No association between polymorphism of serotonin transporter gene and depression in Parkinson's disease in Chinese

Depressive symptoms affect 40% to 50% of Parkinson's disease (PD) patients, and adversely impact their quality of life. The decrease of serotonin (5-HT) in the synaptic cleft is commonly considered as the cause of depression. The reuptake of 5-HT released into the synaptic cleft is mediated by the 5-HT transporter (5-HTT). Many studies have focused on the relationship between the 5-HTT-linked polymorphic region (5-HTTLPR) and depression. The present study is to investigate the association between the polymorphisms in the promoter of the 5-HTT gene (including 5-HTTLPR and rs25531), which determine either a higher or lower 5-HT uptake, and risk for depression of PD. Three hundred six idiopathic PD patients were recruited randomly from hospital clinic and the Center for Epidemiological Studies Depression Scale (CES-D) was used as the diagnosis or rating scale for depression. Polymerase Chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used and the patients’ genotypes were divided as LA, LG, SA, and SG. We found no evidence for an association between variants of 5-HTTLPR and rs25531 alleles, and depressive symptoms in Chinese PD patients.