The gene encoding AQP4 is located on chromosome 18 (18q11.2–q12.1) [
13] (
Fig 1). Several thousand single nucleotide polymorphisms (SNPs) in the noncoding regions of
AQP4 have so far been identified, and their function(s) in the normal and diseased human brain is an active area of research. Human
AQP4 SNPs have been shown to impair cellular water permeability and water homeostasis in vitro [
14]. Moreover, an array of studies have associated human
AQP4 SNPs with neurological disorders including Alzheimer’s disease progression [
15], vascular depression phenotype [
16], leukariosis [
17], outcome after traumatic head injury [
18], edema formation [
19,
20], and the risk of stroke [
21]. These findings suggest a link between AQP4 and the development of brain diseases associated with waste deposition and fluid movements. Recently, a single variant within
AQP4 was associated with a 15% to 20% change in AQP4 expression [
22].
)