Reply #34: It does have negative implications though. [View All]

[Xithras]

CCR5 evolved to fight specific types of infections, and while the absence of that gene does block HIV, it also impairs immunity to the types of diseases CCR5 would help fight in other people. People with a CCR5 knockout are at a much higher risk of death from West Nile, as an example.

That said, I'd bet that most HIV patients would gladly trade a known killer for one that simply poses a "statistically significant" chance of killing them.

By the way, the link between the CCR5 mutation and the Plague has been largely disproven. The mutation has been detected in examinations of European remains predating the Black Death, and is probably a holdover from another disease that happened in prehistoric times (plagues have been around as long as we have).