Although it is unknown whether differences in lipoprotein metabolism in the brain exist between mice and humans, a recent cohort study revealed that Ldlr-/- patients showed a six-fold higher incidence of mild cognitive impairment compared with those without Ldlr mutations [22], indicating that LDLR may play similar roles in brain cholesterol metabolism and in maintaining brain function in both humans and mice. Here, LDLR is linked to Cognitive impairment.