Similarly, the observed association between increasing AQP4 expression in the HIP and dementia status is consistent with our prior finding that increased AQP4 expression and loss of perivascular localization predicted AD status, and that naturally occurring single-nucleotide polymorphisms in the human AQP4 gene are associated with altered rates of neurocognitive decline among subjects with AD14,21. This evidence concerns the gene AQP4 and Alzheimer disease.