rs601338

A SNP in the FUT2 gene on chromosome 19. Its most notable genotype is A;A: resistance to Norovirus infection

Gene
FUT2
Location
Chr 1948,703,417 (GRCh38)
Highest magnitude
2.5Worth knowing
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
32%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AMost notableGoodresistance to Norovirus infectionWorth knowing · 2.516% of people
  2. A;GBadsusceptible to Norovirus infectionsTypical · 0.138% of people
  3. G;GBadsusceptible to Norovirus infectionsTypical · 0.145% of people

On SNPedia: (A;A), (A;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Frequency

Share of each genotype in 10 HapMap populations.

  • AverageA;A 16% A;G 38% G;G 45%
  • European ancestry (Utah)A;A 30% A;G 46% G;G 24%
  • Han Chinese (Beijing)A;A 0% A;G 3% G;G 97%
  • Japanese (Tokyo)A;A 0% A;G 2% G;G 98%
  • Yoruba (Nigeria)A;A 27% A;G 54% G;G 19%
  • African ancestry (Southwest US)A;A 30% A;G 46% G;G 23%
  • Gujarati IndianA;A 4% A;G 37% G;G 59%
  • Luhya (Kenya)A;A 22% A;G 45% G;G 33%
  • Mexican ancestry (Los Angeles)A;A 9% A;G 57% G;G 35%
  • Maasai (Kenya)A;A 16% A;G 46% G;G 39%
  • TuscanA;A 24% A;G 48% G;G 28%

Other FUT2 SNPs

All FUT2 SNPs

Notes

From SNPedia

Show notes, about 370 words

rs601338 is found on chromosome 19 in the alpha(1,2)-fucosyltransferase FUT2 gene. The wild-type rs601338(G) encodes the "secretor" (Se) allele, while rs601338(A) encodes the "non-secretor" (se) allele. A study of 115 Swedish adults concluded that rs601338(A;A) homozygotes have genetic immunity to infection by the Norwalk norovirus, a major (and contagious) cause of acute gastroenteritis worldwide among adults. This illness is also known as "cruise ship gastroenteritis." Being a non-secretor may have other consequences, such as greater susceptibility to infection by influenza viruses and by some types of bacteria. 23andMe discusses these topics. In some non-Caucasian populations, a different SNP is responsible for non-secretor phenotypes. For example, although the Se allele is absent in Japanese, 15% are non-secretors based on being homozygous for the non-secretor "sej" allele of SNP rs1047781. It also appears to affect the composition of the microbiome plosone.org, with secretors apparently having higher levels of Bifidobacteria. http://blog.personalgenomes.org/2012/02/29/invulnerability-to-stomach-flu-is-my-secret-superpower/ http://evidence.personalgenomes.org/FUT2-W154X Novel association of ABO histo-blood group antigen with soluble ICAM-1: results of a genome-wide association study of 6,578 women. Common variants of FUT2 are associated with plasma vitamin B12 levels. Histo-blood group gene polymorphisms as potential genetic modifiers of infection and cystic fibrosis lung disease severity. Development of a fingerprinting panel using medically relevant polymorphisms. Potential etiologic and functional implications of genome-wide association loci for human diseases and traits. Common genetic variation and the control of HIV-1 in humans. Population based allele frequencies of disease associated polymorphisms in the Personalized Medicine Research Project. FUT2 nonsecretor status links type 1 diabetes susceptibility and resistance to infection. Norovirus Resistance

A;A

This genotype confers genetic immunity to infection by the Norwalk norovirus, a major (and contagious) cause of acute gastroenteritis worldwide.

References

Source and license

Adapted from rs601338 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.