{{Rsnum
|rsid=6318
|Gene=HTR2C
|Chromosome=X
|position=114731326
|Orientation=plus
|ReferenceAllele=G
|MissenseAllele=C
|GMAF=0.1663
|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 | 9.2 | 13.8 | 76.9
| HCB | 2.2 | 2.2 | 95.6
| JPT | 4.5 | 2.3 | 93.2
| YRI | 33.3 | 30.2 | 36.5
| ASW | 0.0 | 0.0 | 0.0
| CHB | 2.2 | 2.2 | 95.6
| 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
}}
[[rs6318]] (Cys23Ser / C23S or 68G>C / G68C) is a SNP within the serotonin 2C receptor [[HTR2C]] gene located on the X chromosome. Since it is located on the X chromosome, males will be hemizygous and either (C;-) or (G;-), whereas females will either homozygous (C;C) or (G;G) or heterozygous (C;G). In most of the studies cited below, heterozyous (C;G) females were roughly statistically equivalent to females carrying the common non-risk (G;G) genotype.

One relatively large (4,000 men and 2,000 women) study published in late 2013 of Caucasian catheterization patients has studied the association between [[rs6318]] genotype and risk of having an "end" cardiac event, defined as either death or a heart attack, in the years following entry into the study (i.e. presumably following their catheterization). Patients were followed for up to 11 years, with a median follow-up time of 5.3 years. Different [[rs6318]] genotypes had statistically significant differences in their odds of having end cardiac events as follows: 29% of (G;-) men; 35% of (C;-) men; ~26% of (G;G) or (C;G) women; and 36% of (C;C) women. This works out to hazard ratios from the fully adjusted model for male [[rs6318]](C;-) compared to the more common (G;-) males of 1.23 (CI: 1.02-1.36, p=0.02), and 1.62 (CI:1.07-2.47, p=0.02) for female (C;C) genotypes compared to the more common (G;G) females. The authors postulate that [[rs6318]] is associated with higher stress-related cortisol levels, and suggest (without any evidence so far) that [[rs6318]](C;C) women and (C;-) men may benefit from either behavioural therapy or the use of a serotonin receptor antagonist such as [[agomelatine]]. {{doi|10.1371/journal.pone.0082781}}

{{PMID|11526472}} 'significant excess of Ser allele carriers in patients compared to normal controls' (in 513 patients with recurrent MDD, 649 patients with bipolar affective disorder, and 901 normal controls)

{{omim
|desc=SEROTONIN 5-HT-2C RECEPTOR POLYMORPHISM
|id=312861
|rsnum=6318
|variant=0001
}}

{{PMID|20494452}} Further evidence supporting the association between 5HTR2C gene and bipolar disorder

== antipsychotics ==
{{PMID|19997080}} in a small sample of 45 autistic patients taking [[risperidone]] for up to one year, assoc. w/ prolactin elevation and BMI / waist circumference with [[risperidone]] usage

{{PMID|19193342}} [[rs6313]](T) (102T) allele of HTR2A, the [[rs5443]](T) (825T) allele of GNB3, the [[Rs6318]](G) (23Cys) allele of HTR2C, and the [[rs1801253]](C;C) (64Arg/Arg) genotype of ADRB3, were significantly associated with [[olanzapine]]-induced weight gain among 164 schizophrenic (per DSM-IV-TR) psychiatric inpatients

{{PMID|18332898}} no association with anti-psychotic induced weight gain noted in 104 Caucasian psychiatric inpatients 

{{PharmGKB
|RSID=rs6318
|Name_s=HTR2C:23Ser; HTR2C:Cys23Ser
|Gene_s=HTR2C
|Feature=Exon/NonSyn
|Evidence=PubMed ID:19193342
|Annotation=Ser in position 23 is associated with olanzapine-induced weight gain
|Drugs=olanzapine
|Drug Classes=
|Diseases=Weight gain
|Curation Level=Curated
|PharmGKB Accession ID=PA164889043
}}

{{PMID Auto
|PMID=20071033
|Title=Comorbidity between bipolar disorder and alcohol use disorder: Association of dopamine and serotonin gene polymorphisms
}}

{{PMID Auto
|PMID=20092861
|Title=Further exploration of the possible influence of polymorphisms in HTR2C and 5HTT on body weight
}}

{{PMID Auto
|PMID=20504252
|Title=Association of HTR2C, but not LEP or INSIG2, genes with antipsychotic-induced weight gain in a German sample
}}

{{PMID Auto
|PMID=18715570
|Title=Serotonin receptor HTR1A and HTR2C variants and personality traits in suicide attempters and controls
}}

{{PMID Auto
|PMID=21614492
|Title=A candidate gene study of serotonergic pathway genes and pain relief during treatment with escitalopram in patients with neuropathic pain shows significant association to serotonin receptor2C (HTR2C).
}}

{{PMID Auto
|PMID=21967853
|Title=Cortisol responses to emotional stress in men: association with a functional polymorphism in the 5HTR2C gene.
|OA=1
}}

{{PMID Auto
|PMID=22764241
|Title=Striatal Dopamine Release and Genetic Variation of the Serotonin 2C Receptor in Humans
|OA=1
}}

{{ClinVar
|rsid=6318
|Reversed=0
|FwdREF=G
|FwdALT=C
|REF=G
|ALT=C
|RSPOS=113965735
|CHROM=X
|GMAF=0.166365
|dbSNPBuildID=52
|SSR=0
|SAO=1
|VP=0x05017800000015051f110101
|GENEINFO=HTR2C:3358
|GENE_NAME=HTR2C
|GENE_ID=3358
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000023.10:g.113965735G>C
|CLNORIGIN=1
|CLNSIG=2
|Tags=PM;TPA;PMC;SLO;VLD;G5;HD;GNO;KGPhase1;KGPilot123;KGPROD;OTHERKG;PH3;LSD;OM
|CAF=0.8337; 0.1663
|CLNACC=RCV000010563.1
|CLNDBN=SEROTONIN 5-HT-2C RECEPTOR POLYMORPHISM
|CLNSRC=OMIM Allelic Variant
|CLNSRCID=312861.0001
|COMMON=1
|Disease=SEROTONIN 5-HT-2C RECEPTOR POLYMORPHISM
}}

{{PMID Auto
|PMID=17192951
|Title=HTR2C and HTR1A gene variants in German and Italian suicide attempters and completers.
}}

{{PMID Auto
|PMID=17964050
|Title=Lack of association between three serotonin genes and suicidal behavior in Chinese psychiatric patients.
}}

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

{{PMID Auto
|PMID=18802918
|Title=Focus on HTR2C: A possible suggestion for genetic studies of complex disorders.
}}

{{PMID Auto
|PMID=19032968
|Title=Serotonin genes and gene-gene interactions in borderline personality disorder in a matched case-control study.
}}

{{PMID Auto
|PMID=19359258
|Title=Cohort profile: risk patterns and processes for psychopathology emerging during adolescence: the ROOTS project.
|OA=1
}}

{{PMID Auto
|PMID=21162693
|Title=Pharmacogenetics and antipsychotics: therapeutic efficacy and side effects prediction.
|OA=1
}}

{{GET Evidence
|gene=HTR2C
|aa_change=Cys23Ser
|aa_change_short=C23S
|impact=pharmacogenetic
|qualified_impact=Insufficiently evaluated pharmacogenetic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs6318
|overall_frequency_n=2041
|overall_frequency_d=8761
|overall_frequency=0.232964
|n_genomes=23
|n_genomes_annotated=0
|n_haplomes=38
|n_articles=2
|n_articles_annotated=2
|qualityscore_in_silico=1
|qualitycomment_in_silico=Y
|in_omim=Y
|in_pharmgkb=Y
|pph2_score=0.004
|nblosum100=3
|autoscore=2
|webscore=N
}}

{{PMID Auto
|PMID=23221997
|Title=TPH1, MAOA, serotonin receptor 2A and 2C genes in citalopram response: possible effect in melancholic and psychotic depression
}}

{{PMID Auto
|PMID=24386118
|Title=A Functional Polymorphism in the 5HTR2C Gene Associated with Stress Responses Also Predicts Incident Cardiovascular Events
|OA=1
}}

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