I may have found my SFN cause
 

Hi all,
I have been to more specialists than I want to count. I had 2 skin biopsies but both were negative.
I participated in a study done by xenon pharmaceuticals for a rare condition called Erythromelalgia. Essentially, Erythromelalgia is a condition where a part of the body , usually feet, get hot and turn red and burn.
Anyway, the study showed that I don’t have the gene they were looking for, but I do have a deletion in the scn9a gene that encodes for the nav 1.7 sodium channel. Crazy complicated.
I guess my doctor at Mass General is now looking into that deletion as my possible cause of SFN and Erythromelalgia since that gene has been implicated in these conditions.
She believes SFN is a symptom of another issue. Erythromelalgia is a symptom
If SFM
She has never seen this deletion before, but is brining my case to the neuropathy conference in Italy.
I have no idea what the future holds for me.
My nerve fibers don’t appear to be damaged, at least not at last testing, but they mis-fire

Currently having a feeling of a horizontal line under my foot .
It could be related to plantar fasciitis but one never does know with this crazy condition,
I think I’m non length dependent as I started with hypersensitivity in the front of my thighs and my feet would burn.

Anyone like me?
I’m a very rare bird😂

Goosiegoo, it is good that you have made some progress in understanding your SFN.

An association between erythromelalgia and SNC9A mutants has been reported.

The information in this (slightly technical) link might help you with this.

Inherited erythromelalgia due to mutations in SCN9A: natural history, clinical phenotype and somatosensory profile | Brain | Oxford Academic

Thanks for sharing this information, Goosiegoo.

Do you have any exact information on your deletion? It might look like something below. The last mutation I show is an insertion I have.

SCN9A: c.=
SCN9A: c.2072-14C>T
SCN9A: c.174G>A (p.(=))
SCN9A: c.444A>G (p.(=))
SCN9A: c.1942-3_1942-2insT (insertion)

When you say "hypersensivity in the front of your thighs," can you describe that more please? I have hypersensivity as well from my torso on down. If I touch on side of my body from that point down, I get sensations in my feet. And actually, the same goes for just moving. By that I mean, if I move my left shoulder causing my torso to twist on the left side, I get sensation in my left foot. The same goes if I touch my left thigh.

If skin biopsies negative x2, where did the diagnosis of SFN come from and what were the symptoms that led to that diagnosis?