title: Periodic limb movement in sleep in children with Williams syndrome.
abstract: OBJECTIVE
  Williams syndrome (WS) is associated with neurobehavioral abnormalities that include irritability and attention-deficit/hyperactivity disorder. Parents often report children having difficulties initiating and maintaining sleep because of restlessness and arousals. Therefore we evaluated a group of children with WS for the presence of a movement arousal sleep disorder.
  
  
  METHODS
  Twenty-eight families of children with WS participated in a telephone survey aimed to screen for a movement arousal disorder. Of the 16 children identified as having such a disorder, 7 (mean age, 3.9 +/- 2.2 years) underwent polysomnography. Their studies were compared with those of 10 matched control subjects (mean age, 5.3 +/- 2.0 years).
  
  
  RESULTS
  The 7 subjects with WS who were screened by the survey had sleep latency, total sleep time, arousals, and awakenings that were similar to those of control subjects. However, they presented with a disorder of periodic limb movement in sleep (PLMS). The PLMS index in the subjects with WS was 14.9 +/- 6.2 versus 2.8 +/- 1.9 in control subjects (P < .0001). In addition, arousal and awakening in subjects with WS were strongly associated with PLMS. Moreover, children with WS spend more time awake during sleep periods than control subjects (10.0% +/- 7.0% vs 4.4% +/- 4.7%; P < .05). Five children were treated with clonazepam, and in 4 a significant clinical response was noted.
  
  
  CONCLUSIONS
  We report an association between WS and PLMS. Clonazepam may reduce the clinical symptoms of PLMS in some of these children.
authors.affiliation: Division of Pulmonary Medicine, Children's Hospital of Philadelphia, PA 19104-4399, USA.
authors.forename: R
authors.initials: R
authors.lastname: Arens
authors.forename: B
authors.initials: B
authors.lastname: Wright
authors.forename: J
authors.initials: J
authors.lastname: Elliott
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.forename: P P
authors.initials: PP
authors.lastname: Wang
authors.forename: L W
authors.initials: LW
authors.lastname: Brown
authors.forename: T
authors.initials: T
authors.lastname: Namey
authors.forename: P
authors.initials: P
authors.lastname: Kaplan
mesh_terms: D000927:Anticonvulsants / Q000008:administration & dosage; D001143:Arousal / Q000187:drug effects / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D002998:Clonazepam / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D017286:Polysomnography; D012148:Restless Legs Syndrome / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology; D018980:Williams Syndrome / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics
chemical_list: D000927:Anticonvulsants; D002998:Clonazepam