Relapsing Neuromyelitis Optica: demographic and clinical features in Iranian patients

Background: Neuromyelitis Optica (NMO) is a severe inflammatory demyelinating disease of the central nervous system with distinguishing features from multiple sclerosis (MS). NMO has an unknown etiology with poor prognosis in which anti-aquaporin-4 receptor IgG seems to play a major role. The purpose of this study is to represent a clinical and demographic data of NMO in Iranian population. Methods: Of 1800 patients attending our MS clinic, 44 patients with NMO were recruited from 2006 to 2009. Results: Female to male ratio was 3:1 and the disease affected women in younger ages than men (P = 0.04). The median expanded disability status scale score was 3 and the mean duration of symptoms was 4.53 +/- 3.41 (median = 4) years with annual relapse rate of 1.13 year/patient. The most frequent symptoms at presentation were optic neuritis 22 (50%) and transverse myelitis 14 (31.8%). Out of 12 patients whose titer of NMO-IgG was measured, four (30.7%) patients were seropositive. Twenty-eight patients (63%) received azathioprine for a mean duration of 16.84 +/- 27.91 months with significantly lower annual relapse rate (0.4 year/patient). Conclusions: Iranian patients as a Caucasian population living in Asia seem to have the same clinical features in comparison with the reported studies from Western countries. Although the duration of follow-up was not too long, but they may possibly have a more benign course.