title: Stimulus-induced myoclonus treated effectively with clonazepam in genetically confirmed Coffin-Lowry syndrome.
abstract: OBJECTIVE
  Coffin-Lowry syndrome (CLS) is a rare X-linked semidominant syndromic genetic disorder that is characterized by typical facial and radiologic findings, psychomotor and growth retardation, and various skeletal anomalies. A distinctive paroxysmal disorder called stimulus-bound myoclonus is clinically heterogeneous and is generally characterized by a sudden loss of muscle tone that is regained within a few seconds and is induced by sudden auditory or tactile stimulus. As the pathophysiology of stimulus-induced drop episodes (SIDEs) is not well understood, there is no definite therapy for those episodes.
  
  
  METHODS
  We report a 15-year-old female with stimulus-induced drop episodes occurring many times a day that resulted in failure to perform her daily activities. Because her SIDEs were misdiagnosed as atonic seizures, she was treated with several antiepileptic drugs, including valproic acid, levetiracetam, lamotrigine, primidone, carbamazepine, and clobazam.
  
  
  RESULTS
  We realized that her clinical and radiological findings, together with SIDEs, are compatible with Coffin-Lowry syndrome. All of her medications were discontinued following the diagnosis of SIDE, and she was started on clonazepam. After treatment, she became more independent and was able to perform her daily activities. Subsequently, her episodes decreased from 3 times a day to 1-2 times a month. Sodium oxybate and fluoxetine were added to the treatment protocol without remarkable improvement. Her genetic analysis revealed a heterozygous variation of CLS.
  
  
  CONCLUSIONS
  We conclude that SIDE should be included in a differential diagnosis of epileptic seizures in patients with CLS and that clonazepam is an effective choice in the treatment of SIDEs.
authors: Department of Pediatric Neurology, Hacettepe University Children's Hospital, Ankara, Turkey.
authors: Elif Acar
authors: EA
authors: Arslan
authors: Department of Molecular Biology and Genetics, Intergen Genetics Center, Ankara, Turkey.
authors: Serdar
authors: S
authors: Ceylaner
authors: Department of Pediatric Neurology, Medipol University Medical School of Medicine, Istanbul, Turkey.
authors: Güzide
authors: G
authors: Turanlı
keywords: Clonazepam; Coffin–Lowry syndrome; Stimulus-induced myoclonus