If this is your first visit, be sure to check out the FAQ in HCMA Announcements. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. Your Participation in this message board is strictly voluntary. Information and comments on the message board do not necessarily reflect the feelings, opinions, or positions of the Hypertrophic Cardiomyopathy Association. At no time should participants to this board substitute information within for individual medical advice. The Hypertrophic Cardiomyopathy Association shall not be liable for any information provided herein. All participants in this board should conduct themselves in a professional and respectful manner. Failure to do so will result in suspension or termination. The moderators of the message board working with the HCMA will be responsible for notifying participants if they have violated the rules of conduct for the board. Moderators or HCMA staff may edit any post to ensure it conforms with the rules of the board or may delete it. This community is welcoming to all those with HCM we ask that you remember each user comes to the board with information and a point of view that may differ from that which you hold, respect is critical, please post respectfully. Thank you

Announcement

Collapse
No announcement yet.

Genetic screening not always useful or helpful

Collapse

About the Author

Collapse

terryberg Find out more about terryberg
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Genetic screening not always useful or helpful

    I've been told I have HCM, and have been told that it can only be genetic.

    I had the gene testing done, and they were not able to identify the gene that is causing my HCM. I realize that there could be other genes that cause HCM that they have not found yet. I also realize that just because they can't find the damaged gene that is causing this, that it is still likely HCM that I have.

    However, I am a tiny bit less than convinced that what I have is genetic. There has been no sign of it on my genetic tree. And since almost all of the people that I have talked to that also have HCM were able to confirm the diagnosis using genetic testing. I'm wondering if something else has caused this.

    I have no doubt that the myectomy that I'm having on Tuesday 9/27/11, will improve my life immensely, the fact still remains that genetic testing showed nothing in the way of proving I have a genetic disease.

    With this said, genetic screening of my siblings and children is a waste of time and money, since there is no gene to look for since they weren't able to identify the gene that is "causing" my HCM.

    So why are the geneticists still bugging me to have my family screened? I realize it's in my family's best interest to get an echo cardiogram done to rule out any abnormality, but what do the geneticists care? There is no gene for them to look at.

  • #2
    Re: Genetic screening not always useful or helpful

    Hi Terry,
    You're correct about almost all of these points: (1) genetic testing can only find known mutations that contribute to HCM; (2) not all such mutations are known. In fact, about 2/3 of people who clinically have HCM (like you) and are tested are "positive" on the tests -- your experience of being "negative" is a pretty common one. (3) That doesn't mean you don't have HCM, nor does it mean that your disease doesn't have a genetic component. And it certainly doesn't say anything about whether a myectomy will help; if your outflow tract is obstructed, it almost certainly will.

    OK, the one point to quibble about is this. There are two ways you may still have a mutation that causes HCM (although obviously one that's not yet known). First, you may have a new mutation. It's possible and they do occur; in fact, new mutations are where genetic variation originates. So you'd have it but your ancestors wouldn't. Second, a lot -- and I mean an awful lot -- of what's called "gene expression" depends on what other genes are present in an individual, and on environmental influences an individual experiences. Most genes don't simply determine a character, like the blue/brown eyes genes that we learn about as kids (and by the way, that's more complicated than we were taught too). It may be that a mutation has been passed down to you from your ancestors but wasn't expressed in them because they had different environments or because the other genes in their bodies prevented this from happening. This sort of thing is really quite common, but it's hard to study.

    We often think of traits as "being genetic" when there's a strong physical similarity between parents and kids, and "not genetic" when there isn't such a similarity. Biologists (including geneticists) use a different terminology (and for a good reason). We say that a trait is strongly "heritable" when parents and kids are very similar, because we know that it might not be very heritable for the reasons I mentioned. In other words, it's possible for you to have genes that contribute to your HCM, without the trait itself being very heritable. Without the genes, perhaps you wouldn't have the disease, but that doesn't necessarily mean that having the genes makes it *that* likely you'll have the disease.

    There's one other possibility -- it's not impossible that what we call HCM is really a conglomeration of two or more different things, some with largely genetic causes and others with no genetic cause. But there's also no evidence that that's true. In the meanwhile, I'm glad you're having your myectomy!

    Finally, you're right about your final point. If your test was negative, tests of your kids are not going to be informative. I'm not sure why anyone's suggesting otherwise.

    Gordon
    Myectomy on Feb. 5, 2007.

    Comment


    • #3
      Re: Genetic screening not always useful or helpful

      I am gonna guess that I have spoken to a few more people then most about HCM - and the vast majority do not have confirmation of there diagnosis through genetic testing - it is more likely based on anatomy and symptoms. Some have not identifiable family history - but in time this often changes... and new people pop up as time goes by.
      So what has me a bit stumped about your post is this - Ok.. ya had genetic testing and no known mutation was found (as is the case for about 40% of those having testing done) - so likely you are an "unknown mutation" - what has me stumped is this - what testing are the "genetics" people suggesting for your family? IF they want to do a linkage study - to see what genes you have in common with your family and to possible see if a variant of unknown significance is potentially disease causing this makes sense - if they are suggesting clinical evaluation with echo and evaluation with a cardiologist this makes sense - if they are suggesting genetic testing on an HCM panel - this does not make sense.

      Hope to hear your reply.. call if you need anything!
      Lisa
      Knowledge is power ... Stay informed!
      YOU can make a difference - all you have to do is try!

      Dx age 12 current age 46 and counting!
      lost: 5 family members to HCM (SCD, Stroke, CHF)
      Others diagnosed living with HCM (or gene +) include - daughter, niece, nephew, cousin, sister and many many friends!
      Therapy - ICD (implanted 97, 01, 04 and 11, medication
      Currently not obstructed
      Complications - unnecessary pacemaker and stroke (unrelated to each other)

      Comment


      • #4
        Re: Genetic screening not always useful or helpful

        The geneticists might be trying to identify the unknown gene. If they have clinical evidence as to who has HCM in your family (and does not), and they've gene-tested everyone, they might be able to identify the gene by comparing that data.

        Might be worth asking them if this is their intention. Otherwise, it is a waste of time.

        Comment


        • #5
          Re: Genetic screening not always useful or helpful

          They wouldn't succeed in identifying a new mutation by sampling something large like a genome from something small like a family. If it was possible, this might be a common approach.

          Gordon
          Myectomy on Feb. 5, 2007.

          Comment


          • #6
            Re: Genetic screening not always useful or helpful

            Originally posted by gfox42 View Post
            They wouldn't succeed in identifying a new mutation by sampling something large like a genome from something small like a family. If it was possible, this might be a common approach.

            Gordon
            Gordon,
            What if it was a large family? Say 17 siblings, plus when you add in all their kids, that number jumps drastically? Would it make a difference in being able to find a new mutation? I have a very large family. Or would it take thousands with a certain gene?
            Just curious

            Comment


            • #7
              Re: Genetic screening not always useful or helpful

              Hi Aloken35,
              The point I was trying to make, in response to the question Macbeth asked, was about "ordinary" genetic testing. If someone tells you that they want to do "genetic testing" of your family after you've already had the same tests and been found to be be negative, you should ask what the point is and what they could possibly find. This is the point terryberg was making. No, repeating the same sort of test won't lead to identifying anything new. Yes, it IS possible that in a family with an unusually high occurrence of HCM but everyone testing "negative," a new mutation could be identified -- but this would require methods far beyond repeating the same test; it would require some very intense and expensive (no, probably none of us could afford it) molecular biology studies. If that were going on, you should be informed by the researchers (because at this point it would be a matter of your signing papers giving informed consent for new research, not a matter of routine testing). That could be what's going on with terryberg's family, but I doubt it, from the post.

              I'll say it again: if an HCM patient undergoes ordinary genetic testing, and they don't find anything, further genetic study of the family *that consists of repeating the same study in other family members* is pointless, no matter how large the family is.

              Gordon
              Myectomy on Feb. 5, 2007.

              Comment


              • #8
                Re: Genetic screening not always useful or helpful

                The question is, what are the ramifications legally and jobwise along with health insurance? Should we even bother and lose the possibility of losing coverage or life insurance? Or that does not matter once you recieving a diagnosis? Questions, Questions and More Questions.

                Comment


                • #9
                  Re: Genetic screening not always useful or helpful

                  First point: you don't have to tell your employer, or your potential employer, about your HCM. In most cases, it's not a good idea, and in general, they can't ask. In general, you also can't lose your health insurance because of HCM.

                  There is really one, and only one, reason to have genetic testing done at this time, though of course that may change in the future. The reason is because a person (you, for example) have HCM and want to find out whether close relatives may also be at serious risk. If your test identifies a known HCM-causing mutation, then your relatives can be tested for the same mutation. If they don't have it, no worries; if they do have it, they need close follow-up. There's nothing else that genetic testing can presently do, in general: it's not going to tell your doctors how to treat you, in particular.

                  Gordon
                  Myectomy on Feb. 5, 2007.

                  Comment


                  • #10
                    Re: Genetic screening not always useful or helpful

                    This reply is in response to Lisa's reply on 10/17/11. I am happy to help the geneticists out by having my entire family tested. They can then compare our genes to see what we have in common. However, this is going to do no good for any of us except the research community, which will ultimately (in 50-100 years) help others before they develop HCM. So why is it me and my family (or our insurance companies) have to pay for the testing? I mean, here we are in this society that is threatening to go Socialist, and I am being asked to pay for genetic research, and provide the subject of study. Does that sound right to you?

                    Comment


                    • #11
                      Re: Genetic screening not always useful or helpful

                      Terry, I think what Lisa is saying is that there is no need to have your family genetically tested against the HCM known mutation panel if you (the one with HCM) don't have an identified genetic mutation that causes HCM. I have no idea why your family should be genetically tested at this point, unless something changes and your mutation is identified. That doesn't make much sense. Unless they are trying to see what genes you have in common with them, and to maybe identify a previously-unknown mutation.

                      Are these geneticists part of a research project or do they want you to go a clinical route?

                      If they are suggesting your family members be tested via echo and ekg, that makes total sense. When in doubt of genetic status, look at the heart to see what's going on in there.
                      Reenie

                      ****************
                      Husband has HCM.
                      3 kids - ages 23, 21, & 19. All presently clear of HCM.

                      Comment

                      Today's Birthdays

                      Collapse

                      Working...
                      X