Small Fiber Neuropathy and genetic testing?

Hi again @hypotemusea I did find that person. It was @mjpm2406 and you can find what they posted on their profile page describing some things about the genetic testing they had done, linked here:
https://connect.mayoclinic.org/member/180562aa00519da84045fb752d7c78c086a35d706c/
Not sure if that person is still paying attention to Mayo Connect at this point. But you can try to use their Mayo name @mjpm2406 in a post and perhaps he/she might contact you or at least post a reply. -Hank

@sunnyflower You're right that once a doctor is confident in a diagnosis that they wouldn't see further testing as necessary. The first neurologist I saw declined to do a nerve biopsy for me (although I understand it's standard with doctors in the US) because to him my diagnosis had already been confirmed by the QSART test.

For genetic testing I think it could make a difference in the diagnosis? If they identify a genetic link then maybe there's no need to turn over every stone looking for hidden autoimmune or neurological causes?

Thanks! This is really helpful! I searched for keywords like SCN9A and SCN10A but didn't find much in terms of people's experiences of undergoing genetic testing. My father (in his late 60s) has some mild neuropathy in his feet, and his mother had some diabetic neuropathy. I assumed that my father's mild neuropathy is an age-related thing but maybe it isn't? As far as we know no one in my family has had the same sort of neuropathy at a young age.

My geneticist seems willing to help -- I had a previous appointment before where we discussed testing for Ehlers-Danlos, but I didn't know until recently that apparently 30% of people with SFN have the SCN9A genetic mutations (I couldn't find the research source, although it's mentioned on the websites of the genetic testing labs) and 5% with SCN10A... Even if the figure is not entirely accurate, 35% sounds significant enough for me to consider testing. And preliminary research has shown correlations between Ehlers-Danlos and SFN diagnoses too.

My doctors didn't try gabapentin. Lyrica was the first and (only?) nerve pain medication that I've tried. I'm seeing a new neurologist soon who specializes more in PN issues, so I'll definitely bring it up to him.

Hi Jennifer, thanks for all the info and advice! You are right that Lyme is a possibility. I lived in Eastern US for several years where I was outdoors a lot and also lived for some time in South American jungles and forests, although my home country is in Southeast Asia (where I currently am). I have friends who've dealt with chronic Lyme complications so I'm aware of how bad it can be. In my country here there's not as much awareness. I took a Lyme antibody test here, and it came back negative, although of course that doesn't really say anything like you pointed out.

As far as I'm aware I've been bitten by ticks twice, first time in upstate NY in 2015 and second time in rural Guatemala in 2018, I immediately took antibiotics the first time (having seen what Lyme can do I didn't want to take chances!) but not the second. My hunch is that it isn't Lyme because I don't really have joint pain? My main symptoms are the nerve pain, tingling, constant burning sensation in my hands and feet. I feel that the pain is more nerve-related, not so much the joints. I have pain in my elbows but they were very hypermobile so that might be the culprit. I don't really have any symptoms in the larger weight-bearing joints, fortunately. My rheumatologists did an ultrasound for my hands to look for inflammation and there was none. Steroids and anti-inflammatories had no effect on my pain.

So there's not much I can do to further the Lyme investigation for now while I'm here, but when I return to the US I'll definitely seek out a more experienced Lyme practitioner if my health issues still persist.

And thanks for bringing up PTSD as well. It's why I suspected RA at first given the documented links between PTSD and autoimmune diseases like RA... but I've done many comprehensive blood and antibody tests to find evidence of autoimmune issues and they all came back negative. It's certainly possible that I have something autoimmune going on that those tests are not finding, but I'm confident to rule out the big culprits like lupus and RA for now. It's certainly a detective hunt!

Thanks! This is really helpful! I searched for keywords like SCN9A and SCN10A but didn't find much in terms of people's experiences of undergoing genetic testing. My father (in his late 60s) has some mild neuropathy in his feet, and his mother had some diabetic neuropathy. I assumed that my father's mild neuropathy is an age-related thing but maybe it isn't? As far as we know no one in my family has had the same sort of neuropathy at a young age.

My geneticist seems willing to help -- I had a previous appointment before where we discussed testing for Ehlers-Danlos, but I didn't know until recently that apparently 30% of people with SFN have the SCN9A genetic mutations (I couldn't find the research source, although it's mentioned on the websites of the genetic testing labs) and 5% with SCN10A... Even if the figure is not entirely accurate, 35% sounds significant enough for me to consider testing. And preliminary research has shown correlations between Ehlers-Danlos and SFN diagnoses too.

My doctors didn't try gabapentin. Lyrica was the first and (only?) nerve pain medication that I've tried. I'm seeing a new neurologist soon who specializes more in PN issues, so I'll definitely bring it up to him.

@sunnyflower You're right that once a doctor is confident in a diagnosis that they wouldn't see further testing as necessary. The first neurologist I saw declined to do a nerve biopsy for me (although I understand it's standard with doctors in the US) because to him my diagnosis had already been confirmed by the QSART test.

For genetic testing I think it could make a difference in the diagnosis? If they identify a genetic link then maybe there's no need to turn over every stone looking for hidden autoimmune or neurological causes?

Hello @hypotemusea, @jesfactsmon, @mjpm2406 I found Lyrica to have the identical side effects that Gabapentin did. But I don't think it helped as much with the pain. Hope it works for you. It does for a lot of people. Many blessings, fondly, Sunnyflower

Gabapentin and Lyrica don't work for me. My nerve pain us tolerable during the day. At night it's really bad. I can't sleep in a bed but I can sleep on a recliner. So for now it's tolerable although my wife doesn't like the fact that I sleep on a recliner every night.

@mjpm2406
Well, she might not like it (that you sleep in a recliner) but it's not that uncommon, I have heard a few other people with neuropathy mention being more comfortable sleeping on one. Sleep is SO IMPORTANT that wherever you can get the best rest is exactly where you should sleep IMO, whether a recliner, the floor or a park bench.

If you do not use any opioids for your pain you might want to consider trying low dose naltrexone (LDN), have you heard of it? There is a discussion on Connect linked here: https://connect.mayoclinic.org/discussion/low-dose-naltrexone-and-neuropathy/?utm_campaign=search

It's to be taken at night I think, and involves getting your body to produce more endorphins, which would help pain theoretically. I think some people have had good luck with it (and some have not, of course). My wife is going to be starting it soon I believe. She has the prescription here at home waiting to be started but is waiting to get through trying one or two other things first so as not to be confused as to which effects to attribute to which drug or supplement. Just thought I'd pass that along since you are having so much trouble at night with pain.

Best, Hank