Association analysis between a Cys23Ser substitution polymorphism of the human 5-HT2c receptor gene and neuronal hyperexcitability

Transgenic mice lacking a functional 5-HT2c receptor gene are extremely susceptible to audiogenic seizures, suggesting that 5-HT2c receptors mediate inhibition of neuronal network excitability. The present association study tested the hypothesis that a Cys23Ser substitution polymorphism within the human 5-HT2c receptor gene modulates neuronal excitability. Genotypes of the Cys23Ser polymorphism were assessed in 454 subjects of German descent, comprising: 1) 93 severely affected alcohol-dependent males with a history of alcohol withdrawal seizure or delirium, 2) 119 patients affected by an idiopathic generalized epilepsy, and 3) 242 controls. Both sexes were analyzed separately because of the X-chromosomal location of the 5-HT2c receptor gene. The allele frequencies of the Cys23Ser variants did not differ significantly between the controls and either the severely affected alcohol-dependent males (P = 0.34), or patients with idiopathic generalized epilepsy (P > 0.57). Our results suggest that the common Cys23Ser substitution polymorphism of the human 5-HT2c receptor gene does not confer susceptibility to neuronal hyperexcitability in either idiopathic generalized epilepsy or alcohol withdrawal seizure or delirium.