What ends up happening is that your DNA is made of a bunch of things called bases, which are four different chemicals, represented by the letters A, T, C, and G. The different combinations that these four chemicals make in the DNA can make the INCREDIBLE variation among the people, animals, plants, and every living thing of the ENTIRE WORLD! It’s really, really, amazing how it works… and it makes you wonder how it all comes about. Those are subjects for other blogs though ;)
Anyway, in Huntington’s, the DNA has a problem with repeats – normally, DNA has a bunch of repeat sequences (like AGAGAGAG), and it’s supposed to, but there are some places where you’re not really supposed to have repeats, and those are the repeats that mess things up. Actually, normal people have these repeats too, the people with Huntington’s just have a lot more of them – it’s something like normal people have 19-21 repeats of the bases CAG (in that order) and people with Huntington’s have around 46. Also, the more repeats one has, the worse the effects of Huntington’s are. I still have to put together my stuff on the effects of Huntington’s, so I’ll have that later.
So the cause is more repeats. Why would more repeats be bad, though? That’s the question I asked. The answer, as it turns out, is protein. “Don’t I eat enough protein? That doesn’t make any sense!” Nope. That’s not the problem. Basically, there are a TON of different proteins floating around, doing different jobs in your body. In order for things to happen in the body (hair, skin, nails, everything to get made, as well as all sorts of important things happening with chemical balance and reactions), all different sorts of proteins have to be made. This happens involving the DNA. The bases on the DNA are read, and through a couple of processes called transcription and translation, are turned into chains of amino acids. Amino acids are basically the building blocks for proteins. They’re a lot more complicated than that, but if you want to find out more, check out the Wikipedia article. The chains (also called polypeptides, because an amino acid is called a peptide) are the same things as proteins, just with a different name. Have I confused you yet? I took one look at the overview (not even the actual text) for transcription and translation and my head started spinning, so I think I have you beat. Anyway, so amino acid = peptide, protein = polypeptide.
What happens in transcription is that the DNA is read and turned into a sort of half-DNA called RNA, which is usually single-stranded (ergo, half-DNA) but the real difference is some sugar in the backbone. Nothing too big for non-scientific types. This RNA (specifically, mRNA) is then read again to create the amino acid chain. Now, the thing that messes people with Huntington’s up is the fact that they have more of these repeats, so they have longer amino acid chains, which messes up the structure of the protein. Scientists don’t know what the protein (interestingly enough, called Huntingtin, that’s right, HuntingtIn) does yet, so they can’t really pinpoint the real cause, other than the fact that the DNA repeats mess up the amino acid sequence of the protein.
So basically that’s all it is. Repeats in my DNA can doom me to an early and ugly death, but the worst part is, I can pass it on. The problem is I didn’t really find out a lot about how it gets passed on, or its effects. I’m wayyy too tired to do anything more right now, so I think I’m going to go to sleep. However, you can rest assured that I’m going to find out as much about this as I can and, you know, put it out there for the world to see as I try and puzzle my way through it.
