Markers / Gene
CYP3A5
One position in this gene is readable from a home DNA test.
CYP3A5 and tacrolimus dosing
rs776746 · chr7:99,270,539 · C/T · evidence: established
CYP3A5 clears tacrolimus, the main anti-rejection drug after organ transplant. Most Europeans carry two non-working copies and are non-expressors; most people of African descent express it and need substantially higher doses.
| If you carry | What it means |
|---|---|
| No copies | Expressor |
| One copy | Intermediate |
| Two copies | Non-expressor |
| Ancestry group | C (the effect version) | |
|---|---|---|
| African | 18.0% | |
| American | 79.7% | |
| East Asian | 71.3% | |
| European | 94.3% | |
| South Asian | 66.8% |
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.
Where this gene fits
If you have taken a home DNA test, these positions are already in your file.
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