Chinese medicine FTW ☯

*learn something new today

Adding video to channels (Learn) - requested by eric3579.

Interesting. I've got a semi-relevant story, but I get long winded so feel free to skip to the next comments if you like.

My wife (Thai) and I (American) had our first daughter this year. When she first got pregnant, one of the doc's first priorities was to get us both tested for "Thalassemia", which I had never heard of before. Apparently it is a blood disorder that affects hemoglobin production and therefore red blood cells -- if both parents carry the (rather rare) recessive gene, it can be a pretty bad deal.

It turned out that my wife is in the 1% or so of Thais that carry the gene (but she doesn't express / suffer from it, it is recessive and she has the dominant gene also). I had to get tested as well, but they said it would be incredibly unlikely that I'd be positive and I wasn't. So, our daughter has a 25% chance of being a carrier like my wife but zero chance of suffering from the effects of it.

Anyway, I was curious about the disease and asked the doc why it is a big deal here (every pregnant couple MUST get screened for it here when getting hospital/prenatal care) but I'd never even heard of it in the US. It turns out that the disease / genetic mutation arose only in places with high rates of malaria. As it happens, the genetic effect on your blood cells that the mutation has makes you more resistant to malaria -- full-on exhibitors of it (two recessive genes) are far less likely to die of malaria than people that don't have the gene. That is, assuming that you don't have the extreme variants of it that make it very unlikely to survive early childhood. Basically, if you have the disease and yet are healthy enough to survive to adulthood, you're close to malaria immune (that's overstating it, but ballpark). The malaria parasite can't survive and reproduce properly on your funky Thalassemia-affected red blood cells.

I thought that was a pretty interesting evolutionary response that must have arisen from some populations being pretty much decimated by malaria back in pre-recorded history. Current carriers like my wife are probably the descendants of lucky folks that survived a deadly outbreak in history by virtue of having a disease/mutation that is, under normal circumstances, slightly or even extremely bad in species survival / reproductive fitness terms. I thought that was kinda cool -- but I'm glad that neither my wife nor my daughter are/can be full-on expressors of the gene.

Sickle-Cell Anemia is similar with a slight twist. The disease is caused by a mutation of a gene for haemoglobin, which deforms and causes the red blood cells to take on a sickle shape. In the case of SCA the gene has more than one dominant allele, known as codominance (I think thats also why hair colours "mix", but dont quote me on that). As a result carriers of the disease have one copy of the mutated gene and one healthy copy. They produce healthy AND deformed sickle shaped red blood cells. Carriers with this heterozygous form are practically free from symptons of the full disease and while not immune to malaria they are more resistant. Strangely, and for reasons I dont fully understand, those with the full disease are still vulnerable to Malaria, or at least malaria makes the symptoms of SCA worse.

Unsurprisingly SCA is fairly common in parts of Africa where Malaria claims a lot of lives. It would be a pretty amazing adaption if it were not for the 25% chance that any child between two carriers suffered from the full disease.

Now for my somewhat related story:
I tried the "natural" Malaria remedy in Kenya. The Masai guide had this huge grin on his face when he offered it to me that in hindsight should have definitely tipped me off. I'm guessing it was quinene based because it was so bitter that I wretched it and a fair portion of my breakfast up and out on the spot. He made it up later when he found some wild honey (you know, as you do - Masai ftw) to take the taste away.

@Jinx - Cool -- I knew Thalassemia and Sickle Cell Anemia were similar, but I didn't know SCA granted similar malaria protection. Probably both are evolutionary responses to the disease (although "response" makes it sound like there was a conscious agent responsible).

I went to Africa with my folks when I was 4-5 years old. We all took quinine for the malaria protection, but it must have been pre-mixed with stuff to take the bitter edge off of it, like the honey did for yours. But I guess at 4-5 years old I still thought it was pretty suspect tasting -- my folks ended up telling me that it was "zebra milk" in order to get me to choke it down.