title: Sleep cycling alternating pattern (CAP) expression is associated with hypersomnia and GH secretory pattern in Prader-Willi syndrome.
abstract: OBJECTIVE
  Hypersomnia, sleep-disordered breathing and narcoleptic traits such as rapid eye movement (REM) sleep onset periods (SOREMPs) have been reported in Prader-Willi syndrome (PWS). In a group of young adult patients with genetically confirmed PWS we evaluated sleep and breathing polysomnographically, including cycling alternating pattern (CAP), and we analyzed the potential interacting role of sleep variables, sleep-related breathing abnormalities, hypersomnia, severity of illness variables and growth hormone (GH) secretory pattern.
  
  
  METHODS
  Eleven males and 7 females (mean age: 27.5+/-5.5 years) were submitted to a full night of complete polysomnography and the multiple sleep latency test (MSLT). GH secretory pattern was evaluated by a standard GH-releasing hormone plus arginine test. Sixteen non-obese healthy subjects without sleep disturbances were recruited as controls.
  
  
  RESULTS
  Compared to controls PWS patients showed reduced mean MSLT score (P<0.001), reduced mean latency of sleep (P=0.03), increased REM sleep periods (P=0.01), and increased mean CAP rate/non-rapid eye movement (NREM) (P<0.001). Only four PWS patients had apnea/hypopnea index (AHI)>or=10. Conversely, significant nocturnal oxygen desaturation was frequent (83% of patients) and independent from apneas or hypopneas. In the PWS group, CAP rate/NREM showed a significant negative correlation with MSLT score (P=0.02) independently from arousals, respiratory disturbance variables, severity of illness measured by Holm's score or body mass index (BMI). PWS patients with CAP expression characterized by higher proportion of A1 subtypes presented less severe GH deficiency (P=0.01).
  
  
  CONCLUSIONS
  Our study suggests a relationship between hypersomnia and CAP rate, and between CAP expression and GH secretory pattern in PWS, possibly reflecting underlying central dysfunctions.
authors.affiliation: Divisione di Neurologia e Neuroriabilitazione, Department of Neurology, IRCCS Istituto Auxologico Italiano, Ospedale S.Giuseppe, Casella postale 1, Intra, 28921 Piancavallo (VB), Verbania, Italy. l.priano@auxologico.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Priano
authors.forename: Graziano
authors.initials: G
authors.lastname: Grugni
authors.forename: Giacinta
authors.initials: G
authors.lastname: Miscio
authors.forename: Giulia
authors.initials: G
authors.lastname: Guastamacchia
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Toffolet
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sartorio
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mauro
mesh_terms: D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology; D016022:Case-Control Studies; D006970:Disorders of Excessive Somnolence / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D019382:Human Growth Hormone / Q000096:biosynthesis*; D006801:Humans; D008297:Male; D017286:Polysomnography; D011218:Prader-Willi Syndrome / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology*; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology
chemical_list: D019382:Human Growth Hormone