{{Rsnum
|rsid=12343867
|Gene=JAK2
|Chromosome=9
|position=5074189
|Orientation=plus
|GMAF=0.2576
|Assembly=GRCh37
|GenomeBuild=37.1
|dbSNPBuild=131
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
}}
{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 7.5 | 47.2 | 45.3
| HCB | 7.3 | 31.7 | 61.0
| JPT | 2.4 | 52.4 | 45.2
| YRI | 0.0 | 0.0 | 0.0
| ASW | 0.0 | 0.0 | 0.0
| CHB | 7.3 | 31.7 | 61.0
| CHD | 0.0 | 0.0 | 0.0
| GIH | 0.0 | 0.0 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 0.0 | 0.0 | 0.0
| MKK | 0.0 | 0.0 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}

{{omim
|desc=JANUS KINASE 2; JAK2
|id=147796
|rsnum=12343867
}}

{{PMID Auto
|PMID=19847199
|Title=JAK2 germline genetic variation affects disease susceptibility in primary myelofibrosis regardless of V617F mutational status: nullizygosity for the JAK2 46/1 haplotype is associated with inferior survival
}}
{{PMID Auto
|PMID=21791467
|Title=The prognostic impact of germline 46/1 haplotype of Janus kinase 2 in cytogenetically normal acute myeloid leukemia
|OA=1
}}
{{PMID Auto
|PMID=22251709
|Title=The C allele of the JAK2 rs4495487 is an additional candidate locus that contributes to myeloproliferative neoplasm predisposition in the Japanese population
|OA=1
}}

[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 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. n 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]]



{{PMID|19847198}} The JAK2 46/1 haplotype confers susceptibility to essential thrombocythemia regardless of JAK2V617F mutational status-clinical correlates in a study of 226 consecutive patients.

{{PMID|19922437}} The JAK2 rs12343867 CC genotype frequently occurs in patients with splanchnic venous thrombosis without the JAK2V617F mutation: a retrospective study.

{{PMID|21173100|OA=1
}} The role of the JAK2 GGCC haplotype and the TET2 gene in familial myeloproliferative neoplasms.

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

{{PMID|21364191}} The JAK2 46/1 haplotype in Budd-Chiari syndrome and portal vein thrombosis.

{{PMID|21497883}} Sex modulation of the occurrence of jak2 v617f mutation in patients with splanchnic venous thrombosis.
{{PMID Auto
|PMID=23188718
|Title=The influence of novel transcriptional regulatory element in intron 14 on the expression of Janus kinase 2 gene in myeloproliferative neoplasms
}}
{{PMID Auto
|PMID=23845539
|Title=The association of the JAK2 46/1 haplotype with non-splanchnic venous thrombosis
}}