5 ms·

In color blindness, the cone cells produce an incorrect opsin protein that isn't sensitive to red (or is sensitive to a frequency close to green). Gene therapy

by ggreer 2y ago

In color blindness, the cone cells produce an incorrect opsin protein that isn't sensitive to red (or is sensitive to a frequency close to green). Gene therapy would fix that, though it'd probably take a while for the brain to understand the new information. The main reason this therapy isn't available is because the FDA has decided that the risks of gene therapy aren't worth the benefit of curing color blindness. I agree with that evaluation, but I also think mavericks should be allowed to try curing their own colorblindness (assuming they had informed consent and paid for the therapy themselves).

trebligdivad 2y ago
The 'though it'd probably take a while for the brain to understand the new information' is an interesting question; on one hand people say you need to fix stuff early in development while the brain is still very plastic (so great for this kid); but then again there is that demo of people getting used to vertically flipped vision with weird glasses; so perhaps something is flexible?
- adgjlsfhk1 2y ago
  yeah I'd be pretty surprised if your brain didn't figure it out in a week.
- wizzwizz4 2y ago
  The brain is good at re-mapping things where it can make a distinction, but it seems to only learn distinctions in so-called "critical periods". See doi:10.1038/228477a0 for a famous 1970s experiment on the subject.
  - lupire 2y ago
    There are lots of examples. Phonemes for language and are a very common example of things that can't be learned easily or at all later in life. But huge changes like a major color might overcome that. Humans learn to recognize new major objects they've never seen before.
    - wizzwizz4 2y ago
      Humans can learn to recognise new sensory modalities, too (see paragraph 4 of doi:10.3389/fnhum.2019.00443's introduction) – but only if there's hardware that responds to them. The question is whether the visual cortex is capable of making the distinctions. If colourblindness glasses (e.g. EnChroma®) work for you, then I suppose the answer is trivially "yes, because it already does" – and we should expect gene therapy to be useful. If there are people for whom those glasses don't do anything at all, I'd be more cautious.
derefr 2y ago
> I agree with that evaluation, but I also think mavericks should be allowed to try curing their own colorblindness (assuming they had informed consent and paid for the therapy themselves). I mean, what's stopping you? This guy cured his own lactose intolerance: https://www.youtube.com/watch?v=J3FcbFqSoQY https://www.youtube.com/watch?v=J3FcbFqSoQY But I'm guessing — in part because you say "paid for the therapy" — that you don't really mean "should be allowed to cure their own colorblindness"; but rather "should be allowed to buy a colorblindness treatment from a vendor of such" or maybe "should be allowed to request a prescription of a colorblindness treatment from a doctor who acquires it from a vendor of such." And you're already also allowed to do that — in theory. The FDA doesn't care about people buying medical treatments. It cares about companies selling them. Because companies are profit-focused, and the quickest way to money in medicine is to lie. For you to be able to get what you want, there'd have to be an intermediate category that stops just shy of the current "FDA-approved medical therapy" category. For a treatment to qualify for this category, it would still have to pass both safety and efficacy studies. The only thing that would be different, is that the FDA wouldn't weigh the safety vs. the efficacy of the treatment at the end; but instead just put an absolute minimum threshold on both safety and efficacy, and leave the prescriber to determine whether the safety risk outweighs the efficacy. But think about that word "prescriber." This would certainly allow people motivated to do this to go to their doctors and ask for such treatments specifically. But it would also enable doctors to choose such therapies for their patients, without the patient being previously aware of the treatment option. And doctors can be bought. (See: doctors prescribing on-patent drugs when equally-effective generics are available; doctors adding on unnecessary adjunct therapies because a sales rep convinced them they should "give it a try"; etc.) Do you want to live in a world where there's no ability for regulatory bodies to set a safety:efficacy-ratio threshold on a doctor's ability to prescribe drugs to patients? A world where a (bad) doctor might prescribe a drug that has a huge risk for very little chance of success, and all they have to do is put a consent form in front of the patient for the huge risk — without even having to explain the low-efficacy part? (Honest question. Some people might very well prefer such a world.)
- deleted 2y ago
  [deleted]
- 2y ago
scottlamb 2y ago
> The main reason this therapy isn't available is because the FDA has decided that the risks of gene therapy aren't worth the benefit of curing color blindness. I agree with that evaluation, but I also think mavericks should be allowed to try curing their own colorblindness (assuming they had informed consent and paid for the therapy themselves). In what way do you agree with that evaluation then? The FDA certainly doesn't force anyone to undergo a treatment. And my understanding was the FDA doesn't decide who pays for a given treatment. In particular I don't think they define what medical insurance companies (or Medicare/Medicaid) have to pay for, do they? I think they just say whether the treatment is ethical to be performed at all. So when you say that mavericks should be allowed to try it, I think you're simply disagreeing with them?
Ballu 2y ago
Could you provide the ref/details of this particular gene therapy and FDA views? I can understand why the FDA wants to move ahead slowly unless the condition is life-threatening or the impact is life-changing.

by ggreer 2y ago

trebligdivad 2y ago

The 'though it'd probably take a while for the brain to understand the new information' is an interesting question; on one hand people say you need to fix stuff early in development while the brain is still very plastic (so great for this kid); but then again there is that demo of people getting used to vertically flipped vision with weird glasses; so perhaps something is flexible?

adgjlsfhk1 2y ago
yeah I'd be pretty surprised if your brain didn't figure it out in a week.
wizzwizz4 2y ago
The brain is good at re-mapping things where it can make a distinction, but it seems to only learn distinctions in so-called "critical periods". See doi:10.1038/228477a0 for a famous 1970s experiment on the subject.
- lupire 2y ago
  There are lots of examples. Phonemes for language and are a very common example of things that can't be learned easily or at all later in life. But huge changes like a major color might overcome that. Humans learn to recognize new major objects they've never seen before.
  - wizzwizz4 2y ago
    Humans can learn to recognise new sensory modalities, too (see paragraph 4 of doi:10.3389/fnhum.2019.00443's introduction) – but only if there's hardware that responds to them. The question is whether the visual cortex is capable of making the distinctions. If colourblindness glasses (e.g. EnChroma®) work for you, then I suppose the answer is trivially "yes, because it already does" – and we should expect gene therapy to be useful. If there are people for whom those glasses don't do anything at all, I'd be more cautious.

derefr 2y ago

> I agree with that evaluation, but I also think mavericks should be allowed to try curing their own colorblindness (assuming they had informed consent and paid for the therapy themselves). I mean, what's stopping you? This guy cured his own lactose intolerance: https://www.youtube.com/watch?v=J3FcbFqSoQY https://www.youtube.com/watch?v=J3FcbFqSoQY But I'm guessing — in part because you say "paid for the therapy" — that you don't really mean "should be allowed to cure their own colorblindness"; but rather "should be allowed to buy a colorblindness treatment from a vendor of such" or maybe "should be allowed to request a prescription of a colorblindness treatment from a doctor who acquires it from a vendor of such." And you're already also allowed to do that — in theory. The FDA doesn't care about people buying medical treatments. It cares about companies selling them. Because companies are profit-focused, and the quickest way to money in medicine is to lie. For you to be able to get what you want, there'd have to be an intermediate category that stops just shy of the current "FDA-approved medical therapy" category. For a treatment to qualify for this category, it would still have to pass both safety and efficacy studies. The only thing that would be different, is that the FDA wouldn't weigh the safety vs. the efficacy of the treatment at the end; but instead just put an absolute minimum threshold on both safety and efficacy, and leave the prescriber to determine whether the safety risk outweighs the efficacy. But think about that word "prescriber." This would certainly allow people motivated to do this to go to their doctors and ask for such treatments specifically. But it would also enable doctors to choose such therapies for their patients, without the patient being previously aware of the treatment option. And doctors can be bought. (See: doctors prescribing on-patent drugs when equally-effective generics are available; doctors adding on unnecessary adjunct therapies because a sales rep convinced them they should "give it a try"; etc.) Do you want to live in a world where there's no ability for regulatory bodies to set a safety:efficacy-ratio threshold on a doctor's ability to prescribe drugs to patients? A world where a (bad) doctor might prescribe a drug that has a huge risk for very little chance of success, and all they have to do is put a consent form in front of the patient for the huge risk — without even having to explain the low-efficacy part? (Honest question. Some people might very well prefer such a world.)

deleted 2y ago
[deleted]
2y ago

scottlamb 2y ago

> The main reason this therapy isn't available is because the FDA has decided that the risks of gene therapy aren't worth the benefit of curing color blindness. I agree with that evaluation, but I also think mavericks should be allowed to try curing their own colorblindness (assuming they had informed consent and paid for the therapy themselves). In what way do you agree with that evaluation then? The FDA certainly doesn't force anyone to undergo a treatment. And my understanding was the FDA doesn't decide who pays for a given treatment. In particular I don't think they define what medical insurance companies (or Medicare/Medicaid) have to pay for, do they? I think they just say whether the treatment is ethical to be performed at all. So when you say that mavericks should be allowed to try it, I think you're simply disagreeing with them?

Ballu 2y ago

Could you provide the ref/details of this particular gene therapy and FDA views? I can understand why the FDA wants to move ahead slowly unless the condition is life-threatening or the impact is life-changing.