The nicotinic acetylcholine receptor (nAChR) antibody directly contributes to the autonomic dysfunction in Autoimmune Autonomic Ganglionopathy (AAG). The pathological mechanism leading to autonomic dysfunction in seronegative AAG is unclear. We evaluated patients with presumed antibody negative AAG (n=49) to determine whether there was an association with other autoantibodies. Three patients met the clinical criteria and were positive for N-type calcium channel antibodies. All patients had severe autonomic dysfunction characterized by orthostatic hypotension and gastrointestinal involvement. Autonomic testing revealed severe impairment of sudomotor, cardiovagal, and adrenergic domains. These findings raise the possibility that other autoantibodies may contribute to the pathogenesis of AAG.