In one study, it was shown that variation in the ABCA7 gene is associated with an increased risk of Alzheimer’s disease in women with reduced levels of oestrogen at menopause.77 In an animal study, it was suggested that cessation of the oestrous cycling in female mice is a factor in the reduction in spatial reference memory performance in female Abca7 KO mice.24 Much work is needed to understand the exact relationship between ABCA7 and oestrogen, and subsequent effects on Alzheimer’s disease pathogenesis. This evidence concerns the gene ABCA7 and Alzheimer disease.