Gastrointestinal motility disorders represent a heterogeneous group of neuromuscular diseases of the enteric nervous systems. While autoimmune neuromuscular diseases of the central nervous system (CNS) are well described, the role of autoimmunity in enteric nervous system (ENS) has been less studied. Approximately 10% of patients with unexplained gastrointestinal dysmotility diseases have positive serum autoantibodies to peripheral nervous system proteins, suggesting an autoimmune mechanism targeting the enteric nervous system. The investigator's aim is to identify novel anti neuronal antibodies that contribute to autoimmune gastrointestinal motility disorders by analyzing the serum of patients with abnormal gastrointestinal motility.