of the day.
If someone has both mutations, does that mean their children have a 100% chance of inheriting one of them?

anneoftheforest

Waiting is hard! I hope you get your results soon. No, your kids wouldn't have a 100% chance of becoming BRCA+. Any mutation you would have, there would be a 50% chance of your children inheriting it.

Mommy2Six

Ok that's a relief. I didn't know if it would be impossible for them to not have a mutation, if I didn't have a normal copy of the BRCA gene to pass down to them because I inherited a faulty copy from each of my parents. Know what I mean? I'm still trying to understand all of this!

anneoftheforest

It is confusing and I'm no expert so please run all this by your genetic counselor. I think it is really uncommon to have both at once so hopefully this won't be the case. You have two copies of each BRCA1 and BRCA2 gene, they aren't the same gene named 1 and 2. They are different genes and they even repair DNA differently. If you had a mutation on either BRCA1 or BRCA2 it would be on one of your two copies. BRCA mutations are dominant so you don't need two parents to get the mutation. With this being said there are some people that have two BRCA2 mutations and it causes a more complicated syndrome but it only happens 1 in 350,000 live births so it is very, very rare. There are no known cases of a person with two BRCA1 mutations.

If you were to get the BRCA1 mutation you would have one mutated gene and one unaffected one, so 50% chance for each child to get it from you. If you also for some reason were to get a BRCA2 mutation you would have the same situation as above ... they would have a 50% chance to get the BRCA2 mutation from you.

I hope this helps a bit

Danaw24

I have both a brca1 and brca2 mutation.