Postural orthostatic tachycardia syndrome due to NET deficiency

A rare, genetic, primary orthostatic disorder caused by the impaired clearance of neurotransmitters at the synaptic cleft due to the deficiency of norepinephrine transporters (NET), characterized by dizziness, palpitations, fatigue, blurred vision and tachycardia following postural change from a supine to an upright position, in the absence of hypotension. A syncope with transient cognitive impairment and dyspnea may also occur. The norepinephrine transporter deficiency leads to abnormal uptake and high plasma concentrations of norepinephrine.