Like Non-Cancer terminal illness that can affect young (age 10-13) girls?, I have a major girl that needs to have a likely-terminal, repeatedly hospitalized, disease, but has a healthy sister. And it needs to still be deadly even if it appears in a world with effective and quick genetic engineering tech.

I was going to advance all medical tech, but that's a bit too difficult, so I'm sticking to just the genetic sciences.

It being uncaught by any screening, and only treatable by new genetic engineering tech in the final years (story start time) of her previously expected lifespan, so a "miracle cure" plot would be fine.

The leading answers in the question that inspired mine, were...

  1. Duchenne Muscular Dystrophy
  2. Congenital heart disease
  3. Cystic fibrosis
  4. Juvenile Tay–Sachs disease
  5. Rett Complex

I suppose only "Congenital Heart Disease" would be the hardest to cure even with Current Med / Gene Tech +5 Years. But are there more?

  • $\begingroup$ Does this need to be 100% medically accurate? Most of the readers would probably not care, and don't have medical expertise anyway. Professional medics are already used to chuckling at fictional medical conditions. Besides, conditions with no clear root cause do exist in the real world. $\endgroup$
    – void_ptr
    Commented Dec 20, 2020 at 2:16
  • $\begingroup$ @void_ptr - Oh, the "No Clear Root Cause" would be good. Especially since I do need a healthy sister. I'd take that answer. $\endgroup$
    – Malady
    Commented Dec 20, 2020 at 2:19
  • 1
    $\begingroup$ How is this different from the linked prior question? It looks the same to me. $\endgroup$
    – Willk
    Commented Dec 20, 2020 at 2:28
  • $\begingroup$ @Willk - Can't have anything that can be cured with genetic engineering, basically. $\endgroup$
    – Malady
    Commented Dec 20, 2020 at 2:45
  • $\begingroup$ There's no miracle cures for any of the listed diseases in the other essentially identical query. Genetic engineering is one of those promising technologies that's "on the way", but is nowhere close a five year time frame. So none of those conditions are going to be magically cured that way either. Hence the question: how is this fundamentally different? $\endgroup$
    – elemtilas
    Commented Dec 20, 2020 at 19:54

2 Answers 2


Prion diseases.

They are mostly acquired but can also be genetic in origin so you can choose whatever fits your story. They are rare, difficult to detect, and slow-acting.

I imagine they are difficult to treat even with genetic therapy because once those prions run loose and self-replicate, they are there even if you gene therapy the genetic flaw away. Simply replacing bad genes with healthy ones grabbed from someone else isn't going to cut it here.

You can't genetically engineer away a foreign self-replicating substance already in your body short of making mechanisms to select and filter it out, and with prions being unrelated to both virii and bacteria and without pre-existing mechanisms (as far as I know) to modify or augment you need to cook up something from scratch. That's tough and far beyond what we see in movies like GATTACA (then again they also don't seem to even try and treat people with weak hearts so maybe they are just good at diagnosis and not treatment).

My understanding is that the misfolded proteins are more stable so you can't even design a new protein to go around unfolding them the same way they became misfolded to begin with, or at least it is more difficult to go one way than the other. You're going probably to need to be custom designing proteins or antibodies to treat any advanced form of prion disease which is a step above what most people think of when they think of genetic engineering.

I feel this starts wading into high-level molecular engineering. There's genetic engineering which lets you do whatever you want with DNA, but then there's advanced molecular engineering which lets you do stuff like make silicon base lifeforms with their own version DNA. Basically nanotech advanced enough to let you design and produce molecular machinery which is what proteins are.

Apparently the immune system can't just hunt them down either, because they technically aren't foreign bodies. It seems like the immune system might actually help them spread.


  • $\begingroup$ Slow-acting so she can be effectively constantly hospitalized? This fits my requirements... $\endgroup$
    – Malady
    Commented Dec 20, 2020 at 3:39
  • $\begingroup$ @Malady Yes. The reason it's resistant to gene therapy is not because it progresses too fast to develop and administer a gene therapy. $\endgroup$
    – DKNguyen
    Commented Dec 20, 2020 at 3:42
  • $\begingroup$ Thinking on how to choose between this and the other answer... Is this more lethal? Or since it's got a genetic basis, it's more likely than endometriosis, to be shared with a sister? $\endgroup$
    – Malady
    Commented Dec 21, 2020 at 5:06
  • $\begingroup$ @Malady Prions don't need a genetic basis. You can get it by eating the wrong thing. See the second sentence of my answer. $\endgroup$
    – DKNguyen
    Commented Dec 21, 2020 at 15:33
  • $\begingroup$ Oh. Right. Mad Cow. $\endgroup$
    – Malady
    Commented Dec 21, 2020 at 15:33

Rather than find an obscure medicial condition which exactly matches your timeframe and difficulty to cure, may I suggest finding a common cause of death or injury for that age bracket and adding complications?

The Leading causes of death in that age group is "Land transport accidents", with it becoming "suicide" at age 14.

How about complications from one of those? Damage to a critical organ from a car crash or past suicide attempt which is threatening to fail and cause death at any moment.

Her attempt at poisoning herself could've destroyed her kidneys or liver. She could have major blood vessels juryrigged back together after a major car crash. She could have lost heart or lung performance, making her more susceptible to disease, etc.

If you want a commom disease which cripples 13 year old girls but medical professionals get stumped with every time, I'd suggest Endometriosis. Your character will be screaming in pain in the fetal position 5 days in 28 and all the doctors will be giving for it is paracetamol and pregnancy tests. Average time from symptoms appearing to diagnosis is 7.5 years, I've personally known a case that took 12 years. 12 years of "oh it's just period pain you'll be right", 12 years of her passing out in emergency department waiting rooms only to be sent home with chemist-grade (pharmaceutical, for you yanks) painkillers.

In that time all sorts of other things are mistakenly considered, some of which could be deadly.

Complications from endometriosis could theoretically be deadly - blood appearing in places it shouldn't can cause secondary problems.

  • $\begingroup$ Her attempt at poisoning herself means she might try again. Depression is why people commit suicide, and there is no prospect of genetic engineering fixing that. If the character can be depressed and still fulfill her role in the story that would fit the bill. $\endgroup$
    – Willk
    Commented Dec 20, 2020 at 3:05
  • $\begingroup$ I was thinking this wouldn't fit "repeated hospitalized", but I blanked on 5/28 days monthly. This is a good answer! Might be the winner. Dunno yet. $\endgroup$
    – Malady
    Commented Dec 20, 2020 at 3:38

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .