Hi again,

There are so many types of inherited PN yet to be identified (yes, there are tests for CMT - some types, HNPP, some forms of HSN an HSAN etc...) - the trick is trying to nail them all down... I've been asked to have family members participate and get tested by docs who were trying to insolate the speicific mutation - but they are afraid of needles, etc... I think its more of the disease actually that is causing the fear.... but in any case - based on your response to meds, known family history, severity and progresision of the disease, biopsies, other tests etc. can give them very good clue to whether PN is inherited or not. This can help of course with any possible treatment, or at least prognosis as to what you can expect for the course of the disease. Also, IVIG may help some with inherited PN. In any case - they may learn from you if its a type not yet identified.... and be able to help other patients and family in the future...

I understand that IVIG therapy is for "autoimmune" diseases. CMT, for one, is inherited and IVIG treatments are not for CMT. Maybe it helps other kinds of inherited diseases - IDK.

Hope you find some answers.

HI again, I have no auto-immune markers - but the PN did launch following a bad respiratory infection... I know medicare wouldnt have paid for it if the doc didnt have justification - and for some reason it does work on some inherited PN's - maybe if they are heightened by auto-immune trigger? I'll try to find the source!

The Oregon Health Plan won't cover genetic testing because it's so expensive but the neurologist has decided that mine is genetic because it's not diabetic or any other cause he can find. Maybe also because it's receded from causing numbness clear up to my knees and a lot of falling down back down to numbness only to my ankles and no falling just by using 5mg. of prednisone a day. Instead of progressing very quickly like before I took prednisone, it's now stable as of my last visit to him earlier this month. I have a lot of pain and burning if I'm not on my medication strictly, and I don't have good balance. I also can't be up on my feet a lot. But at least now it's not getting worse real fast like it was.

So I was just wondering if there was some kind of name for the genetic kind. I guess it's not that simple.

Oh, and Charcot Marie Tooth was mentioned as early as 20 years ago when I first got sick and then again recently.

No, not that simple as there are many that are genetic

As mentioned, there are a lot of different forms of CMT, but that is a general term you can use for hereditary neuropathies. Another term, less used I think, is HMSN, "hereditary motor and sensory neuropathy". As also mentioned, there's all sorts of different sub-types, and there is some overlap between the two different systems. (Kind of like the Dewey Decimal system and the Library of Congress system for organizing books.) Here's a brief article,
emedicine.medscape.com/article/1173104-overview

In my case, my doctor put in a pre-authorization for a genetic test and it was rejected by my health insurance. But the test is from Athena Diagnostics, who has a program by which they guarantee that the patient's out of pocket expense is limited to 20% of the cost (if you agree to the program and send your payment within 30 days of the test). So, the next time I saw him, he just sent in for the test. I had my blood drawn, received paperwork from Athena about the program, and paid them my 20%. I've received the results (MFN2: negative). I have no idea yet what my insurance company is going to say, but it's not my problem -- a piece of the paperwork allows Athena to argue with the insurance company on my behalf, to convince them to pay.

My insurance company rejected it because the result wouldn't make a difference in my care or in the outcome of the disease -- and I agree that it wouldn't, but it would give me some peace of mind and some understanding of what's causing my symptoms. It's still expensive, tho -- the test cost was $940 and so my 20% was $188.

Athena is the leading provider of genetic tests for CMT and hereditary neuropathies. They have vast panels that will test for everything they can, but my physician has been pretty focused on specific tests relate to my symptoms. You might ask your doc if there are some specific tests from Athena that would be appropriate (so that your 20% doesn't go through the roof).

Here's the scoop on the "Access Athena" program,
athenadiagnostics.com/content/ordering/access-athena

And their main web site is here (you can browse the tests they've got),
athenadiagnostics.com/

(You'll have to copy and paste the links since neurotalk doesn't trust me to post links yet.)

CMT is also known as Hereditary Motor Sensory Neuropathy (HMSN). HMSN is an alternative name for CMT as is Peroneal Muscle Atrophy which was used years back when they didn't know the different types. They only then knew it as CMT and/or Peroneal Muscle Atrophy. CMT is properly used to describe a neuropathy that affects sensory and motor axons. It is not a general term you can use for all hereditary neuropathies.

A few years back, they thought that the term HMSN would sound better than Charcot-Marie-Tooth as some people think it is a tooth problem. However, I find that the term HMSN is not much better as most lay people do not understand it anyway. It is a very complicated syndrome. There should be a better term than either of those in my view. There is much research going on for CMT also known as HMSN.

Your results of MFN2 is CMT2A2. Did the negative mean that you do not have that type? The type 2's are autosomal dominant axonal/neuronal. You probably know this.



http://www.athenadiagnostics.com does do the DNA blood testing for CMT also known as HMSN. There are 22 + types that they now can test for. There are 50 types they have identified so far and no end in sight. And yes, if they have to do the whole panel of tests for CMT that they now can test for, it is expensive. And yes, they do have a program to help with the cost. And your insurance "may" help with the cost.

An informative site: http://neuromuscular.wustl.edu/time/hmsn.html

Have they tested you for HNPP (Hereditary Neuropathy with liability to Pressure Palsies)? It is the opposite of CMT1A which is a duplication and HNPP is a deletion. http://www.hnpp.org I read in your other posts that a part of you (hand) will be numb but then it comes back to normal. This makes me wonder. Something to think about anyway. It's a good site.

Thanks for the info, Kitt, and for your interest. Yes, my negative result for the MFN2 test means that I don't have CMT2A2. A skin biopsy, and nerve conduction testing, indicates that my neuropathy is axonal.

Fascinating info on HNPP. There are some similarities between the symptoms listed and my experience. However, HNPP is "primarily demylenating" and my nerve loss is axonal. I also don't experience any muscle involvement to speak of (though that's variable in HNPP). Still, the info has spawned a new thread of research for me and I'll bring it up with my neurologist the next time I see him.

But I don't really want to hijack this thread... On my 'to do' list is getting all my symptoms and test results together and starting a thread for a review by all the fine folks who hang out here. Right now, my diagnosis is "ideopathic axonal peripheral neuropathy" and I'd like to make the "ideopathic" part go away. Well, I'd like to make all of it go away... Thanks again, Kitt.