Serotonin transporter gene (5HTT) polymorphisms and temporal lobe epilepsy.

OBJECTIVE: Preclinical and clinical studies have shown that serotonin levels might modulate susceptibility to seizures. Here we evaluated an association between 5HTTLPR and 5HTTVNTR allele variants in serotonin transporter gene and epileptogenesis in temporal lobe epilepsy (TLE). METHODS: A case-control candidate gene study evaluating the frequencies of 5HTTLPR biallelic and 5HTTVNTR allele variants in patients and healthy subjects. Genotypes were grouped according to transcriptional efficiency. Cases were 175 patients with TLE selected from the Epilepsy Outpatient Clinic of Hospital de Clínicas de Porto Alegre, classified according to the electroclinical classification of the ILAE and neuroimaging findings. The control group consisted of 155 healthy unrelated subjects selected from the same population. RESULTS: We observed that less efficient transcriptional genotypes for 5-HTT polymorphisms were more frequent in epileptic patients (O.R.=3.24; 95% C.I.=1.08-9.73; p=0.036). Our results suggest that less efficient transcriptional genotypes for serotonin transporter gene are associated with TLE. CONCLUSION: In this study we observed an association between the presence of 5HTTLPR and 5-HTTVNTR less transcriptional efficient combined genotypes and TLE. Our results suggest that modulation of the serotoninergic system might be implied in epileptogenesis in TLE.