Sleep pattern in Charcot-Marie-Tooth disease type 2: report of family case series

Charcot-Marie-Tooth (CMT) disease is the most prevalent hereditary motor and sensory polyneuropathy, and a condition in which sleep has rarely been studied, particularly in relation to the type 2 (CMT2). Thus, we aimed to characterize the sleep patterns of a family affected by CMT2 disease.

Sixteen volunteers with CMT2 from the same multigenerational family agreed to participate in the study (refusal rate = 31%). All participants answered sleep questionnaires and came to the sleep laboratory to perform a diagnostic polysomnography (PSG). Clinical manifestation and severity of the disease were also evaluated.

56% of the sample were male and 44% female, with a mean age of 32 ± 17 years, of normal weight (body mass index 21 ± 3 kg/m(2)); 64% presented moderate to severe CMT2. Regarding subjective sleep, 31% had excessive daytime sleepiness and 75% reported poor sleep quality. The PSG results revealed that CMT2 patients had an increase in stage N3 and a reduction in REM sleep, in addition to a high arousal index. Although 81% of the sample were snorers, only 13% had an apnea-hypopnea index (AHI) > 5. However, a positive correlation was found between the severity of disease and the AHI.

Taken together, these data show that CMT2 disease is characterized by important changes in sleep architecture, probably due to sleep fragmentation. Although these alterations may worsen with disease severity, it seems that they are not related to sleep breathing or movement disorders.