{{Rsnum
|rsid=9951307
|Gene=AQP4
|Chromosome=18
|position=26850565
|Orientation=plus
|GMAF=0.2957
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 44.2 | 39.8 | 15.9
| HCB | 61.0 | 33.8 | 5.1
| JPT | 70.5 | 26.8 | 2.7
| YRI | 37.4 | 47.6 | 15.0
| ASW | 38.6 | 50.9 | 10.5
| CHB | 61.0 | 33.8 | 5.1
| CHD | 78.9 | 19.3 | 1.8
| GIH | 48.5 | 43.6 | 7.9
| LWK | 40.4 | 45.9 | 13.8
| MEX | 69.0 | 25.9 | 5.2
| MKK | 46.5 | 44.5 | 9.0
| TSI | 42.2 | 49.0 | 8.8
| HapMapRevision=28
}}
[[rs9951307]]is a SNP in the aquaporin-4 (AQP4) gene; the corresponding protein is the main water channel in the brain and is implicated in the development of brain edema after an ischemic [[stroke]].

A study of 41 patients with middle cerebral artery occlusion with and without severe brain edema found that [[rs9951307]] was associated with severe brain edema (dominant model, p=0.01; OR, 0.10, CI: 0.02 to 0.49 for the protective (G) allele).{{PMID|18309154}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | Affy GenomeWide 6}}
{{on chip | FTDNA2}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}