Serotonin and dopamine transporter genes do not influence depression in Parkinson's disease

Abstract

Altered levels of the neurotransmitters dopamine and serotonin are observed in both Parkinson's disease (PD) and depression. Therefore, the neurotransmitter transporter genes, SLC6A3 (dopamine) and SLC6A4 (serotonin) are candidates for depression in PD. We genotyped 24 tagging SNPs together with VNTRs and the SLC6A4 LPR polymorphism in 190 PD patients categorised according to lifetime history of depression. Log-additive, dominant and recessive statistical models were constructed. No significant genotype or haplotype associations were observed suggesting that common genetic variables around the dopamine and serotonin transporter genes do not play a significant role in the etiology of depression in PD.