Huh, I had no idea that things like CRISPR were on their way. I’ll have to keep my eye on it and see how things develop, because that really does open up a lot of possibilities.
There are also zinc-finger nucleases and TALENs which can produce similar results but they are both tricky and very expensive to use. There is also the problem of delivery that all of these systems have in common.
The first CRISPR papers are only something like five years old, and it’s only been in the last, oh, two years or so that it’s taken off in model systems.
TALENs are a bit older, and, in my personal view, a more impressive accomplishment, but I think CRISPR is going to make them largely obsolete.
There are also things you can do to block the genes if you know what they are. For example RNAi, mentioned above can block a gene from coding into RNA, and thus effectively prevent all activities from that gene.
There are also other ways to block path ways of a given defective gene. Most biological processes are the result of a complex interaction of a bunch of genes that turn each other on and off. If you can throwsomethingin that blocks one piece of this network you might be able to shut down the whole process.
To be overly nitpicky, technically, RNAi doesn’t prevent transcription from DNA into RNA; it just destroys the RNA before it can be translated into protein.
One other thing to keep in mind with RNAi, which can be a benefit or a problem depending on the situation, is that it’s temporary. When you remove the RNAi hairpin, the cell goes back to normal. Also, RNAi knockdown is almost never complete. You’re nearly always going to have some residual level of gene expression that gets through. Again, that may or may not be a problem.
What good is gene therapy to know you have a 70% getting disease xx. It not like they can do any thing to change that. They cannot change you therapy with know how and technology.
Saying you have a 80% chance of getting dementia or caner does not change any thing.
Hollywood movies make it sound it so easy and that not how it works in the real world.
It depends on the disease. For some things, gene therapy could absolutely prevent you from having problems (at least in theory). Cystic fibrosis is the classic example.
Suppose some particular genetic test can tell you that you have a, say, 70% chance of getting disease xx whereas normal folks have, say, a 2% chance.
Given that info, you may be able to change something else to alter your outcomes. e.g. if you knew at age 20 that you were at high risk for diabetes at age 40 if you ever got fat or OD’ed on starchy carbs for a few years, you could alter your behavior now, rather than discovering too late that you’d fried your pancreas.
Some folks get mastectomies based solely on family history and learning they drew the short straw on breast cancer genetics too.
You’re right there certainly are circumstances where the additional knowledge can’t really be used to alter the course of the disease you’ll probably get, nor the likelihood of getting it. But you can use it to alter the course of your life up to that point. Which is definitely a two-edged sword.
Oh, yeah, testing alone is super useful for some diseases. Hereditary hemochromatosis is a disease that normally doesn’t manifest itself until late middle age - 40s or 50s or later. Up until then there’s not a symptom to be seen. But, sadly, the first symptom is usually irreversible liver damage or cancer of the liver or heart.
However, if you know you have the mutation that causes the disease, treatment is ludicrously simple: bloodletting. Just avoid iron in your diet and donate blood every now and then if your iron levels are getting to high, and you will never ever have a problem.
So either a completely normal, healthy life, or dying early of cancer. One genetic test makes the difference.
That depends on how you define “symptom”. It’s easily detectable, even short of a genetic test, through a very simple blood test which can be done in a routine physical. But yeah, you won’t feel it.
But on the larger topic, even if there’s no medical treatment at all, knowing about a disease will still help with things like financial planning.
Yes - “symptom” meaning “high levels of iron in the blood” shows up sooner. I was thinking more “symptom” meaning “huh - something’s wrong with me. I should see a doctor.”
Nitpick: The patient’s marrow is not removed, rather all or almost all of the marrow cells are killed via chemotherapy and/or radiation therapy as preparation before the transplant to get the patient ready to receive the donated cells.
That allows the donated cells to set up shop in the marrow, crowd out any of the patient’s remaining defective marrow cells (the ones causing the leukemia, for example) and produce healthy white blood cells, red blood cells, and platelets (and not just white blood cells, as other posters have implied).
And yes, these blood cells will have donor DNA, if the procedure works as intended. Except for the red blood cells, which don’t have DNA.
I’m pretty sure that Turble is hearing from his brother’s doctor that 97% of his brother’s marrow has his DNA, and not his whole body.
A guy that I work with is doing some data analysis for a gene therapy that appears to be curing one form of the “bubble boy” disease. Here is one article about it. A relevant quote from the article: