No association between the serotonin transporter-linked promoter region polymorphism and either schizophrenia or density of the serotonin transporter in human hippocampus

Abstract

Background: Allelic association case-control analysis of a deletion/insertion polymorphism in the serotonin transporter-linked polymorphic region (5-HTTLPR) has suggested associations with unipolar disorder, bipolar disorder, depression, and Alzheimer's disease. Moreover, the heterozygous long form of the 5-HTTLPR has been associated with increased levels of mRNA for the serotonin transporter (5-HTT) and increased serotonin uptake in lymphoblastic cell lines. This study attempts to determine whether there is an association between 5-HTTLPR genotype and schizophrenia or the binding of [3H]paroxetine to the human hippocampal 5-HTT. Materials and Methods: DNA from the cerebellum from 58 schizophrenic and 62 control subjects was used to genotype the 5-HTTLPR. In addition, the relationship between 5-HTTLPR genotype and the affinity and density of [3H]paroxetine binding to the hippocampal 5-HTT was assessed. Results: There were no associations between 5-HTTLPR allotype or genotype and/or the parameters of [3H]paroxetine binding to the hippocampal 5-HTT. Conclusions: Our data suggest that 5-HTTLPR genotype neither confers an increased susceptibility for schizophrenia nor dictates the expression of the 5-HTT in the human hippocampus.