CMT is the most common "inherited" peripheral neuropathy. The trouble is that it is misdiagnosed as polio, MS, Fredrick's Ataxia, etc.

I looked up 23 and Me and I do not believe that it would be testing for CMT. As I've said before I have heard that Athena Diagnostics pretty much has that testing sewn up and they are very expensive. There are papers to sign, etc. and they should be read totally and understood before a person agrees to it. Sometimes insurance will pay and other times they won't. DNA blood testing is good if you want to know the sub type. Not really necessary in my view as there is no cure/treatment for any type of CMT as of yet.

Sometimes the DNA testing will neither rule in or out a type of CMT. The most common types CMT 1, CMT 2 and CMT X would be pretty readily interpreted. But others, and there are more than 50 types aren't so easy. Even if the test shows you don't have it, you might if that makes sense. It just might be a type that they do not test for as of yet.

In 2008 from a reputable source stated that there were more than 50 identified types of CMT and no end in sight. CMT can pretty much be separated into two kinds - the "demylenating" forms (CMT1 and CMT4) and the "axonal" forms (CMT2, autosomal recessive CMT2, HSAN, and HMN).

The Vitamin C studies have never panned out. I can't remember off hand the dose given. One trial in The Netherlands used 4 capsules of 250 mg. twice daily equals 1000 mg. during a one year trial. A placebo was used on some and no one knew what they were taking. In some of the trials elsewhere as well people had to get out of the study due to adverse effects, etc. These studies were for CMT1A only. There was much criteria to get into the trials. Other places in the U.S. did a two year study. Here is a site:

http://quest.mda.org/news/cmt-vitamin-c

They have also been doing trials on CoQ10 and CMT. Nothing proven here either.

These trials have not been in the U.S. alone but all over the world.

Your second site on Vitamin C (Ascorbic Acid) trials pretty much says it all. There is really no significant effect. Some CMTers have tried taking a lot of Vitamin C on their own thinking that it could do something for them. But it's in vein. There is much that goes into these trials.

CMT is really considered a rare or orphan disease and some other diseases as well so there is little incentive for drug companies to develop drugs for it. CMT is all over the world. Time will tell.