{{Rsnum
|rsid=12340895
|Gene=JAK2
|Chromosome=9
|position=5076691
|Orientation=plus
|GMAF=0.2489
|Assembly=GRCh37
|GenomeBuild=37.1
|dbSNPBuild=131
|geno1=(C;C)
|geno2=(C;G)
|geno3=(G;G)
}}
{{ population diversity
| geno1=(C;C)
| geno2=(C;G)
| geno3=(G;G)
| CEU | 50.8 | 43.1 | 6.2
| HCB | 56.7 | 35.8 | 7.5
| JPT | 56.8 | 36.9 | 6.3
| YRI | 75.7 | 24.3 | 0.0
| ASW | 66.7 | 31.6 | 1.8
| CHB | 56.7 | 35.8 | 7.5
| CHD | 52.4 | 43.8 | 3.8
| GIH | 61.5 | 32.3 | 6.2
| LWK | 68.2 | 28.0 | 3.7
| MEX | 37.5 | 55.4 | 7.1
| MKK | 59.2 | 38.2 | 2.6
| TSI | 50.5 | 44.4 | 5.1
| HapMapRevision=28
}}

{{omim
|desc=JANUS KINASE 2; JAK2
|id=147796
|rsnum=12340895
}}

[http://blog.23andme.com/2012/03/05/snpwatch-the-jist-on-jak2-and-myeloproliferative-neoplasms/ 23andMe blog]
At rs12340895(G) (equivalent to rs12343867 in the study) had nearly four times higher odds of developing V617F-positive [[myelofibrosis]] (MPN) compared to people without the disease. "23andMe recently replicated this association, though we see a smaller effect — in our database, people with a G at rs12340895 have about two times the odds of developing V617F-positive MPN compared to people without the disease. People with an A at rs3780374 in the JAK2 gene (equivalent to rs4495487 reported in the study and highly correlated with rs12343867) have about three times higher odds of developing V617F-positive MPN compared to individuals without the A version."

The following SNPs are (all) associated with the JAK2 46/1 haplotype that appears to predispose to V617F-positive neoplasms; since they are all part of one haplotype (and are not independent of one another), having one usually implies having the others as well.

*[[rs12343867]]
*[[rs12340895]]
*[[rs3780374]]
*[[rs4495487]]
*[[rs10974944]]


For results applicable to those with Asian ancestry, use [[rs3780374]]. For results applicable to those with European ancestry, use [[rs12340895]].


{{PMID Auto
|PMID=21281225
|Title=JAK2V617F mutation is associated with special alleles in essential thrombocythemia.
}}

{{PMID Auto
|PMID=23054641
|Title=The JAK2 46/1 haplotype is a risk factor for myeloproliferative neoplasms in Chinese patients
}}

{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | Affy GenomeWide 6}}