rs1843809

A SNP in the TPH2 gene on chromosome 12. Its most notable genotype is G;G: slightly decreased risk for ADHD

Gene
TPH2
Location
Chr 1271,954,918 (GRCh38)
Highest magnitude
1.5Minor
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
19%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. G;GMost notableGoodslightly decreased risk for ADHDMinor · 1.57% of people
  2. T;TNot ratedMost common genotype worldwideMinor · 1.064% 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 7% T;T 64%
  • European ancestry (Utah)G;G 2% T;T 80%
  • Han Chinese (Beijing)G;G 2% T;T 87%
  • Japanese (Tokyo)G;G <1% T;T 96%
  • Yoruba (Nigeria)G;G 17% T;T 33%
  • African ancestry (Southwest US)G;G 16% T;T 40%
  • Chinese (Denver)G;G 0% T;T 86%
  • Gujarati IndianG;G 1% T;T 80%
  • Luhya (Kenya)G;G 20% T;T 37%
  • Mexican ancestry (Los Angeles)G;G 0% T;T 67%
  • Maasai (Kenya)G;G 14% T;T 32%
  • TuscanG;G 4% T;T 67%

Other TPH2 SNPs

All TPH2 SNPs

Notes

From SNPedia

Notes

Tryptophan hydroxylase 2 (TPH2) gene variants associated with ADHD. Preferential transmission of paternal alleles at risk genes in attention-deficit/hyperactivity disorder. The analysis of 51 genes in DSM-IV combined type attention deficit hyperactivity disorder: association signals in DRD4, DAT1 and 16 other genes.

G;G

G allele associated with slightly decreased risk for ADHD https://www.nature.com/articles/4001698

Source and license

Adapted from rs1843809 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.