SMA News Forums Forums Diagnosis​ Info ​and​ ​General​ ​Questions SMA Typing (as in type 1, 2, 3 or 4)

  • SMA Typing (as in type 1, 2, 3 or 4)

    Posted by deann-r on October 21, 2021 at 8:00 am

    Years ago, for a brief moment, it was noted in my chart I had SMA type 3. The doctor claimed I’d “be dead by now” if I had type 2. Ever since the whole typing system seems faulty to me. On one hand, if I did have type 3 maybe I’d have a better prognosis. On the other hand, it would make getting the things I need more difficult.

    For some reason, type 2 seems to be the sweet spot when it comes to insurance. Luckily for me, that type 3 notation was quickly buried by my neurologist and more knowledgeable doctors. I feel like need should take precedence over type though. Unfortunately, insurance doesn’t always see it that way. Often individuals with type 3 struggle to get coverage for items that would benefit them. If you’re type 1 sometimes your SMA is considered too advanced to benefit from certain things which is completely bogus. It’s easy for parents to focus on type as well when their attention should be on supporting their child regardless of ability.

    I want to stress not to get hung up on SMA typing. As treatments emerge the SMA type system is evolving. I don’t think anyone can say if someone is a certain type they can or can’t do x y z definitively. There’s almost always an anomaly. So basing type on ability isn’t the best gauge. Basing it on SMN 2 copies isn’t reliable either because the quality of those copies makes a difference. I like to think of SMA as a spectrum. If that’s the case type 2 is smack dab in the middle. Where function is concerned a “strong” type 2 would have more abilities and a “weak” type 2 would have less function. Maybe your type would change throughout your lifetime. Just a thought. Of course with treatments, it’s a whole different ballgame. Frankly, I’d like to see the typing system thrown out the window.

    Have you run into issues with being a certain SMA type? How would you like to see the classifications evolve?

    alyssa-silva replied 2 years, 8 months ago 7 Members · 7 Replies
  • 7 Replies
  • lupa-f

    October 21, 2021 at 10:23 am

    I’m pretty close to a textbook type 3. I only started having very slight symptoms when I was about 6 or 7 and I walked unassisted until I went to college at 18. I haven’t had any real issues as an adult with insurance because of being type 3. I’ve just had the usual stuff where they tried to deny Spinraza because of age and my wheelchair because of paperwork mishaps, but the reason wasn’t because of the type. I know some insurances were trying to limit Spinraza on type/age at first, but since Medicare/Medicaid allowed it for everyone I think almost all of them relented on that.

    My mom did have a lot of trouble getting my first scooter covered when I went to college, but I wasn’t involved with that so I don’t know what happened there. I also hadn’t been diagnosed with SMA yet then either, so it couldn’t have been about the type.

    I think the types are still pretty useful as long as they’re not considered too rigidly. It seems like most here are type 2s and my experience with SMA is pretty different from them. I’ve never had scoliosis or rods in my spine, I don’t have caregivers, I live on my own and drive my own car. And then mentally it seems like those who’ve had SMA affect them from very early on consider it a part of themselves whereas I consider it something that happened to me, I don’t consider it part of my identity since it wasn’t something that was always there really (I know technically it was, but you know what I mean).

  • delphine-andrews

    October 21, 2021 at 11:45 am

    I was told I was a 2.5, whatever the means. It is so arbitrary. It just goes to show that there are some things even the “experts” don’t know even if they try to classify it.

  • dennis-turner

    October 21, 2021 at 12:17 pm

    From what little I hear, typing is becoming less effective. I am type 3 but I have very late onset, mid teens before I was actually tested and diagnosed. Walked until I was 55, but around that time started to lose strength fast. By some measures that would make me type 4ish.

    I look at these sweet little ones who have been treated with the gene therapy and have hope that this disease can be put behind us.

    • lupa-f

      October 21, 2021 at 12:58 pm

      Yep, that’s one thing that’ll blur the lines between types even more. Children that are getting treatments are reaching milestones they never would have and the typical type 1 or 2 progression doesn’t exist for them any more.

  • tammy

    October 21, 2021 at 12:46 pm

    I fully agree. I don’t think typing should have any factor in insurance coverage. It should be what your needs and limitations are. My mom was told the same thing about me when I was a baby and classified as type 2, that I probably wouldn’t live past 2 years old. Here I am 40 years old and I’m one of the healthiest sma patients that I know personally. Later on as I got to elementary school age I met the most wonderful orthopedic doctor I’ve ever had. He was my doctor from childhood all the way up until he retired last year. He always said that even though I’m classified as a type II I don’t really fit into the category because of my upper trunk control and head control, and the fact that I’m able to swallow and have no problem eating any kind of food no matter the texture or hardness. He basically used the phrase we all know is that I’m a strong type 2. I’m also pretty healthy in the lung department and can clear my mucus. Of course when I’m sick sometimes it’s a little harder but for the most part I can get everything up with no issues. Also something they said is that it’s very strange because my lung function has actually improved with age lol. It was more difficult when I was younger. Now at my age I’m the healthiest I’ve ever been. Kind of makes no sense but I’m surely not complaining LOL. The only thing that has decreased starting in my mid 20’s was the strength in my arms and hands. I used to be able to lift my arms from my lap to my face. Which I can’t do anymore. And it’s extremely frustrating. But I guess I shouldn’t complain because it could be worse. I’m still able to feed myself though but I have to have my arms situated in a very specific position to do so which makes things difficult when you are out with friends or by yourself. But I find my ways around things for the most part

  • andrew

    October 21, 2021 at 5:36 pm

    I agree that the old SMA type system is super outdated and for me personally and has caused me issues. I was diagnosed with SMA type III when I was a child and the few years leading up to my growth spurt I struggled to walk independently and around the time of my growth spurt at age 12 is when I pretty much lost my ability to walk independently. Because I had the classification of type III a lot of my physical issues and inabilities were not addressed or helped with as much as they could have been (One big example is the fact that I was never physically able to use a public restroom since late elementary school but I never got help with that until after I turned 18 and qualified for the MA PCA program).


    In short the old type system provides almost no benefit in terms of predicting future outcomes for disease progression and in cases such as my own actually cause a lot of my issues as a child to be overlooked. The SMN2 copy number system I do think does a better job of predicting disease progression/severity then the old one which purely looks a phenotypical snapshot of functionality at childhood. But at the same time like you said the SMN2 copy system isn’t completely reliable either and has a lot of things that are less well understood that can still impact disease severity and progression. And it’s 100% true that thinking of SMA as a spectrum of severity that changes over time is the most accurate way to look at it but currently medicine can’t accurately track something like that so they can’t put that into practice.


    I agree that relying too much on any type of type system will probably lead to bad results. And every case of SMA should be monitored closely and on a case by case basis to address the physical needs of every individual. It’s always good if medicine continues to find more and more accurate markers that can predict disease severity/progression in order to plan for the needs of individual with SMA, especially in the case of youths with SMA who don’t have the same ability to communicate or plan for their future needs like adults can.

  • alyssa-silva

    October 22, 2021 at 10:51 am

    My medical records actually say type 1/2 because I’m sort of in-between the textbook diagnoses for both. But I agree that typing is becoming less effective now with treatments. I think even in general, though. Even with types, SMA presents so differently in everyone that I can’t see how much of a difference being classified under a certain type would make.

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