I mean it seems to me that it is impossible to replace every cell’s DNA with “fixed” one no matter how advanced technology will we have…
So does someone with genetic illness have no hope of ever be cured?
One hope that’s currently being explored is gene silencing. This doesn’t remove the genetic issue, but it prevents the gene from being expressed.
Some gene are only expressed in certain cells, so you can then repair the genes in only the target cells. Also, sometimes you only need to fix a small percentage of the cells, because enough protein gets made for what the body needs.
For example, X-SCID which is an immune defect (bubble boy syndrome) was fixed by harvesting the bone marrow, introducing the working gene, and reintroducing it the patient. The bone marrow began making the proper immune cells. So, the entire body doesn’t need a gene fix, just the stem cells. Unfortunately some patients developed leukemia, so it is no longer being done that specific way.
I don’t know if reverse transcriptase to put the correct gene into cells is realistic anytime soon but if it is then that could be a treatment. With HIV when it integrates itself into your DNA it is carried down after your cells undergo mitosis. RNA interference can be used to silence the defective gene.
It depends hugely on what the disease is and what the biochemistry behind it is. Currently, we can’t cure any of them, but some cures are easier to imagine than others.
And gene unsilencing, an intervention enabling expression of protein from a gene copy normally silenced (compensating for flawed expression of protein from the gene copy normally active).
There is also antisense therapy, where the messenger RNA is blocked so that it can’t function. This would not be a cure though since one needs to continue taking the blocker.
And many genetic diseases can be cured surgically. Repairing defective body parts or removing a defective organ and replacing it with a healthy one for example.
Hereditary hemochromatosis is a genetic disease that can essentially be cured. I say essentially because although the underlying genetic defect cannot be fixed, a simple treatment can completely block development of disease and ensure a completely normal life for people with it. The treatment? “Theraputic phlebotomy” also known as bloodletting. One of the oldest medical treatments in history is still used for this condition.
Hemochromatosis is when you have too much iron in your blood. In the case of HH, it’s because your intestinal cells are being told, incorrectly, that your blood is iron deficient, so they’re taking up all the iron they can find. Over time, too much iron in the blood can react and cause all kinds of cancers and other nasty stuff. So, simple answer - just take out blood and with it, iron, to keep iron levels in check. Problem solved. The trick is figuring out who has the disease in the first place, as often, the first symptom is, you know, liver cancer, at which point it’s too late.
Is this a cure, or an ongoing treatment? If the blood has to be drawn periodically for the rest of your life, IMO it is not a “cure”.
Once you’re diagnosed, you have to do several blood, uh, donations, for lack of a better word, relatively quickly to get your iron levels back down to normal. Once you’re in a normal range, your doctor might check your blood perhaps every year or so and see if you need to have it drawn again. It’s no more onerous than going to your yearly blood drive, and many people don’t even need to go to that much trouble. Limiting iron intake in the diet is often sufficient. Just skip the occasional steak, and you’re good to go. As far as chronic illnesses go, this is a pretty awesome one to have, as long as you’re diagnosed before any permanent damage has been done.
I should also point out that even among those with the mutation(s), it’s primarily a male disease, because women naturally tend to lose a lot of blood, and therefore have a hard time building up dangerously high iron levels.