Hypersomnia in dystrophia myotonica: a neurophysiological and immunogenetic study

Abstract

Ten patients with dystrophia myotonica (8 adults and 2 prepubertal children), from three unrelated families, were investigated for diurnal sleepiness, using a sleep questionnaire and multiple sleep latency test (MSLT). Immunogenetic study was also carried out to assess the involvement of HLA region genes in modulating susceptibility to excessive diurnal sleepiness (EDS). EDS was reported by 5 patients and confirmed in each case by MSLT. In the whole patients group, mean daytime sleep latency was significantly shorter than in healthy controls matched for age and sex. At clinical or neurophysiological evaluation, EDS did not show the features associated with the narcoleptic type. In only one case hypersomnolence could be explained by underlying sleep-disordered breathing. HLA patterns were different from those frequently observed in the narcoleptic or non-narcoleptic types of hypersomnia. In patients with EDS, the frequency of the DQW1 and particularly of the DRW6-DQW1 haplotype appeared to be over-represented.

A polysomnographic study of daytime sleepiness in myotonic dystrophy type 1

“…Discrepancies in the quality of nocturnal sleep in DM1 have long been documented, with self-reports of either sleep disruption2 4 14 or deep, restorative sleep 5 15 16. Polysomnographic (PSG) studies yielded contradictory results, either showing indices of sleep fragmentation4 17 or normal sleep architecture features5 15 16 18 19 with8 – 10 or without15 17 sleep-onset rapid-eye movement (REM) periods (SOREMPs).…”

Daytime somnolence in myotonic dystrophy

“…However, the ptosis, myopathic facies and dysarthric speech noted in DM can give a false impression of somnolence, and therefore the true extent of the problem could be overestimated. A variety of factors including affective state, respiratory [8][9][10][11][12][13][14] and generalised skeletal muscle weakness, abnormalities in central and peripheral respiratory control [10,13,[15][16][17][18] and in arousal [19][20][21][22] might be associated with sleepiness in DM. Somnolence is recognised as a symptom which causes significant disability and handicap in the general population [23].…”

The Genetic Basis of Sleep Disorders

“…An intrinsic hypersomnia may therefore be associated sharing with narcolepsy a short sleep latency and the presence of sleep onset REM periods during the Multiple Sleep Latency Test. However, few studies revealed the absence of clear association between DM1 and HLA DQB1* 0602 as in narcolepsy but without any design to clearly establish an association between DMI with sleep-onset REM hypersomnia and HLA class II subtype [34]. A recent study noted the absence of difference between CSF hypocretin levels between 38 DM1 patients and 33 normal controls [36].…”

“…Amplification is frequently observed after parent-to-child transmission, but extreme amplifications are not transmitted through the male line. DM1 has long been recognized for its sleep disturbances, and excessive daytime sleepiness is the commonest complaint with multifactorial etiologies including sleep fragmentation, central and obstructive sleep apneas, and dysregulation of REM sleep with frequent abnormal REM sleep pressure [33,34]. An intrinsic hypersomnia may therefore be associated sharing with narcolepsy a short sleep latency and the presence of sleep onset REM periods during the Multiple Sleep Latency Test.…”