Sleep disturbances in myotonic dystrophy type 2.

Area of Science:

• Neurology
• Sleep Medicine
• Genetic Disorders

Background:

• Sleep disorders are common in myotonic dystrophy type 1 (DM1).
• The prevalence and spectrum of sleep disturbances in myotonic dystrophy type 2 (DM2) are not well understood.
• DM2 is a genetic neuromuscular disorder with potential systemic effects.

Purpose of the Study:

• To investigate the occurrence and types of sleep disorders in patients with myotonic dystrophy type 2 (DM2).
• To assess the relationship between DM2 and common sleep disturbances like sleep-disordered breathing, hypersomnia, and fatigue.

Main Methods:

• Retrospective review of medical records for genetically confirmed DM2 patients seen at a sleep center (1997-2010).
• Data collected included demographics, laboratory results, overnight oximetry, and polysomnography (PSG).
• Pulmonary function testing was also analyzed for respiratory muscle weakness.

Main Results:

• Eight DM2 patients were identified, with 75% experiencing excessive daytime sleepiness and 62.5% reporting insomnia.
• Obstructive sleep apnea (OSA) was diagnosed in 60% of patients who underwent PSG.
• Respiratory muscle weakness was present in 100% of patients tested, and 50% met criteria for restless legs syndrome.

Conclusions:

• The clinical presentation of DM2 frequently includes a broad range of sleep disturbances.
• While respiratory muscle weakness is common in DM2, significant sleep-related hypoventilation was not observed in this cohort.
• Further prospective research is warranted to fully elucidate the scope of sleep issues in DM2.