From PNS to CNS: characteristics of anti-neurofascin 186 neuropathy in 16 cases.

Introduction Neurofascin (NF) is critical for the formation and maintenance of Ranvier nodes. NF186, the neuronal form of NF, localizes in the initial segment of axon and Ranvier node. NF186 antibody has been detected in demyelinating diseases of both central nervous system (CNS) and peripheral nervous system (PNS). Aims To evaluate the clinical features of patients with anti-NF186 IgG neuropathy. Methods Sixteen patients (16/138) with serum-positive anti-NF186 IgG were included and divided into groups of either CNS or PNS-involved according to their clinical manifestations. Anti-NF186 IgG was detected by cell-based assays. Results In 7 patients who were confirmed to have CNS involvement, the most frequent symptoms were dizziness (57%) and vision impairment (43%); lesions in centrum semiovale, cerebellum, and meninges were shown by magnetic resonance imaging (MRI). In comparison, limb weakness (78%) and numbness (78%) were the most common symptoms in PNS-involved patients; axonal loss and demyelination were confirmed by nerve conduction examinations. Elevated level of cerebrospinal fluid (CSF) protein was found in 12 cases without statistically significant difference between the CNS and PNS groups. Meanwhile, CSF white blood cell counts were found significantly elevated in CNS-involved patients compared with patients of PNS group. Thirteen patients received immunomodulating treatments, and patients with chronic onset and progressive course showed poor response to the therapies. Conclusions Patients with anti-NF186 IgG neuropathy showed no specific symptoms or signs. It is worth noting that quite a few patients show CNS-impaired signs only, and cranial MRI is essential for the screening of CNS involvement.