{{Rsnum
|rsid=518147
|Gene=HTR2C
|Chromosome=X
|position=114584109
|Orientation=minus
|GMAF=0.2926
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(C;C)
|geno2=(C;G)
|geno3=(G;G)
|Gene_s=HTR2C
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;G)
| geno3=(G;G)
| CEU | 46.2 | 32.3 | 21.5
| HCB | 77.8 | 8.9 | 13.3
| JPT | 79.5 | 11.4 | 9.1
| YRI | 52.4 | 22.2 | 25.4
| ASW | 0.0 | 0.0 | 0.0
| CHB | 77.8 | 8.9 | 13.3
| CHD | 0.0 | 0.0 | 0.0
| GIH | 0.0 | 0.0 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 0.0 | 0.0 | 0.0
| MKK | 0.0 | 0.0 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}
[[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]].{{PMID|19434072}}

{{PMID Auto
|PMID=19416518
|Title=Investigation of the serotonin 2C receptor gene in attention deficit hyperactivity disorder in UK samples
|OA=1
}}

{{PharmGKB
|RSID=rs518147
|Name_s=HTR2C: -697G/C
|Gene_s=HTR2C
|Feature=
|Evidence=PubMed ID:19622037
|Annotation=This variant is associated with Olanzapine-induced weight gain. The -697C allele confers protective effect towards Olanzapine-induced weight gain in a study consisting of 107 patients with schizophrenia.
|Drugs=olanzapine
|Drug Classes=
|Diseases=Schizophrenia; Weight gain
|Curation Level=Curated
|PharmGKB Accession ID=PA164924605
}}

{{PMID|17016522}} The association between HTR2C polymorphisms and obesity in psychiatric patients using antipsychotics: a cross-sectional study.

{{PMID|17632216}} The association between HTR2C gene polymorphisms and the metabolic syndrome in patients with schizophrenia.

{{PMID|18081710|OA=1
}} Multivariate permutation analysis associates multiple polymorphisms with subphenotypes of major depression.

{{PMID|19142101}} HTR2C gene polymorphisms and the metabolic syndrome in patients with schizophrenia: a replication study.

{{PMID|20060656}} Association of polymorphisms of the serotonergic system with smoking initiation in Caucasians.

{{PMID|20415561}} HTR2C promoter polymorphisms are associated with risperidone efficacy in Chinese female patients.

{{PMID|21391883}} Functional consequences of two HTR2C polymorphisms associated with antipsychotic-induced weight gain.

{{GET Evidence
|impact=pharmacogenetic
|qualified_impact=Insufficiently evaluated pharmacogenetic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs518147
|overall_frequency_n=31
|overall_frequency_d=86
|overall_frequency=0.360465
|n_genomes=25
|n_genomes_annotated=0
|n_haplomes=40
|n_articles=1
|n_articles_annotated=0
|in_pharmgkb=Y
|autoscore=1
|webscore=N
}}

{{PMID Auto
|PMID=22914617
|Title=Analysis of the BTBD9 and HTR2C variants in Chinese Han patients with Tourette syndrome.
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | HumanOmni1Quad}}