Methylation of another neurotransmitter transporter, noradrenaline transporter (NET), also known as solute carrier family 6, member 2 (SLC6A2), was also studied in subjects with PD and hypertension; results showed that DNA hypermethylation in the promoter region of NET caused NET gene silencing through the binding of methyl-CpG binding protein 2 (MeCP2), a methylation-related inhibitory transcription factor [20, 21]. Here, SLC6A2 is linked to hypertensive disorder.