SLC6A2, also known as NET, is a norepinephrine (noradrenaline) transporter, which regulates norepinephrine homeostasis by reuptaking the norepinephrine released into synaptic cleft in Na+- and Cl-- dependent manner. Mutation of the SLC6A2 gene can cause orthostatic intolerance, which is characterized by lightheadedness, fatigue, altered mental condition, and syncope. Drugs inhibiting the norepinephrine transporter such as antidepressants, cocaine, and amphetamines also lead to symptoms like orthostatic intolerance.