rs2395029
Abacavir hypersensitivity marker
What this position does
Abacavir, an HIV medicine, causes a dangerous hypersensitivity reaction in people carrying HLA-B*57:01. Testing before prescribing is mandatory, and it is one of the clearest successes in the whole field.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version TT | Tag not detected This tag is absent, which argues against carrying HLA-B*57:01. |
| One copy GT | Tag detected This tag is strongly linked to HLA-B*57:01. If abacavir is ever proposed, say so. Proper HLA typing is done before prescribing in any case, so this changes nothing clinically, but it is worth knowing. |
| Two copies GG | Tag detected, two copies As above. Proper HLA typing is the test that counts. |
Worth knowing. A tag in strong linkage with the real allele, not the allele itself. The link is weaker outside European populations.
How common each version is
| Ancestry group | G (the effect version) | |
|---|---|---|
| African | 0.5% | |
| American | 2.0% | |
| East Asian | 1.2% | |
| European | 4.4% | |
| South Asian | 9.3% |
1000 Genomes Project phase 3, via Ensembl, retrieved 2026-09-23. These groupings are coarse and flatten a great deal of internal diversity, particularly within Africa. A variant being common somewhere tells you where a piece of your ancestry probably comes from, and nothing else.
How many people carry each result
| Ancestry group | TT | GT | GG |
|---|---|---|---|
| African | 655 / 661 | 6 / 661 | 0 / 661 |
| European | 459 / 503 | 44 / 503 | 0 / 503 |
| East Asian | 492 / 504 | 12 / 504 | 0 / 504 |
| South Asian | 401 / 489 | 85 / 489 | 3 / 489 |
| American | 333 / 347 | 14 / 347 | 0 / 347 |
Counts of people, not modelled frequencies: every one of the 2,504 individuals sequenced by the 1000 Genomes Project phase 3, tallied by the genotype they carry. Deriving these from allele frequencies instead would assume random mating inside each group and undercount the homozygotes.
How to find out which you have
If you have taken a test with 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, TellMeGen or Living DNA, this position is very likely already in the raw data file they gave you. You do not need another test.
One thing to watch if you look it up by hand: testing companies report some positions from one DNA strand and some from the other, and the file does not say which. Read the letters as they appear and you will get the opposite of the truth for some positions. Sequencings resolves that automatically.
Source
CPIC Guideline for Abacavir and HLA-B
Coordinates and allele pair verified against Ensembl GRCh37. Direction of effect verified against VEP protein consequences or 1000 Genomes population frequency. Category: Medicine response.
Where this fits
Common questions
What is rs2395029?
rs2395029 is a position in the HCP5 gene on chromosome 6. Abacavir, an HIV medicine, causes a dangerous hypersensitivity reaction in people carrying HLA-B*57:01. Testing before prescribing is mandatory, and it is one of the clearest successes in the whole field.
What does it mean if I have GG at rs2395029?
Tag detected, two copies. As above. Proper HLA typing is the test that counts.
What does it mean if I have TT at rs2395029?
Tag not detected. This tag is absent, which argues against carrying HLA-B*57:01.
How do I find out my rs2395029 genotype?
If you have taken a home DNA test, this position is very likely in the raw data file you were given. Sequencings reads that file in your browser without uploading it, and resolves which DNA strand each position was reported from, which is the step most manual lookups get wrong.
This is reference information, not medical advice, and not a diagnosis. See the medical disclaimer. Category: Medicine response.