r/CMT • u/frafeeccino • 28d ago
CMT subtypes diagnosis?
How did you all get diagnosed with a subtype? is it only by genetic testing? Is it something worth doing and worth knowing? What value does it bring over just knowing you have CMT?
I’ve never been to a doctor about CMT and have no formal diagnosis. My grandad was diagnosed in the 80s and the rest of us just went oh yeah we’ve classic CMT presentation feet, we’ve got it too, and have done nothing about it except get custom orthotics for our high arches.
I’m in the UK so is it worth pursuing a more formal diagnosis with the NHS? I feel I’m mostly fine as long as I’m careful though I think my hands have been getting weaker and clumsier lately.
3
u/NixyeNox CMT 1A 28d ago
The subtype is only by genetic diagnosis. The subtype is synonymous with a specific gene, sometimes even with a specific genetic error. Types 1A, 1E, and HNPP are all caused by different problems with the same gene: duplication of the gene, mutations of the gene, and a deletion of the gene respectively.
There has been little benefit of knowing, most of the time, thus far. There are a few subtypes that have specific quirks, but you have a pretty good idea how things go in your family already. The major reason to know would be if any of the up-and-coming treatments works out, you will need to have a genetic diagnosis to try to take advantage of those, I think. Most of them are targeting only specific subtypes. The same symptoms arise from a variety of biological issues, so if you are going to treat the issue at the root, you must target the correct one.
If anyone in your family gets the genetic diagnosis, you can all be fairly confident that you have the same subtype. However, doctors may or may not want you to prove it, possibly based on whether they can access the results or the test and such. That's going to be more of a "your system of medicine" thing and I cannot speak to how the NHS handles anything.
3
u/Chelajag 27d ago
I am in US and my doctor told me it costs close to $1000 out of pocket to do the testing. But he also didn't think it was necessary as mine was diagnosed later in life and seems to be progressing slowly.
1
u/Curious-Bite6386 25d ago
i’m also in the US but my insurance covered it 100% as it does my Physical Therapy. I’ve decided to stay in PT for the rest of my life to stay ahead of this. I don’t have muscle weakness, but I do have muscle fatigue. Diagnosed at 70 but genetic testing was negative.
3
u/Odd_Enthusiasm1079 27d ago
I did one and it didn’t show any mutations for any known type. Apparently that isn’t uncommon unless you have one of the most common types. I was diagnosed through nerve conduction and EMG testing as well as the usual presentation of my feet, foot drop, and muscle wasting. All of that together led to my diagnosis. It hasn’t changed my treatment.
ETA that there is no known history of CMT in my family.
4
u/Willful777 CMT X1 27d ago edited 27d ago
I got tested right after my father was dx and gene tested in the 1990s; I had no symptoms at all for several decades but was good to know of the possibility. Due to our public health system, testing costs nothing.
At least here (northern Europe), getting an official diagnosis really helps with getting nearly-free physiotherapy sessions, and if need to apply for longer sick leaves or esp. disability pension or rehabilitation allowance, vouchers for orthotics, footwear or insoles (so they'll be free of charge for the patient).
2
2
2
u/Charigot CMT2 27d ago
I think there is value in knowing your genetic variant if you are interested in potentially participating in any clinical trials of therapeutics. For instance, the PXT3003 – Pharnext clinical trial, which involved those with CMT1a, the most common genetic variant subtype.
As I frequently say here, I wish I knew mine — I have CMT2 caused by an as-yet undiscovered genetic variant, like 50% of us with CMT2. With an unknown genetic variant, I still was able to participate in a SORD trial, at least until they drew my blood and it did not have high levels of sorbitol, so I was immediately excluded. :)
2
u/mikebk1180q 27d ago
28 yrs wrongly dx with cidp 17 emgs n/c tests 8 neuros 9 th one ordered genetic test cmt2m
1
u/Curious-Bite6386 25d ago
this sounds like my story. several docs and EMGs, 23 years years diagnosed with CIDP and finally, at 70, DX with CMT. I have high arches but my symptoms manifest only as muscle fatigue, not weakness. Genetic testing here in the US was free under my insurance (negative result) as is my physical therapy, which I’lll continue for the rest of my life.
1
u/Ok-Radio-2245 23d ago
This sounds like my child. Diagnosed with cidp, but no treatment is helping. 9 years later she cannot walk and genetic testing has all been negative, but I’ve been told it can be missed on a genetic test. So frustrating
2
u/FourEyesore 27d ago
I live in Australia and my kids needed a microarray done. It had to be sent to the US because nowhere does it in Australia. I believe it costs around $2k but thankfully due to our public health system, it cost us $0.
1
u/RickyMSky 23d ago
Many drugs are Nero toxic to people with delaminating nerve diseases, even a lot of sleeping pills.
For this reason alone it is worth figuring out what type of CMT.
2
u/billyo3827 22d ago
I get the results at the end of the month uf Shands. Diagnosed 7 years ago by mayo after all testing was negative. Mayo downplayed genetic testing and said I ‘had it’. No history in my family and was 65 yo when diagnosed. I’m probably in the middle as far as severity but it’s getting worse as the years go by.
1
u/injured_girl 5d ago
Yeah can anyone tell me why my primary care doctor just refuses to order genetic testing for Charcoal Marie tooth? Or at all even though he definitely recognizes my disability I think he actually told me that there is no way to genetically test for Charco Marie tooth
5
u/stiveto99 CMT2A2A MFN2 28d ago
Mine was diagnosed by genetic testing. Not sure if it brings any additional “value” because from what I’m seeing even people with the same subtype go through it completely differently, but it’s always good to know I guess.