rs12252

A SNP in the IFITM3 gene on chromosome 11. Its most notable genotype is G;G: possible miscall in Ancestry v2.0 datasets; otherwise, probably more susceptible to influenza

Gene
IFITM3
Location
Chr 11320,772 (GRCh38)
Highest magnitude
2.9Worth knowing
Tested on
AncestryDNA
Minor allele frequency
21%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. G;GMost notableBadpossible miscall in Ancestry v2.0 datasets; otherwise, probably more susceptible to influenzaWorth knowing · 2.9
  2. A;GBadcarrier of one allele linked to greater influenza susceptibilityMinor · 1.5
  3. A;AGoodmore resistant to influenzaTypical · 0.0

SNPedia records rs12252 on the minus strand: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Notes

From SNPedia

Show notes, about 290 words

rs12252 is a SNP in the IFITM3 gene, which encodes the interferon-inducible transmembrane protein. The rs12252(C) allele encodes an IFITM3 isoform (known as Δ21 IFITM3) which is lacking 21 amino acids at the amino terminus of the protein. In a 2012 study of ~100 hospitalized Caucasian patients with H1N1/09 influenza (flu) virus in 2009, there was a significant enrichment in individuals with rs12252(C;C) genotypes. Specifically, although 1 in 300 uninfected people were reported to carry the (C;C) genotype, in the hospitalized patients the frequency was 1 in 17.; see also MedPage However, in subsequent studies of more than 5000 subjects in two separate cohorts the association between the rs12252(C) polymorphism and the severity of H1N1 influenza could not be established, although there was a susceptibility to mild infection. The frequency of the rs12252(C) allele varies very widely between Caucasian and Asian patients; while very low in Caucasians, up to 25 - 50% of all Japanese or Chinese individuals may have the rs12252(C;C) genotype. A study of Han Chinese concluded that the rs12252(C;C) genotype was estimated to confer a sixfold greater risk for severe infection than the CT and TT genotypes.

G;G

rs12252(C;C) individuals have been reported in one study to be more susceptible to influenza and to complications from it. This has also been flagged by Promethease (as of June 2016) as potentially a SNP prone to being miscalled in data derived from the AncestryDNA v2.0 chips.

A;G

Carrying one copy of the rs12252(C) allele does not seem to make a person more susceptible to influenza, however, carrying two copies does, so this (C;T) genotype is tagged as a (unaffected) carrier of an allele linked to influenza susceptibility.

Source and license

Adapted from rs12252 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.