Small Fiber Neuropathy and genetic testing?

Posted by hypotemusea @hypotemusea, Oct 9, 2020

Hi everyone, it was great to find this forum and all of you wonderful members on it. This is my first post.

I was diagnosed with idiopathic small fiber neuropathy earlier this year. I was wondering if anyone has undergone genetic testing for this condition (specifically the SCN9A and SCN10A genes)? I have an appointment with a geneticist next month. I think I’d find it helpful to look for answers as to the cause of my condition, and if they found any linked genetic mutations it would affect my reproductive choices as well.

Backstory if it’s helpful to anyone: I’m a 27 year-old woman, previously active and relatively healthy but then I started having constant pain in my hands and feet last year. At first my doctor thought it could be RA but then they did nerve conduction studies and QSART test to diagnose SFN. I’ve seen multiple rheumatologists, neurologists, gastroenterologists, etc. I also have some joint hypermobility (I think a 5/9 on the Beighton), especially in my limbs and upper body… I might consider genetic testing for EDS as well. I was diagnosed with PTSD years ago, so I have definitely put my nervous system through a lot. I couldn’t find any research linking it to SFN specifically though.

It’s been really challenging to go from being healthy and active to having chronic pain, and to know that I am only 27 with 50 years ahead of me with this condition and no treatment available. The pain is worst in my hands and wrists so it makes work and everyday tasks painful — I recently quit my job partly because of this. I used to teach yoga part-time and enjoy activities like rock climbing, cycling, even the occasional run for fitness but I’ve had to give up on those things. I’ve also lost almost 10% of my body weight in the past year from this and related stress (I was already borderline underweight to begin with).

Things that I’ve tried: I’ve been receiving acupuncture for about 6 months, most of the time it helps keep the pain to a manageable level although when I get pain attacks (like last month when I decided to go for a run it triggered two weeks of severe pain) even acupuncture is ineffective. For some reason I’ve found that the TCM herbs the doctor prescribes have been more helpful than the acupuncture itself. Lyrica helps me to sleep but doesn’t actually reduce the pain — I can’t tolerate anything more than 50mg due to side effects. Tramadol gave effective pain relief but made me too drowsy and gave me flu-like symptoms even after just once dose. And when I can manage it, very gentle yoga and meditation is helpful.

My doctor prescribed a low dose of amitriptyline but I have yet to try it. It’s more of a “last resort” for me because I’m very sensitive to medications and speaking from experience I have a very hard time with drug withdrawals, even on supposedly low and unproblematic doses. I will likely start taking it next year if my acupuncture shows no further progress.

I would love to hear from anyone who’s had similar experiences! Sending thoughts and good vibes to everyone here 🙂

@hypotemusea

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.

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@hypotemusea
I didn't know how useful that series of posts by the other person would be, but they were the only one I had heard mention genetic testing for neuropathy before you (and Rachel @rwinney , who also said she had it done).

You comment that perhaps your dad got neuropathy simply as a result of getting older is, I think, not valid (I could be wrong). I have known a lot of older people in my life and not one of them ever mentioned having neuropathy. In fact my wife was the first person I had ever known that had it (result of chemo in 2014). That said, I am finding out that MANY different things seem to cause neuropathy, some as unexpected as simply getting an injection or having a vit. b12 deficiency. Weird, eh?

I have not heard or thought of a good reason for genetic testing for neuropathy. Now if identifying the exact gene could result in some type of treatment involving manipulation of that gene or its DNA, that would be different. Otherwise, of what value would knowing the gene have? I'm actually asking whether you know; just because I am ignorant of a reason doesn't mean one doesn't exist.

I hope you can find some relief from your pain. Don't give up on TCM (Chinese medicine) or other alternative treatments for your pain. Do consider or look into med. mariju. (when back in the US) and kratom, or possibly ketamine. Also look into low dose naltrexone (LDN) and palmitoylethanolamide (PEA) both newer treatments some people are starting to get benefits from. (I'm just throwing out things you can research on your own if you want to.) One of the best things you can do for your health is cut down on sugar as much as possible, just FYI. Sugar is a beast on your body.

I hope you find the answers you are after my dear. It's sad enough when anyone has PN, but especially so in a person who's only 27! BTW, if you do ever discover the cause of your PN I'd love to know what it was.

Best to you, Hank

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@hypotemusea

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!

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@hypotemusea it’s interesting you mention PTSD as a potential cause of some autoimmune disorders for some people. I was recently diagnosed with PTSD and I developed 2 potentially autoimmune diseases after some traumatic events in my life. Neither is curable and both are hard to treat. My diseases don’t have a definitive, concrete cause from the medical community but it is awfully suspicious to me.

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@hypotemusea I have changed the title of your discussion to "Small Fiber Neuropathy and genetic testing," for clarity

@helennicola and @lilotter have also been diagnosed with SFN and they may wish to add to this discussion.

You are taking an active role in the management of your Small Fiber Neuropathy through medical and non-medical means (acupuncture, yoga and meditation). You took yet another positive step by joining Mayo Connect as a means to get the answer and support you need.

Small fiber neuropathy has greatly impacted your previously active lifestyle. That must be extremely difficult.

It is wise to be cautious when adding a new medication.

It's important that you and your provider weigh the potential pros and cons.

What did your provider say his hope for adding the medication would be? Does it successfully treat patients with Small Fiber Neuropathy?

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@hypotemusea

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.

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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

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@hypotemusea

@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?

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Agree. Good points! Sunnyflower

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@sunnyflower

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

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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.

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@mjpm2406

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.

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@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

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@jesfactsmon

@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

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I have an appointment at Weil Cornell in Manhattan with a Medical Geneticist on October 26th so I'll mention LDN to her. I was recently diagnosed with Type 4 SMA so now my 4 adult children need to be tested to see if they are carriers of the SMN1 gene mutation. If any of them are their children will then have to be tested. I hope the SMN1 gene mutation ends with me. As far as I know, no one in my family has ever had SMA. It never ends. I have had CMT4B for many years as well as MDS/MPN-RS-T since late 2018. The MDS thing seems to be OK for now. On Hydoxy and my blood counts are within of near the normal range. The CMT thing runs in my family big time. It spares no one on my mother's side of the family. The SMA thing just recently surfaced following a genetic test which the geneticist ordered to see if she could identify a gene mutation that was causing my recent issues with PN. The geneticist wasn't expecting SMA because 95% of SMA patients are children. Further genetic testing is needed to rule out or identify any other neuromuscular gene mutations. Lucky me. Three extremely rare disorders. Almost like hitting lotto. Thanks for the suggestion for LDH.

Regards, Marty

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@mjpm2406

I have an appointment at Weil Cornell in Manhattan with a Medical Geneticist on October 26th so I'll mention LDN to her. I was recently diagnosed with Type 4 SMA so now my 4 adult children need to be tested to see if they are carriers of the SMN1 gene mutation. If any of them are their children will then have to be tested. I hope the SMN1 gene mutation ends with me. As far as I know, no one in my family has ever had SMA. It never ends. I have had CMT4B for many years as well as MDS/MPN-RS-T since late 2018. The MDS thing seems to be OK for now. On Hydoxy and my blood counts are within of near the normal range. The CMT thing runs in my family big time. It spares no one on my mother's side of the family. The SMA thing just recently surfaced following a genetic test which the geneticist ordered to see if she could identify a gene mutation that was causing my recent issues with PN. The geneticist wasn't expecting SMA because 95% of SMA patients are children. Further genetic testing is needed to rule out or identify any other neuromuscular gene mutations. Lucky me. Three extremely rare disorders. Almost like hitting lotto. Thanks for the suggestion for LDH.

Regards, Marty

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@mjpm2406
Marty, you and Sunny @sunnyflower should pool your money and buy some lotto tickets together. She suffers with 3 extremely rare disorders as well (all different from yours I believe), in addition to several less rare conditions, including PN. I am sorry for the burdon all of this puts on you (and your family) and I hope you are able to find the strength to sustain you through the ordeals they present for you. I am glad you will consider LDN, it just might help your pain. Virtually no side effects, just have to obtain it and try it. Best, Hank

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@jesfactsmon

@mjpm2406
Marty, you and Sunny @sunnyflower should pool your money and buy some lotto tickets together. She suffers with 3 extremely rare disorders as well (all different from yours I believe), in addition to several less rare conditions, including PN. I am sorry for the burdon all of this puts on you (and your family) and I hope you are able to find the strength to sustain you through the ordeals they present for you. I am glad you will consider LDN, it just might help your pain. Virtually no side effects, just have to obtain it and try it. Best, Hank

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@jesfactsmon @mjpm2406 @sunnyflower I suspect that out of us human beings have one or more genetic blips. Mine are porphyria cutanea tarda and hereditary hemochromatosis, and I wouldn't be at all surprised if my participation in Mayo Clinic's Tapestry Study (exploring your genes using DNA sequencing) comes up with something else.

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Agreed. One of my son-in-laws and his brother have hereditary hemochromatosis. I was exposed to a significant amount of toxins at Camp LeJeune, NC so I assume some of my gene mutations occurred from drinking the contaminated water at that Marine base. The SMA gene mutation occurs in 1 out of 50,000 people. So many people are carriers of the SMN1 gene mutation. Once identified it’s important to have all your children tested. Just in case.

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@sunnyflower

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

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@mjpm2406 I also don't think gabapentin works for me either but I found a cream I use that's for Neuropathy and Fibromyalgia Topricin cream . Google it or cvs has it Hope it helps you ,helps me

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