The serotonin transporter gene and Parkinson's disease

Dysfunction in the serotonin (5-hydroxytryptamine) system and reduced serot onin concentrations have been reported in patients with Parkinson's disease (PD). Serotonin concentrations in neural tissue are controlled by a presyn aptic serotonin transporter protein that is encoded by a single gene. There fore, we investigated whether a polymorphic region in the serotonin transpo rter gene is associated with PD. Three variable-number tandem repeat (VNTR) elements of the serotonin transporter gene were detected by polymerase cha in reaction, those with 9, 10, 11 and 12 copies of the repeat element. The 10-copy VNTR element was significantly less common in patients with PD than controls in the univariate analysis (p < 0.05). Logistic regression analys is revealed no significant differences between patients (n = 198) and contr ols (n = 200) in the distribution frequencies of 9-and 12-copy alleles and combined genotypes (odds ratio = 1.20; p = 1.71). A positive family history of PD was a strong predictor of disease risk (odds ratio = 2.98; 95% confi dence interval 1.51-5.87; p = 0.001). Although slight differences were obse rved between patient and control groups, these data suggest that defects in serotonin concentrations in patients with PD are unlikely to be due to pol ymorphisms in the serotonin transporter gene in this large Australian cohor t; however, the inverse association observed with the 10-copy allele warran ts further investigation. Copyright (C) 2000 S. Karger AG, Basel.