{{Rsnum
|rsid=77375493
|Gene=JAK2
|Chromosome=9
|position=5073770
|Orientation=plus
|GMAF=0.0
|Gene_s=JAK2
|Assembly=GRCh37.p5
|GenomeBuild=37.3
|dbSNPBuild=135
|geno1=(G;G)
|geno2=(G;T)
|geno3=(T;T)
}}
[[rs77375493]], also known as V617F or Val617Phe, is a variant considered to generally be acquired (i.e. somatic) in the Janus kinase 2 [[JAK2]] gene. The wild-type (normal) allele is [[rs77375493]](G), and the (very rare) variant allele is [[rs77375493]](T).

While the predictive medical consequences of having the variant in the absence of symptoms remain uncertain, this variant has been reported to be associated with several myeloproliferative disorders (basically, cancers of the blood), including [[polycythemia vera]], essential [[thrombocythemia]], and idiopathic [[myelofibrosis]], and it appears to be act in a dominant manner. See: OMIM [http://omim.org/entry/147796#0001 147796.0001].

A participant in the PGP, John Lauerman, has published an [http://www.bloomberg.com/news/2012-02-15/harvard-mapping-my-dna-turns-scary-as-threatening-gene-emerges.html article] about his experiences upon finding out that he carried this variant.
{{omim
|id=147796
|variant=0001
|rsnum=77375493
}}

{{ClinVar
|rsid=77375493
|Reversed=0
|FwdREF=G
|FwdALT=A,T
|REF=G
|ALT=A,T
|RSPOS=5073770
|CHROM=9
|GMAF=0
|dbSNPBuildID=131
|SSR=0
|SAO=3
|VP=0x050260000000000416110120
|GENEINFO=JAK2:3717
|GENE_NAME=JAK2
|GENE_ID=3717
|WGT=0
|VC=SNV
|CLNALLE=1; 2
|CLNHGVS=NC_000009.11:g.5073770G>A; NC_000009.11:g.5073770G>T
|CLNORIGIN=1
|CLNSIG=255
|Tags=PM;S3D;HD;KGPhase1;KGPROD;OTHERKG;LSD;OM
|CAF=1; 0
|CLNACC=RCV000022629.24; RCV000015769.1; RCV000015770.1; RCV000015771.1; RCV000015772.33; RCV000022627.1; RCV000022628.1
|CLNDBN=Thrombocythemia 3; Polycythemia vera, somatic; Myelofibrosis, somatic; Leukemia, acute myelogenous, somatic; Budd-Chiari syndrome, susceptibility to, somatic; THROMBOCYTHEMIA 3, SOMATIC; ERYTHROCYTOSIS, SOMATIC
|CLNDSDB=MedGen:OMIM:Orphanet
|CLNDSDBID=C3281125:614521:3318
|CLNSRC=OMIM Allelic Variant
|CLNSRCID=147796.0004; 147796.0001
|COMMON=0
|Disease=Thrombocythemia 3; Polycythemia vera; Myelofibrosis; Leukemia; Budd-Chiari syndrome; THROMBOCYTHEMIA 3; ERYTHROCYTOSIS
}}

{{GET Evidence
|gene=JAK2
|aa_change=Val617Phe
|aa_change_short=V617F
|impact=pathogenic
|qualified_impact=High clinical importance,  pathogenic
|inheritance=dominant
|quality_scores=Array
|dbsnp_id=rs77375493
|overall_frequency_n=3
|overall_frequency_d=10756
|overall_frequency=0.000278914
|n_genomes=1
|n_genomes_annotated=0
|n_haplomes=1
|n_articles=12
|n_articles_annotated=11
|qualityscore_in_silico=1
|qualitycomment_in_silico=Y
|qualityscore_in_vitro=4
|qualitycomment_in_vitro=Y
|qualityscore_case_control=5
|qualitycomment_case_control=Y
|qualityscore_familial=0
|qualitycomment_familial=Y
|qualityscore_severity=4
|qualitycomment_severity=Y
|qualityscore_treatability=4
|qualitycomment_treatability=Y
|gene_in_genetests=Y
|in_omim=Y
|pph2_score=0.997
|nblosum100=3
|autoscore=4
|webscore=N
|n_web_uneval=10
|variant_evidence=2
|clinical_importance=2
|summary_short=This well known variant is associated with myeloproliferative diseases: it is used as a diagnostic, providing supporting evidence in individuals who already have symptoms. It is seen as an acquired (not inherited) mutation, one of an accumulation of changes that leads to the development of these cancer-like diseases. It is possible to see this variant in whole genome data or genotyping from blood-derived DNA -- but it is unclear how to view the presence of the variant in individuals who don't have symptoms of the disease. Data from Nielsen et al. suggests that such carriers are at much higher risk of developing myeloproliferative disease or other blood cancer (with roughly 50% of still-living individuals developing these diseases by around 10 years after initial samples -- but these numbers are _extremely_ uncertain).
}}

{{on chip | 23andMe v3}}