Juvenile Myasthenia Gravis in North Texas: Clinical Features, Treatment Response, and Outcomes

Background Juvenile myasthenia gravis (JMG) is a rare autoimmune disease that causes fatigable muscle weakness in children ages <18 years. There is currently no curative treatment or internationally accepted standard of care for JMG. The objective is to investigate relationships between clinical presentation, antibody status, severity of disease onset, electrodiagnostic evaluation and response to therapy in JMG. Methods This study was a retrospective chart review. Congenital myasthenic syndromes were excluded. Data on demographics, treatments, and outcomes were collected. Disease severity was evaluated using Myasthenia Gravis Foundation of America (MGFA) clinical classifications. Results We identified 84 JMG patients at Children's Medical Center Dallas between January 2014 and February 2022. 52% of patients presented with ocular JMG (median onset age 4.5 years) and 48% generalized JMG (median onset age 11.5 years). 81% tested positive for acetylcholine receptor antibodies. Patients were 17% non-Hispanic White, 29% Hispanic, 39% Black, 12% Asian. There was a significant difference in average MGFA scores between ethnicities (p=0.047) and age groups (p=0.004), with post-pubertal patients having higher average MGFA scores than pre-pubertal patients. 71% of patients who underwent thymectomy experienced a decrease in MGFA scores post-procedure. Conclusion Our study showed that there were significant differences in disease severity between ethnicities and age groups, and most patients who underwent thymectomy showed clinical improvement. These outcomes highlight the need for additional therapies in the treatment of JMG and the importance of extending clinical trials to the pediatric population.