GENE REFERENCE / HGNC:6192
JAK2
Janus kinase 2
What does this gene do?
The JAK2 gene provides instructions for making a protein that promotes the growth and division (proliferation) of cells. This protein is part of a signaling pathway called the JAK/STAT pathway, which transmits chemical signals from outside the cell to the cell's nucleus. The JAK2 protein is especially important for controlling the production of blood cells from hematopoietic stem cells. These stem cells are located within the bone marrow and have the potential to develop into red blood cells, white blood cells, and platelets.
Related condition topics
MedlinePlus mentions this gene in the condition pages below. These links alone do not show that the gene causes a condition.
ClinGen reviews
We found no matching ClinGen review in the data used here. This does not rule out a link between the gene and a condition.
ClinVar records
These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.
- Submitted alleles
- 817
- Submissions for variants in or overlapping this gene
- 1,117
- Submissions explicitly reporting this gene
- 904
- Alleles reported pathogenic / likely pathogenic
- 12
- VariationIDs with uncertain significance
- 357
- VariationIDs with conflicting classifications
- 19
The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.
NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗
YOUR DNA FILE
Can your DNA file tell you about JAK2?
From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 12 alleles in JAK2 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.
From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.
If a variant is not in your file, that does not mean you don’t have it.
What BioDecode checks
BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.
A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in JAK2.
BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.
Sources and dates
The source information on this page last changed on 2026-10-10.
HGNC Source details
Source release: Fri, 09 Oct 2026 13:40:45 GMT
Source record updated: 2023-01-20
SHA-256: e4cd9c6d7120051b80e5e61d2aeb98bd6a541ddd21f428a6eab922c11242e053
MedlinePlus Source details
Source release: Sat, 10 Oct 2026 05:16:07 GMT
Source publication: 2020-08-18
Source review: 2014-09
SHA-256: fdc8bd614310c12718379cef6569962e5d0e791cecabcc355b53a72816ac263a
ClinVar Source details
Source release: Sun, 04 Oct 2026 13:15:29 GMT
SHA-256: 126d9e5bded1d43c0380ac6684c86f9aab056d2ff2be93d743e408ed917ae558
About the library sources · Latest validated release · Record ed093b6c0c1e