[rdb3]

We get Sickle Cell Anemia more than other ethnic groups. I don't know if that's the same thing, though.

[tortoise]

We get Sickle Cell Anemia more than other ethnic groups. I don't know if that's the same thing, though.

That is a hereditary disease, not infectious. However, the mutation that causes it does grant an ethnicity specific immunity/resistance to malaria. There are a number of ethnicity specific hereditary diseases that confer protection from other diseases that are bad for the host if they get the genes from both parents, but beneficial if they get it from only one.

Another example of this is Tay-Sachs hereditary disease common to eastern European Ashkenazi Jews. A single copy of that mutation will give immunity against TB, but two copies will kill you.

Many other hereditary mutations that protect against infectious disease cause no hereditary diseases on their own, but they are less well-known primarily because there is no nasty side-effects to highlight the existence of an interesting mutation. Hereditary diseases like Sickle Cell Anemia would normally be bred out of a population if it was not for the fact that at some point the mutation also greatly enhanced survivability of the person carrying it.

[null and void]

We get Sickle Cell Anemia more than other ethnic groups. I don't know if that's the same thing, though.

Nope that's a genetic disease.

Having two Sickle Cell genes equals Sickle Cell Anemia.

Having one Sickle Cell gene equals near immunity to malaria, a very handy thing for a sub-sahara african!