rs6323

A SNP in the MAOA gene on chromosome X. Its most notable genotype is T;T: reduced MAOA activity

Gene
MAOA
Location
Chr X43,731,789 (GRCh38)
Highest magnitude
3.0Important
Tested on
23andMe, AncestryDNA
Minor allele frequency
33%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. G;GNot ratedIncreased monoamine oxidase A activityWorth knowing · 2.126% of people
  2. T;TMost notableNot ratedreduced MAOA activityImportant · 3.055% 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 26% T;T 55%
  • European ancestry (Utah)G;G 17% T;T 66%
  • Han Chinese (Beijing)G;G 49% T;T 25%
  • Japanese (Tokyo)G;G 43% T;T 28%
  • Yoruba (Nigeria)G;G 5% T;T 88%
  • African ancestry (Southwest US)G;G 7% T;T 68%
  • Chinese (Denver)G;G 51% T;T 24%
  • Gujarati IndianG;G 51% T;T 30%
  • Luhya (Kenya)G;G 6% T;T 87%
  • Mexican ancestry (Los Angeles)G;G 19% T;T 57%
  • Maasai (Kenya)G;G 14% T;T 75%
  • TuscanG;G 22% T;T 60%

Other MAOA SNPs

All MAOA SNPs

Notes

From SNPedia

Notes

rs6323 (R297R / Arg297Arg) is a SNP in the MAOA (monoamine oxidase A) gene. Monoamine oxidase A degrades serotonin, dopamine, epinephrine, and norepinephrine. The G allele encodes for the higher activity form of the enzyme. Subjects with major depressive disorder with the highest activity form of the enzyme (G or G/G) had a significantly lower magnitude of placebo response.

Source and license

Adapted from rs6323 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.