Novel 5′-regulatory region polymorphisms of the 5-HT2C receptor gene: association study with panic disorder

Abstract

Candidate genes for association studies in panic disorder are often selected on the basis of molecular mechanisms of drugs utilized in challenge tests such as m-chlorophenylpiperazine (mCPP), a non-selective 5-HT2C receptor agonist. Two novel, adjacent polymorphisms [(GT)12-18 and (CT)4-5] in the 5'-regulatory region of the X-chromosomal 5-HT2C receptor gene have recently been reported. We determined the allele frequency of long vs. short polymorphism haplotypes in a German and an Italian sample (combined n = 211) of panic disorder patients (DSM-III-R) and compared it with allele frequencies in two ethnically matched control samples (combined n = 226). In the German sample, a comparison of female genotypes containing the short haplotype vs. female genotypes containing only long haplotypes showed a significant difference (p = 0.01, ?2 analysis). In the Italian sample, however, this observation could not be replicated (p = 0.54, ?2 analysis). This argues against a major role for these promoter-associated 5-HT2C receptor gene length polymorphisms in the aetiopathogenesis of panic disorder.