Markers / Gene
NOD2
One position in this gene is readable from a home DNA test.
NOD2, the first Crohn's gene ever found
rs2066844 · chr16:50,745,926 · C/T · evidence: established
NOD2 senses a fragment of bacterial cell wall inside your own cells. The variant version senses it less well, and the gut's relationship with its bacteria goes wrong. This was the first gene ever linked to a common inflammatory disease by genetics, and like PTPN22 it is a European variant, absent from East Asian populations where Crohn's disease is caused differently.
| If you carry | What it means |
|---|---|
| No copies | You do not carry it |
| One copy | You carry one copy |
| Two copies | You carry two copies |
| Ancestry group | T (the effect version) | |
|---|---|---|
| African | 0.2% | |
| American | 2.4% | |
| East Asian | 0.0% | |
| European | 5.1% | |
| South Asian | 0.1% |
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.
Read my file