rs518147

A SNP in the HTR2C gene on chromosome X. Its most notable genotype is G;G: less weight gain if taking olanzapine

Gene
HTR2C
Location
Chr X114,584,109 (GRCh38)
Highest magnitude
0.0Typical
Tested on
23andMe, AncestryDNA
Minor allele frequency
29%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. G;GMost notableNot ratedless weight gain if taking olanzapineTypical · 0.064% of people
  2. C;GNot ratednormalTypical · 0.019% of people
  3. C;CNot ratednormalTypical · 0.017% of people

SNPedia records rs518147 on the minus strand: (C;C), (C;G), (G;G). 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.

  • AverageG;G 64% C;G 19% C;C 17%
  • European ancestry (Utah)G;G 46% C;G 32% C;C 22%
  • Han Chinese (Beijing)G;G 78% C;G 9% C;C 13%
  • Japanese (Tokyo)G;G 80% C;G 11% C;C 9%
  • Yoruba (Nigeria)G;G 52% C;G 22% C;C 25%

Conditions, medicines and genes

Other HTR2C SNPs

All HTR2C SNPs

Genosets

Genosets combine several genotypes. Twofold checks them in your report.

Notes

From SNPedia

Show notes, about 200 words

rs518147, also known as -697G/C, is a SNP in the 5-hydroxytryptamine (serotonin) receptor 2C HTR2C gene. A study of 107 patients with schizophrenia being treated with olanzapine reported a protective effect against weight-gain from the (C) allele of this SNP; fewer patients (of 28) with a rs518147(C) allele had a body mass index increase of >=10% (p=0.0006), whereas (G;G) homozygotes did. This effect may also involve nearby SNP rs3813929. The association between HTR2C polymorphisms and obesity in psychiatric patients using antipsychotics: a cross-sectional study. The association between HTR2C gene polymorphisms and the metabolic syndrome in patients with schizophrenia. Multivariate permutation analysis associates multiple polymorphisms with subphenotypes of major depression. HTR2C gene polymorphisms and the metabolic syndrome in patients with schizophrenia: a replication study. Association of polymorphisms of the serotonergic system with smoking initiation in Caucasians. HTR2C promoter polymorphisms are associated with risperidone efficacy in Chinese female patients. Functional consequences of two HTR2C polymorphisms associated with antipsychotic-induced weight gain.

Source and license

Adapted from rs518147 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.