Respiratory dysfunction in Charcot-Marie-Tooth disease type 1A.

Area of Science:

• Neurology
• Respiratory Medicine
• Medical Imaging

Background:

• Charcot-Marie-Tooth disease type 1A (CMT1A) is a progressive peripheral neuropathy.
• Respiratory muscle weakness is a known complication, but its specific mechanisms and prevalence during sleep require further investigation.

Purpose of the Study:

• To investigate the relationship between neurological compromise, respiratory parameters (wakefulness and sleep), phrenic nerve physiology, and morphology in CMT1A patients.
• To correlate clinical disability scores with respiratory and nerve findings.

Main Methods:

• Evaluated 16 CMT1A patients using spirometry, maximal respiratory pressures (MIP, MEP), polysomnography, phrenic nerve compound muscle action potentials (CMAPs), and ultrasonography.
• Assessed clinical disability with the Charcot-Marie-Tooth neuropathy score (CMT-NS).
• Compared findings with 30 age- and sex-matched controls.

Main Results:

• CMT1A patients showed significantly higher apnea-hypopnea index (AHI) during sleep, particularly in REM sleep.
• Reduced maximal inspiratory and expiratory pressures (MIP, MEP) were common, correlating with higher CMT-NS.
• Phrenic nerves were enlarged on ultrasonography in all patients, correlating with CMAP values.
• AHI correlated negatively with MIP and MEP, and CMT-NS correlated positively with AHI.

Conclusions:

• Axonal degeneration of respiratory nerves likely contributes to respiratory weakness in CMT1A.
• Respiratory dysfunction, particularly sleep-related breathing abnormalities, is prevalent in CMT1A.
• Clinical manifestations of respiratory compromise are significant during sleep, potentially due to diaphragm overload.