rs4495487

A SNP in the JAK2 gene on chromosome 9. Its most notable genotype is C;C: 2 - 4 fold increased odds of developing V617F-associated MPNs

Gene
JAK2
Location
Chr 95,072,798 (GRCh38)
Highest magnitude
3.0Important
Tested on
23andMe
Minor allele frequency
24%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. C;CMost notableBad2 - 4 fold increased odds of developing V617F-associated MPNsImportant · 3.04% of people
  2. C;TBadIncreased odds (2 fold?) of developing V617F-associated MPNsWorth knowing · 2.536% of people
  3. T;TGoodcommon/normalTypical · 0.060% of people

On SNPedia: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Frequency

Share of each genotype in 4 HapMap populations.

  • AverageC;C 4% C;T 36% T;T 60%
  • European ancestry (Utah)C;C 6% C;T 43% T;T 51%
  • Han Chinese (Beijing)C;C 7% C;T 29% T;T 64%
  • Japanese (Tokyo)C;C 2% C;T 49% T;T 49%
  • Yoruba (Nigeria)C;C 0% C;T 24% T;T 76%

Other JAK2 SNPs

All JAK2 SNPs

Notes

From SNPedia

Show notes, about 160 words

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 variant. 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. 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

Source and license

Adapted from rs4495487 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.