rs121908745
A SNP in the CFTR gene on chromosome 7. Its most notable genotype is -;ATC: carrier of a cystic fibrosis allele
- Gene
- CFTR
- Location
- Chr 7117,559,590 (GRCh38)
- Highest magnitude
- 3.0Important
- Tested on
- AncestryDNA
Genotypes
As shown in 23andMe and AncestryDNA files.
- -;ATCMost notableBadcarrier of a cystic fibrosis allele
- A;AGoodCommon (in Ancestry reports); no need to worry
- ATC;ATCGoodcommon in clinvar
On SNPedia: (-;ATC), (A;A), (ATC;ATC). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other CFTR SNPs
- i4000292D;Dcystic fibrosisVery important
- rs74551128A;ACystic fibrosisVery important
- rs113993960-;-Cystic Fibrosis; homozygote for delta F-508 mutationVery important
- rs199826652-;-Cystic Fibrosis; homozygote for delta F-508 mutationVery important
- i4000309A;ACystic FibrosisVery important
- i4000294A;ACystic FibrosisVery important
- i4000296T;TCystic FibrosisVery important
- i4000297A;ACystic FibrosisVery important
Notes
From SNPedia
Notes
Cystic fibrosis; c.1519_1521delATC, p.Ile507del
-;ATC
Cystic fibrosis mutation carrier; unaffected unless CF mutation present on other copy of CF gene
A;A
The (A;A) genotype is the most commonly reported one for Ancestry users, so it's the common/normal form. However, in public databases, rs121908745 should be either "ATC" or "nothing", in other words, a deletion of the "ATC", so to report (A;A) as a possible genotype for this SNP is actually an error on Ancestry's part.
Source and license
Adapted from rs121908745 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.