rs17261572

A SNP in the C1GALT1C1 gene on chromosome X. Its most notable genotype is T;T: Tn polyagglutination syndrome; somatic mutation

Gene
C1GALT1C1
Location
Chr X120,626,774 (GRCh38)
Highest magnitude
2.0Worth knowing
Tested on
23andMe, AncestryDNA
Minor allele frequency
13%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AGoodcommon in clinvarTypical · 0.085% of people
  2. A;TBadTn polyagglutination syndrome; somatic mutationMinor · 1.510% of people
  3. T;TMost notableBadTn polyagglutination syndrome; somatic mutationWorth knowing · 2.06% of people

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

Frequency

Share of each genotype in 11 HapMap populations.

  • AverageA;A 85% A;T 10% T;T 6%
  • European ancestry (Utah)A;A 60% A;T 20% T;T 21%
  • Han Chinese (Beijing)A;A 85% A;T 12% T;T 4%
  • Japanese (Tokyo)A;A 91% A;T 7% T;T 2%
  • Yoruba (Nigeria)A;A 100% A;T 0% T;T 0%
  • African ancestry (Southwest US)A;A 93% A;T 7% T;T 0%
  • Chinese (Denver)A;A 83% A;T 12% T;T 6%
  • Gujarati IndianA;A 71% A;T 17% T;T 12%
  • Luhya (Kenya)A;A 99% A;T 0% T;T <1%
  • Mexican ancestry (Los Angeles)A;A 78% A;T 17% T;T 5%
  • Maasai (Kenya)A;A 94% A;T 5% T;T 1%
  • TuscanA;A 77% A;T 12% T;T 11%

Notes

From SNPedia

Notes

A;T

Tn polyagglutination syndrome is most often seen in males, and this *somatic* mutation has been reported to lead to it. However, note that this is a genotype that is way more common than Tn polyagglutination syndrome; in other words, there are a lot of people born with this genotype who do not show signs of Tn polyagglutination syndrome.

T;T

Tn polyagglutination syndrome is most often seen in males, and this *somatic* mutation has been reported to lead to it. However, note that this is a genotype that is way more common than Tn polyagglutination syndrome; in other words, there are a lot of people born with this genotype who do not show signs of Tn polyagglutination syndrome.

Source and license

Adapted from rs17261572 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.