CR1 and Mental deterioration: Given the roles that APOE e4 and CR1 AA/AG alleles have been reported to play in the deposition of β-amyloid, the breakdown of myelin and cognitive decline (Bartzokis et al., 2007; Lambert et al., 2009; Chibnik et al., 2011), the preponderance of these risk alleles may further suggest the presence of a survival effect among this cohort.