rs11803731

A SNP in the TCHH gene on chromosome 1. Its most notable genotype is A;A: straighter hair

Gene
TCHH
Location
Chr 1152,110,849 (GRCh38)
Highest magnitude
2.0Worth knowing
Tested on
23andMe, AncestryDNA
Minor allele frequency
10%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AMost notableNot ratedstraighter hairWorth knowing · 2.089% of people
  2. T;TNot ratedcurlier hairWorth knowing · 2.02% of people

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

Frequency

Share of each genotype in 4 HapMap populations.

  • AverageA;A 89% T;T 2%
  • European ancestry (Utah)A;A 58% T;T 8%
  • Han Chinese (Beijing)A;A 98% T;T 0%
  • Japanese (Tokyo)A;A 100% T;T 0%
  • Yoruba (Nigeria)A;A 100% T;T 0%

Other TCHH SNPs

All TCHH SNPs

Notes

From SNPedia

Notes

rs11803731, a SNP in the Trichohyalin gene (TCHH) gene, is estimated to account for 6% of the variance in hair morphology (ie hair curliness) based on a study of Australians of European ancestry. A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features

Source and license

Adapted from rs11803731 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.