Does the non-mutated CCR5 gene do anything important that the mutation disrupts? (In the sort of way the mutation for malaria resistance causes sickle cell anemia if you have two of them.)

"HIV infection if untreated by anti-virals, leads almost inevitably to the diagnosable disease AIDS"

I'm basically agnostic on the HIV/AIDS question, but my layman's understanding is that even mainstream thought on AIDS would not support this second statement. I believe it's well understood that there are nontrivial numbers of people who are HIV+ and do not develop AIDS, decades after infection. This may be the gene mutation(s) referred to by timtyler, or it may be something else (I'm not well-read on the specifics)

First I should point out that even the mainstream, as far as I understand, does not claim that HIV-1 is the sole cause of AIDS, unless one takes AIDS to be a very specific form of immune suppression only caused by HIV, but so far there is little scientific support for that - other causitive factors can mimic AIDS-like immune supression, and I believe this knowledge and view is mainstream.

As to your 2nd point, kodos96 addresses that, and again it's not even the mainstream position.

So first off, I am not disputing what you are claiming - firstly because it's not even the mainstream position, but secondly because what I am disputing is something of a meta nature. I am disputing the certainty in the mainstream position.

I hold a range of beliefs about HIV and AIDS, and distribute probabilities amongst them. I naturally tend to simultaneously consider multiple viewpoints. In this case they are:

1. (orthodox) HIV is the prime cause of a progressive immune deregulation, although riskgroup specific co-factors contribute

2. (moderate) HIV, like the other exogenous retroviruses, has health negative effects, but is hardly outright lethal. It exists in an evolutionary limbo - it was once more lethal, but is evolving into more of a harmless vertically transmitted symbiote. Other exogenous retroviruses have been implicated in cancers, but not strongly. They are somewhere between epidemic viruses and harmless exogenous retroviruses that long ago were neutered and intergrated into our DNA. Furthemore, there are several genetic variations, and they have differential individual effect - picking up novel retroviruses from someone else's blood is not good for one's health. .. .

3. Deusberg's fully harmless passenger retrovirus theory.

I assign highest creedence to 2 atm. Note that it is very difficult to distinguish between these 3 theories. About the only specific differentiator would be koch's postulate - isolating the virus and then infecting it into new hosts, observing the symptoms, and then reisolating the virus from infected cells. HIV has not been shown to cause AIDS under that criteria - it fails in any animal models.