Platelet serotonin transporters and the transporter gene in control subjects, unipolar patients and bipolar patients

Objective: The purpose of the present study was to relate the number of pla telet serotonin transporters in unipolar and bipolar patients and in contro l subjects to two polymorphisms in the serotonin transporter gene: a VNTR i n intron 2 and a deletion/insertion in the promoter region. Method: Density of platelet serotonin transporters was determined by radiol igand binding analysis. Genotyping was performed by PCR amplification of po lymorphic regions followed by size determination of the obtained fragments. Results: The control subjects and the two groups of patients were similar w ith respect to the genotype and allele distribution belonging to the two po lymorphisms in the serotonin transporter gene for. An interaction between s tatus (control, unipolar- or bipolar patient) and VNTR genotype regarding t he number of platelet serotonin transporters was observed; unipolar patient s with the genotype 12/10 had more platelet serotonin transporters than bip olar patients and controls with this genotype. No association related to th e polymorphism was found in the promoter region of the serotonin transporte r gene. Conclusion: An association was observed between the polymorphism in intron 2 of the serotonin transporter gene and the number of platelet serotonin tr ansporters. Unipolar patients with a particular genotype had more platelet serotonin transporters than the corresponding controls and bipolar patients .