Sleep disorders in patients with myasthenia gravis based on antibody subtypes: a polysomnographic study.

BACKGROUND: Sleep-disordered breathing (SDB) is increasingly recognized in myasthenia gravis (MG), yet potential differences in sleep respiratory patterns between antibody-defined MG subtypes remain poorly understood. We aimed to evaluate sleep disorders and polysomnographic characteristics in patients with acetylcholine receptor antibody–positive (AChR-MG) and muscle-specific tyrosine kinase antibody–positive (MuSK-MG) generalized MG. METHODS: Eighteen clinically stable MG patients (9 AChR-MG, 9 MuSK-MG) and 9 healthy controls underwent attended overnight polysomnography followed by the Multiple Sleep Latency Test (MSLT). Standardized sleep questionnaires and MG clinical scales were administered to assess sleep-related symptoms and disease severity. RESULTS: Obstructive sleep apnea was detected in 89% of AChR-MG and 78% of MuSK-MG patients. Both MG subgroups showed significantly higher apnea–hypopnea index values compared with controls (p < 0.05). Although overall AHI severity did not differ significantly between antibody groups, distinct respiratory patterns were observed. Respiratory events clustered predominantly during REM sleep in AChR-MG, whereas MuSK-MG patients exhibited more frequent events during NREM or supine sleep. CONCLUSIONS: Sleep-disordered breathing appears to be common in MG, but polysomnographic patterns may differ according to antibody subtype. REM-predominant respiratory events in AChR-MG and NREM or positional predominance in MuSK-MG may reflect differences in muscle involvement between these subtypes. These findings suggest that antibody-specific mechanisms may influence nocturnal respiratory dysfunction in MG and highlight the importance of targeted sleep assessment in this population.