Hi CDiddy. Thank you! To put it simply The normal
variant of the ccr5 gene seems to create a neuro inflammatory response in the limbic cortex and anterior singulate areas of the brain which on a functional/phenotypic level seems to literally make us forget. In fact it's estimated that ~10 percent of individuals w true photographic memory are homozygous for the deletion variant of the ccr5 gene. What we don't really know is if there is a partial lessening of the effect in individuals who are heterozygous for the deletion variant I.e. have one copy of the normal gene and one deletion variant.