Sickle Cell Disease 360 Human Explorer Tour with Dr. Rob (Part 2)

Part 2

Now let’s look more closely at what happens in this situation. How do you get sickle cell? How can you avoid getting it? Or what does it mean when you do have it? In this situation, both the mother and father here are shown to have a sickle trait where one of their chromosomes has it and the rest don’t. If they were non-carriers, there would not be this gene there. If they had the disease, they’d have it in both sets of chromosomes.

So the mom and the dad have the trait, and there is a chance as you break up—this one goes here, this one goes there, and so on. As the mom and the dad each give one gene to each child, one child does not have the disease, one child has both and does have the disease, and the other two children have the carrier state, just like the parents. This does not mean that if you have four kids, one gets the disease every time. It means every single time you have a baby, there is a chance of no disease, a chance of the disease, and a chance of being a carrier.

Let’s look further at that. When you look at the genes, and they unravel from the chromosome inside the nucleus, it becomes chromatin. That chromatin creates a nucleosome, and often that nucleosome unwinds the double helix of DNA. In that DNA it looks pretty normal except for this mutation. What the DNA does is help make the proteins called hemoglobin. Enzymes work along the DNA with messenger RNA, making copies of the DNA and creating a protein. That protein is called hemoglobin.

There’s normal hemoglobin and there’s sickle hemoglobin. The interesting thing is that normal hemoglobin doesn’t have much polarity, like a magnet, but the sickle ones have positive and negative charges that attract each other. Look how they line up like a bunch of Legos.