Guest guest Posted August 1, 2009 Report Share Posted August 1, 2009 Since HNPP is a deletion in the region of containing PMP 22 and this deleted region is identical to region duplicated in CMT IA it is dominantly inherited. http://neuromuscular.wustl.edu/time/hmsn.html#pp 20% of Persons affected with HNPP & PMP-22 deletion have de novo mutation (a genetic mutation that neither parent possessed nor transmitted, also known as 'spontaneous mutationnnnn') http://en.wikipedia.org/wiki/De_novo http://en.wikipedia.org/wiki/Mutation http://www.charcot-marie-tooth.org/about_cmt/hnpp.php http://www.hnpp.org/ http://www.hnpp.org/genetics.htm http://www.hnpp.org/gentest.htm For more info contact a genetic counselor. > > What would happen if one parent had CMT and the other had HNPP? > Or if both parents had HNPP? > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 2, 2009 Report Share Posted August 2, 2009 so people with cmt1a have hnpp, that is what has been happening to me, arm hand legs feet going to sleep all the time. i dont have to be doing anything and they go to sleep, it wakes me up at night all the time. From: Date: Sat, 1 Aug 2009 17:23:04 +0000 Subject: Re: CMT and HNPP Since HNPP is a deletion in the region of containing PMP 22 and this deleted region is identical to region duplicated in CMT IA it is dominantly inherited. http://neuromuscular.wustl.edu/time/hmsn.html#pp 20% of Persons affected with HNPP & PMP-22 deletion have de novo mutation (a genetic mutation that neither parent possessed nor transmitted, also known as 'spontaneous mutationnnnn') http://en.wikipedia.org/wiki/De_novo http://en.wikipedia.org/wiki/Mutation http://www.charcot-marie-tooth.org/about_cmt/hnpp.php http://www.hnpp.org/ http://www.hnpp.org/genetics.htm http://www.hnpp.org/gentest.htm For more info contact a genetic counselor. > > What would happen if one parent had CMT and the other had HNPP? > Or if both parents had HNPP? > _________________________________________________________________ Get your vacation photos on your phone! http://windowsliveformobile.com/en-us/photos/default.aspx? & OCID=0809TL-HM Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 3, 2009 Report Share Posted August 3, 2009 This is an interesting question though. What would happen if a person inherited CMT1A from one parent and HNPP from the other parent? Both diseases are autosomal dominant and they both impact the same gene, but one creates an over-duplication problem while the other creates a deletion issue. Would they offset each other? I know genetics aren't that simple, but it is an interesting supposition. My guess is that CMT1A would likely dominate, as a more complete defect, but it's just a guess. What if they did offset each other and it could actually lead to a cure by introducing one into the other through genetic engineering? I know I'm wildly speculating, but I found it an interesting question. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 3, 2009 Report Share Posted August 3, 2009 It's a cool idea. My neuro for 5 years thought I had CMT, only after the Athena Labs test was it determined I have HNPP. I have a very unstable gait (walk like s drunk) with zero bslance so I use a 4-wheel walker, severe numbness below knees and hands, very weak hips so I can't walk too far, tire easily, my fingers feel like jelly and the tips are numb, I have drop foot and hammer toes, really lots of the same issues as CMT. That's why my doc said it's hard to tell exactly which one you have without genetic testing. But the bottom line is, both are debilitating; so I'd love to see a study on playing with that gene. The only benefit with HNPP, for me at least, is I do not have any pain, I just don't have any feeling. But I know people with cancer, so I can't complain too much. I guess it could always be worse. Jeanne Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 4, 2009 Report Share Posted August 4, 2009 , this is what I was wondering about. would they cancel eachother out? would they create a 'new' genetic disorder? I also wonder what would ahppen if both parents habe CMT or if both parents have HNPP. I am curious because I have HNPP. I inhereted it from my father. But at first I thought I inhereted it from my mother because she has SEROIUS high arches and hammer toes and a few of the other symptoms. this was my assumption until I contaced my bio father and found out he has serious neuro problems. Bree-Anne Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 4, 2009 Report Share Posted August 4, 2009 I'm just the opposite (not in symptoms but diagnosis). I had self diagnosed HNPP and convinced my neuro to do the genetic test for it. She ordered the peripheral neuropathy panel and wouldn't you know it, CMT. Well, I was pretty close, same chromosome, same gene even. Holli Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 5, 2009 Report Share Posted August 5, 2009 Hi Bree-Anne, These are very good questions. You mention that you have HNPP. Was that diagnosed through genetic testing? Have either of your parents been diagnosed with HNPP or CMT through genetic testing? What does your neurologist think about this situation? Even if both parents have CMT or HNPP, it doesn't necessarily mean you got two bad genes. There's a 50% chance you inherited one bad gene for either parent, but only a 25% chance you were lucky enough to get both of their bad genes. If you do have two bad genes, I'm sure your situation would be one the medical community would be quite interested in evaluating, since it's very rare. If it were me and insurance would cover it, I'd try to get as much medical information from each of my parents as I could, i.e. Nerve Conduction Velocity/EMG test results, any genetic testing results, clinical reports, etc., and take it to my neurologist for evaluation and try to get an answer, if possible, for myself through genetic testing. Since testing for every currently identifiable type of CMT in addition to HNPP can be expensive, the neurologist may be able to look at the combined medical information of all three of you and rule some things out automatically. Once you have an accurate diagnosis for yourself through genetic testing, then you may be able to get more answers. In addition, if you are thinking about having children in the future, you may want to know if you carry two defective genes. If you have two defective genes of the same type, i.e. two HNPP genes or two CMT1A genes, one from each parent, then you would have a 100% chance of passing a defective gene on to your children, which could be helpful information to know if you do have kids. Hopefully your doctor can help you find some answers. If so and you're comfortable sharing with us, it would be interesting to hear what you find out. From: scottbree <scottbree@...> Subject: Re: CMT and HNPP Date: Tuesday, August 4, 2009, 6:41 AM , this is what I was wondering about. would they cancel eachother out? would they create a 'new' genetic disorder? I also wonder what would ahppen if both parents habe CMT or if both parents have HNPP. I am curious because I have HNPP. I inhereted it from my father. But at first I thought I inhereted it from my mother because she has SEROIUS high arches and hammer toes and a few of the other symptoms. this was my assumption until I contaced my bio father and found out he has serious neuro problems. Bree-Anne Quote Link to comment Share on other sites More sharing options...
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