Characteristics of Neuromyelitis Optica in Young Mexican Patients

Background: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disease with important disability accumulation. Early-onset NMOSD, defined as disease onset before age 50, exhibits distinct clinical characteristics compared to late-onset disease. We present a case series of patients with first symptom onset before age 30. Methods: Retrospective review of 10 patients diagnosed with NMOSD at our center in San Luis Potosí, Mexico, with disease onset before age 30. Clinical presentation, imaging findings, AQP4 antibody status, treatment response, and disability outcomes were analyzed. Results: Mean age at onset was 18.6 years (range 6-30). Area postrema syndrome was the most common presentation (40%), followed by acute myelitis and optic neuritis (30% each). All tested patients were AQP4-positive. Mean EDSS at follow-up was 6.6, indicating severe disability. Most patients received rituximab with variable response rates. Conclusions: Our cohort showed higher disability than reported in other early-onset series, emphasizing the need for prompt diagnosis and aggressive treatment in this population.