rs1021737

A SNP in the CTH gene on chromosome 1. Its most notable genotype is T;T: significantly higher plasma total homocysteine concentration

Gene
CTH
Location
Chr 170,439,117 (GRCh38)
Highest magnitude
3.0Important
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
23%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. G;GGoodcommon in clinvarTypical · 0.066% of people
  2. T;TMost notableBadsignificantly higher plasma total homocysteine concentrationImportant · 3.05% of people

On SNPedia: (G;G), (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.

  • AverageG;G 66% T;T 5%
  • European ancestry (Utah)G;G 55% T;T 7%
  • Han Chinese (Beijing)G;G 62% T;T 6%
  • Japanese (Tokyo)G;G 59% T;T 4%
  • Yoruba (Nigeria)G;G 87% T;T 0%
  • African ancestry (Southwest US)G;G 72% T;T 0%
  • Chinese (Denver)G;G 72% T;T 5%
  • Gujarati IndianG;G 56% T;T 5%
  • Luhya (Kenya)G;G 86% T;T 0%
  • Mexican ancestry (Los Angeles)G;G 28% T;T 22%
  • Maasai (Kenya)G;G 91% T;T 0%
  • TuscanG;G 58% T;T 2%

Other CTH SNPs

All CTH SNPs

Source and license

Adapted from rs1021737 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.