An association between serotonin receptor 3B gene (HTR3B) and treatment-resistant schizophrenia (TRS) in a Japanese population.

Genetic factors are thought to be involved in the development of treatment-resistant schizophrenia (TRS). Since several antipsychotic drugs inhibit the release of neurotransmitters via the serotonin receptors 3 (5-HT3), a dysfunction of this kind of receptor might be associated with the development of TRS. Thus, single-marker and haplotype analyses of the tag-single nucleotide polymorphisms (SNPs) of the 5-HT3B subunit gene (HTR3B) were performed in TRS (n = 101) and non-TRS (n = 244) patients. The deletion allele at the 3 bp-insertion/deletion polymorphism site (-100_-102delAAG) located in the putative HTR3B promoter region is significantly more frequent in the TRS group than the insertion allele by a single-marker comparison (p = 0.031). In addition, luciferase promoter assays showed that the deletion allele exhibited significantly higher transcriptional activity than the insertion allele in COS7 cells (p < 0.05). These results suggest that HTR3B is involved in the development of TRS in the Japanese population.