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Background and purpose: Double‐seronegative myasthenia gravis (dSNMG) is defined as myasthenia gravis (MG) without detectable or low affinity antibodies to acetylcholine receptor (AChR) and muscle‐specific kinase (MuSK). There are limited data on detailed clinical features and outcomes after treatment in dSNMG patients. The aim was to describe the clinical characteristics and outcomes in dSNMG patients based on MG scales. Methods: A retrospective study was performed of patients diagnosed with MG who had negative AChR or MuSK antibodies and they were compared with an AChR‐positive MG cohort. Correlations were made with data from the first and last clinic visits, between demographics, clinical characteristics, treatment and disease severity, based on the Myasthenia Gravis Foundation of America category, Myasthenia Gravis Impairment Index (MGII), Patient Acceptable Symptom State and simple single question (SSQ). Results: Eighty patients met the inclusion criteria for dSNMG. The baseline MGII and SSQ scores in the dSNMG cohort showed no significant differences from the AChR group (p = 0.94 and p = 0.46). The dSNMG cohort MGII and SSQ scores improved significantly at the last clinical evaluation (p = 0.001 and p = 0.047). The MGII improvement in the AChR cohort was significantly better (p = 0.003). Conclusions: The initial severity of dSNMG based on clinical scores is similar to antibody‐positive MG patients. There is significant clinical improvement in dSNMG patients after therapy, measured in the last clinical evaluation. This supports an immune pathophysiology of many dSNMG patients. [ABSTRACT FROM AUTHOR]

This document is a reply to a letter in response to a previously published article titled "Clinical Characteristics and Treatment Outcomes in Patients with Double-Seronegative Myasthenia Gravis." The authors of the reply express gratitude for the comments and acknowledge the importance of further discussion on the topic of patients without detectable antibodies to nicotinic acetylcholine receptor (AChR) and muscle-specific kinase. They agree with the suggestion that electrophysiological findings and complementary diagnostic tests should be considered in the diagnosis of myasthenia gravis (MG). The authors also highlight the need for further characterization of serological markers in seronegative MG patients and the potential role of novel antibodies in the disease. They conclude that dSNMG patients show significant clinical improvement after treatment, supporting an immune-mediated pathophysiology, and emphasize the importance of developing new biomarkers for personalized clinical characterization and individualized therapeutic approaches. [Extracted from the article]

There is a pressing need for a robust rating scale for ocular myasthenia gravis (OMG). Rating scales for myasthenia gravis (MG) research have a predominant focus on generalised disease. We present results of the first dedicated rating scale for OMG: the ocular myasthenia gravis rating scale (OMGRate). The OMGRate was developed through an international collaboration between neuromuscular and neuro-ophthalmology experts in OMG. It comprises two components: a physician- examination (OMGRate-e) and a patient questionnaire (OMGRate-q).. The OMGRate was prospectively validated in patients attending a neuro-ophthalmology clinic from April 2017 to October 2018. External validity and reliability of OMGRate were evaluated using validated MG rating scales: the Myasthenia Gravis Composite (MGC), the Myasthenia Gravis Quality of Life (MG-QOL), and the ocular component from the Myasthenia Gravis Impairment Index questionnaire (MGII). Two hundred and eleven assessments were completed in 104 patients (67 males, mean age 55 y, range 18–86 y). There was very good external validity of the OMGRate: good correlation between OMGRate-e and MGC (r = 0.64, 95% confidence intervals [CI] 0.54–0.74, p <.0001); excellent correlation between OMGRate-q and MGII (r = 0.85, 95% CI 0.78–0.91, p <.0001) and good correlation between OMGRate and MG-QOL (r = 0.68, 95% CI 0.60–0.77, p <.0001). A higher correlation of OMGRate and MG-QOL compared with MGC and MG-QOL (r = 0.47, 95% CI 0.34–0.59, p <.0001) suggests that OMGRate is better able to capture significant QOL information in patients with OMG. It had excellent reliability with an intraclass correlation coefficient of 0.83 (95% CI 0.67–0.92). Feedback from examiners and patients indicated that the OMGRate was easy to use. In conclusion, OMGRate is an easy-to-use, valid and reliable rating scale for monitoring the severity of OMG. [ABSTRACT FROM AUTHOR]