Tongue tremor in neurofascin-155 IgG4 seropositive chronic inflammatory polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with anti-neurofascin-155 antibodies is a subgroup of CIDP with tremor and poor response to intravenous immunoglobulins. A 23-year-old male presented with a 6-month history ataxic-stepping gait, stocking tactile hypoesthesia, areflexia, tremor at limbs and tongue. Neurophysiology and cerebrospinal fluid analysis supported the diagnosis of CIDP. Tongue EMG was negative. Serum was positive for neurofascin-155 IgG4. His symptoms improved with intravenous methylprednisolone and then immunoglobulins, but not the tremor. Neurofascin-155 antibodies binding to cerebellar neurons suggests its central origin. This is the first neurofascin-155 antibody-seropositive patient with also tongue tremor, who is candidate to rituximab.