Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as possible feature.

STUDY OBJECTIVES: McLeod syndrome (MLS) is a very rare multisystemic neurodegenerative disease linked to mutations in the XK gene. It has cardiac, neurologic, and neuromuscular manifestations and shares similarities with Huntington's disease. The aim of this study was to evaluate sleep patterns of patients affected by MLS.

METHODS: This retrospective case series of 4 males who underwent diagnostic polysomnography (mean age 53.8 ± 2.5 y) includes subjective and objective evaluation of sleep using the Epworth Sleepiness Scale (ESS), genetic tests, documentation of clinical course and features, and laboratory-based full-night attended video-polysomnography.

RESULTS: In three out of four patients, an ESS score ≥ 7 was evident. The average apnea-hypopnea index (AHI) was 45.0 ± 19.0, with predominantly obstructive phenotype (OSA) in 3 patients and predominant central events (central sleep apnea syndrome, CSAS) in one patient. A significantly increased periodic limb movement index (PLMI) during sleep was observed in all patients. All patients tolerated continuous positive airway pressure (CPAP) or Pressure Controlled (PC) therapy.

CONCLUSIONS: Polysomnography (PSG) of all patients confirmed sleep apnea syndrome (SAS) as a feature of MLS. Three patients were diagnosed with OSA and one with CSAS. In addition, PLMI was increased in all patients.