title: Hyperekplexia: a Chinese adolescent with 2 novel mutations of the GLRA1 gene.
abstract: Hyperekplexia is a rare neurologic disorder, characterized by excessive startle response to unexpected stimuli. There are 3 cardinal features: generalized stiffness immediately after birth that normalizes during the first year of life; excessive startle reflex to unexpected (particularly auditory) stimuli; and a short period of generalized stiffness following the startle response while patient cannot elicit voluntary movements. Awareness of this condition will avoid misdiagnosis of disorders like epilepsy. Clonazepam is an effective medical treatment. We report a patient whose frequent falls triggered by sudden noise or tactile stimuli was initially misdiagnosed as epilepsy. The clinical diagnosis was subsequently revised to hyperekplexia and confirmed by mutation analysis of the GLRA1 gene, which showed c.497G>C (p.Cys166Ser) and c.526delG (p.Asp176Metfs*16). Both of them are novel mutations. His response to clonazepam is dramatic and has been able to engage in sports and social activities.
authors.affiliation: 1Private Practice, Hong Kong.
authors.forename: Keung Kit
authors.initials: KK
authors.lastname: Chan
authors.forename: Sharon Wan-Wah
authors.initials: SW
authors.lastname: Cherk
authors.forename: Hencher Han-Chih
authors.initials: HH
authors.lastname: Lee
authors.forename: Wing Tat
authors.initials: WT
authors.lastname: Poon
authors.forename: Albert Yan-Wo
authors.initials: AY
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D044466:Asian People; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D018009:Receptors, Glycine / Q000235:genetics*; D016750:Stiff-Person Syndrome / Q000235:genetics*
chemical_list: C000657604:GLRA1 protein, human; D018009:Receptors, Glycine
keywords:   GLRA1 gene; clonazepam; excessive startle response; head retraction reflex; hyperekplexia; neurogenetic