Startle Disease of Hyperekplexia

Hyperekplexia is an exaggerated startle to external stimuli associated with generalized increase in tone seen in a normal newborn with both sporadic as well as genetic predisposition. This is an uncommon neurological entity that is often confused with seizure in infancy. To date about 150 cases have been reported in the literature. We report a 6-week-old infant with characteristic intermittent generalized tonic spasm misdiagnosed as seizure disorder and was on phenobarbitone. With characteristic stiffening episode and exaggerated startle without habituation on tapping the nose we came to a clinical diagnosis of Hyperekplexia or Stiff baby syndrome or Startle disease. The child was started on Clonazepam to which he responded remarkably with decreased startle reflex. The aim of this case reporting is to through insight to this disease entity when we see an intermittent hypertonic infant.

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A Novel Glycine Receptor Variant with Startle Disease Affects Syndapin I and Glycinergic Inhibition

Journal of Neuroscience ◽

10.1523/jneurosci.2490-19.2020 ◽

2020 ◽

Vol 40 (25) ◽

pp. 4954-4969 ◽

Cited By ~ 1

Author(s):

Georg Langlhofer ◽

Natascha Schaefer ◽

Hans M. Maric ◽

Angelo Keramidas ◽

Yan Zhang ◽

...

Keyword(s):

Glycine Receptor ◽

Startle Disease ◽

Glycinergic Inhibition

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Startle disease, or hyperekplexia: Response to clonazepam and assignment of the gene (STHE) to chromosome 5q by linkage analysis

Annals of Neurology ◽

10.1002/ana.410310615 ◽

1992 ◽

Vol 31 (6) ◽

pp. 663-668 ◽

Cited By ~ 89

Author(s):

Stephen G. Ryan ◽

Stephanie L. Sherman ◽

Joseph C. Terry ◽

Robert S. Sparkes ◽

M. Cristina Torres ◽

...

Keyword(s):

Linkage Analysis ◽

Startle Disease ◽

Chromosome 5Q

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The K276E Startle Disease Mutation in the Glycine Receptor: Effects on Channel Gating

Biophysical Journal ◽

10.1016/j.bpj.2010.12.2558 ◽

2011 ◽

Vol 100 (3) ◽

pp. 433a

Author(s):

Mirko Moroni ◽

Remigijus Lape ◽

David Colquhoun ◽

Andrew J.R. Plested ◽

Lucia G. Sivilotti

Keyword(s):

Glycine Receptor ◽

Channel Gating ◽

Disease Mutation ◽

Startle Disease

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Molecular mechanisms of glycine transporter GlyT2 mutations in startle disease

Biological Chemistry ◽

10.1515/bc-2011-232 ◽

2012 ◽

Vol 393 (4) ◽

pp. 283-289 ◽

Cited By ~ 5

Author(s):

Victoria M. James ◽

Jennifer L. Gill ◽

Maya Topf ◽

Robert J. Harvey

Keyword(s):

Startle Response ◽

Molecular Mechanisms ◽

Glycine Receptor ◽

Welfare Impacts ◽

Startle Disease ◽

Glycine Transporter ◽

Tactile Stimuli ◽

Genes Encoding ◽

Muscle Hypertonia ◽

Α1 Subunit

Abstract Startle disease affects newborn children and involves an exaggerated startle response and muscle hypertonia in response to acoustic or tactile stimuli. The primary cause of startle disease is defective inhibitory glycinergic transmission due to mutations in the postsynaptic glycine receptor (GlyR) α1 subunit gene (GLRA1). However, mutations have also been discovered in the genes encoding the GlyR β subunit (GLRB) and the presynaptic glycine transporter GlyT2 (SLC6A5). GlyT2 mutations have also been detected in Belgian Blue cattle and Irish Wolfhounds, where they have significant economic and animal welfare impacts.

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