Transplantation of HSCs with a usually occurring C–C chemokine receptor type 5 mutation, also known as the CCR5 mutation, confers a noticeable loss of HIV-1, and production ablation of the CCR5 gene, which is a method of modifying DNA to disrupt the production of a specific gene, is a perfect treatment method for HIV-1 infections. The gene discussed is CCR5; the disease is HIV-1 infection.