CCR5 and AIDS: The larger block in 3p21 comprises CCRL2-F167Y, CCRL2-I243V, CCR5-+/Δ32, the CCR5-promoter SNP CCR5-2459A (rs1799864, previously shown to affect CCR5 expression levels and modify AIDS progression [15], [16]), CCR2-V64I, CCR3-P39L and CCR3-255T/C (Y17Y), spanning 77 Kb, and CXCR6-E3K, 318 Kb teleomeric to CCR3. The second block in 3p22, ∼10 Mb from the first block, consists of CX3CR1-V249I and -T280M and CCR8-A27G (rs2853699), which are separated by ∼160 Kb.