--though it's not as typical for the hereditary neuropathies to hit with a sub-acute onset, as yours seems to have (though, admittedly, the presentation of hereditary neuropathies is highly variable).

It does sound to me, though, as if your situation is more likely due to either a toxic or autoimmune dysfunction (and toxic can include prescription drugs, not just the usual suspects like heavy metals or organic solvents).

You have had a lot of testing--Mass General has a good department when it comes to neuropathy investigation--but I did not see the testing for metals or for the antibodies specific to peripheral nerve in there. The Liza Jane spreadsheets at www.lizajane.org have these, and Dr. Latov's Quest Laboratories application paper also lists them:

http://www.questdiagnostics.com/hcp/...eralNeurop.htm

Often, in these sorts of situations, when the standard rheumatological antibody tests don't show anything amiss, the more advanced nerve antibody tests are indicated (and not a lot of rheumatologists are familiar with them).

And, yes, it's good that the neuronopathy--that is, attack on the cell bodies themselves in the ganglia, not just the fibers--has been mentioned; this does seem to happen in a certain percentage of fast onset, body-wide neuropathies, often due to Sjogren's, or, unfortunately, to cross-reaction with substances produced by tumors (I would think the anti-Hu, anti-Ri, and anti-Yo tests shold be done, and a survey for tumors considered, just to be safe--I had all these done but I had to go to Cornell-Weill for the doctors to know what I was talking about--no positives, fortunately, and now it's 7.5 years later).

A significant portion of these acute-onset neuropathies wind up being idiopathic, with autoimmune mechanisms suspected, but hard to prove--you may be producing antibodies unique to your nerve structures. That is, unless, you had some sort of traums that would point to compressive causes, especially in the spine. Unfortuantely, spinal compression, or even compression of multiple spinal nerve roots, can produce symptoms that "feel" exactly the same, and it's one reason a series of MRI's is often an early step in these kind of cases--and it's an opportunity to check for central nervous system demyelinating diseases such as MS as well.