BRCA questions. Mom is neg. what does that mean to me?

Shabby,

My mom, her sisters, their mother and grandmother had BC. Mom is the only one who survived and is now 82. She refuses to have the test for reasons no one can decipher, so I was tested after my LCIS finding, because I wanted the information to help me decide if I would have oopherectomy, too. My pbmx decision was an easy one with the family history, and I knew I would go forward with that whether BRCA was positive or not.

I learned from the genetic counseling that we have a 50% chance of inheriting the mutation from a parent that has it. So  IF your paternal grandmother or grandfather had it, then your dad had a 50% chance of inheriting it, and IF your dad did indeed inherit it, you have a 50% chance of inheriting it from him.

I am BRCA negative, and there's no BC history on my father's side, so my own son, daughter and granddaughter are in the clear, because their fathers have no BC family history.

My mother's refusal to have the test is causing a stir in family, because I have a brother and his children wonder about themselves and their own children. 

If you are positive, your ovarian cancer odds are increased, so you might consider the test yourself even though your LCIS is already nudging you toward pmx.  My insurance covered the test on the merits of my family history. 

Here's what the Memorial Sloan Kettering Cancer Center site says about the chances of inheriting a BRCA mutation:

What are the chances of inheriting an altered BRCA1 or BRCA2 gene?
Both men and women can pass down a BRCA mutation. All people, whether they have cancer or not, have two copies of both BRCA genes - one copy from each parent. If you have a parent with a BRCA1 or BRCA2 mutation, you may inherit that parent's mutated (nonworking) BRCA gene, or you may inherit the working BRCA gene. In other words, you have a 50 percent chance of inheriting either copy of each parent's two BRCA genes. If you inherit a nonworking BRCA gene, you will have an increased risk for cancer. Even though you may inherit a working BRCA copy from the other parent, it takes only one altered BRCAgene to increase risk for breast or ovarian cancer. You also have a 50 percent chance of not inheriting a nonworking BRCA gene from a parent who carries a mutation. If that is the case you have the same risk for cancer as a person in the general population.

Here's the source for that paragraph:

 http://www.mskcc.org/cancer-care/hereditary-genetics/breast-ovarian-brca1-brca2#toc-item-3

Good luck with this--

Carol 

Hi Shabby,

The main Breastcancer.org site has extensive information on Genetic Testing, including who in the family should get tested, what to do if results are positive and what to do if they are negative, and much, much more.

Hope this helps!

--The Mods

Hi Shabby! Without any other family history of BC or OVCA on your father's side, it seems unlikely there is a hereditary component since your aunt was much older at the time of diagnosis. Any other cancers on your Dad's side?  Not sure why your daughter would need testing for your husband's side, unless his family has a significant family history. You are un-informative negative since your mom does not have a " known mutation", and yet a significant family history with possible un-identified gene origins. Been there, done that myself with a significant family hx. on both sides.  Not a fun place to be, in murky waters. Like you, I worry very much about my daughter too. I've done all I can to make her informed and proactive, but somehow it doesn't seem enough....

Well, both my parents are negative and I'm positive.  They actually did a DNA test on my dad thinking he wasn't my father...he is.  I'm first generation...which is very rare.  I really wonder how rare it is considering everyone who is not tested.

Shabby, since your Mom was affected by BC & she tested negative, yes this means you are negative for a mutation as well. I do not forsee any current reasons for your daughter to be tested. There are lots of BRCA negative familes out there with a significant family history. I am a prime example There are also other genes that have been identified, such as CHEK2 and RAD51C that contribute to hereditary breast syndromes, but its not known to what extent the roles are of these genes. I think we'll hear so much more about them in the near future too. As Carol mentions, genetic counseling is an option. Did your mother have "full sequencing" re-arrangement testing done and/or BART testing? This would be important to know and could have further implications. Take a look at this study below:

Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation.

http://www.ncbi.nlm.nih.gov/pubmed/19088722

Hey Shabby,

 My dad is a BRCA1 carrier....he got tested because my paternal aunt and paternal grandmother had breast and ovarian cancer respectively.  He got the test so that if it was positive I would have that knowledge and decide what I wanted to do with that information.  I got tested in 2011 when I was 31 years old and was also BRCA1 positive.  My mom never got tested because there is no history of cancer in her family.  However, I had a 50% chance of having the mutation because my dad was positive.  In November 2011, I had a prophylactic nipple sparing mastectomy with TE's.  I am scheduled to have my exchange surgery this Wednesday March 14th!  I truly believe knowledge is power and I am so grateful that my dad had my health and well-being in mind when he decided to get tested.   

 http://www.myriad.com/lib/brac/BART%20one%20sheet.pdf

The BRACAnalysis Large Rearrangement Test (BART) was launched to provide a way to detect additional large genomic rearrangements in both BRCA1 and BRCA2.

Although each patient must be evaluated individually based on his or her personal and family history, there is, on average, a less than 1% chance that BART will identify a mutation in a patient who has already had a negative result from Comprehensive BRACAnalysis.

BRCA un-informative negative here & almost 2 yrs. out from my risk reducing NSM's. With a significant family history, dense breasts, and multiple biopsies, I jumped off the surveillance highway for a better quality of life.  My results are amazing, NO regrets, no complications and fabulous care. PM me anytime if u have questions Esmerelda. I feel as though i have lost nothing, but my risks.

"Shabby, since your Mom was affected by BC & she tested negative, yes this means you are negative for a mutation as well."

 
I'm not sure if I'm not reading this correctly, or if I just disagree.  The only history of bc in previous generations on either side was my maternal grandmother.  I got tested because both my sister and I had bc, and I was the younger sibling.  I'm BRCA2 pos.  My sister passed away before she could be tested. My other sister and my mom both tested negative.  ...so, just because your mom is negative doesn't seem to mean an automatic negative for you... at least, it wasn't in my case.  

 My dad chooses not to have the testing done, so I guess I'll never know if I got the gene from him or if I was just "lucky" enough to mutate on my own.