Association between clozapine response and allelic variation in the 5-HT2C receptor gene

Neuroreport. 1995 Dec 29;7(1):169-72.


A cysteine to serine substitution at amino acid 23 in the 5-HT2C receptor gene alters the pharmacological properties of the protein. We investigated this polymorphism in subjects with schizophrenia resistant to conventional neuroleptic drugs, and analysed our data for allelic association between the disease state or clinical response to the atypical antipsychotic drug, clozapine. Ninety percent of subjects who had one or more 5-HT2Cser alleles (19/21) were classified as clozapine responders compared with 59% (84/141) without this allele (chi 2 = 7.7, p = 0.005), suggesting that this mutation is a predictor of good response to clozapine. There was no association between schizophrenia and the 5-HT2Cser allele, but our results indicate that the 5-HT2C receptor may contain the major site of action through which clozapine mediates its antipsychotic effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Antipsychotic Agents / therapeutic use*
  • Base Sequence
  • Case-Control Studies
  • Clozapine / therapeutic use*
  • Double-Blind Method
  • Genetic Variation*
  • Genotype
  • Humans
  • Molecular Sequence Data
  • Polymorphism, Genetic
  • Prognosis
  • Receptors, Serotonin / genetics*
  • Schizophrenia / drug therapy*
  • Schizophrenia / genetics
  • Serotonin Antagonists / therapeutic use*
  • Treatment Outcome


  • Antipsychotic Agents
  • Receptors, Serotonin
  • Serotonin Antagonists
  • Clozapine