We previously defined a subgroup of POTS patients in whom we detected a partial peripheral autonomic neuropathy primarily affecting lower extremities (neuropathic POTS). These subjects had decreased norepinephrine spillover in response to sympathetic activation and abnormal sweat volumes and prolonged latency detected by quantitative sudomotor axon reflex (QSART). Recently, Gibbons and Freeman (2013) strengthen the definition by providing histological evidence of neuronal damage with the inclusion of skin biopsies with specific staining for autonomic dense fiber and sensitivity assessment.