RESUMO
The association between the serotonin transporter gene (SLC6A4) polymorphisms, that is, 5-HTTLPR and rs25531, and Parkinson's disease (PD) remains to be further defined. We investigated this relationship in a Chinese cohort that comprised 504 PD patients and 504 controls. A total of 8 haplotypes and 14 genotypes of SLC6A4 were found in this population including a new variant of 5-HTTLPR, that is, 20G. Our results presented that 5-HTTLPR was associated with an aggravated risk for PD (p = 0.005). The rs25531 alone is not associated with PD susceptibility. However, in a sub-classification based on the impact of 5-HTTLPR and rs25531 on 5-HTT expression, we observed a significant difference in 5-HTT expressing distribution in the cohort, accompanied by an apparently lower level of 5-HTT high expressing group, that is, the LALA genotype, in the PD patients. Taken together, our data provide novel insight in support that the SLC6A4 polymorphisms, particularly 5-HTTLPR, and the serotonergic system are associated with PD etiology.