In a small study of 39 Alzheimer’s disease patients and 20 healthy participants (unknown APOE genotype), HDL isolated from plasma showed a diminished HDL cholesterol efflux capacity (CEC) and lecithin-cholesterol acyltransferase (LCAT) activity—the enzyme responsible for increasing the HDL cholesterol carrying capacity—and the level of LCAT activity was negatively correlated with the cognitive score [10]. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.