Inaugural Patient-Reported Registry of Pediatric Opsoclonus-Myoclonus-ataxia Syndrome: Presentation, Diagnosis and Treatment of 194 Patients

Background Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare neuroimmune disease with peak onset at 18 months, associated with neural crest tumors in 50% of patients. In part due to its rarity, misdiagnosis at onset is common, can delay treatment, and may contribute to adverse outcomes. Small sample sizes often limit clinician-driven, single-site studies of rare diseases. Patient-reported registries may overcome some of these challenges in rare disease research. In this context, the OMSLife Foundation collaborated with the National Organization of Rare Diseases to create a patient-reported registry in OMAS. Methods Retrospective analysis of data entered by OMAS patients’ parents into 9 online surveys assessing demographics, symptoms at onset, triggers, time of diagnosis, treatment, and additional therapies. Results A total of 194 patients were enrolled. There was a female predominance (54%) and high rate of parental autoimmunity (31%). Age at onset peaked between 12 and 18 months overall. The age of onset was older in female patients (median [interquartile range]: females 22 [15-31] vs. males 18 [14-23], p=0.0223, p=0.0223). Symptoms at onset most commonly included ataxia (84%) and were typically severe. Initial misdiagnosis occurred in nearly 50% and tumor discovery was delayed in 18 patients, but overall median time to correct diagnosis was 25 days. Most patients (56%) received combination immunomodulatory therapies and nearly all underwent supportive therapies. Conclusions Patient and parent-powered research is feasible in OMAS and created the second largest published cohort of pediatric OMAS patients. Results were similar to other large cohorts and also validated findings from prior case reports and smaller case series.