Hyperekplexia
| Hyperekplexia | |
|---|---|
| Other names | Exaggerated surprise, exaggerated startle response, startle disease |
| Mutations of the neuroreceptor glycine receptor subunit alpha-1 (GLRA1) can cause hyperekplexia. | |
| Pronunciation |
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| Specialty | Neurology |
| Symptoms | Increased startle response to sudden auditory, visual, or tactile stimulation |
| Complications | Increased alcohol and drug use |
| Duration | Chronic |
| Causes | Mutation of either the GLRA1 gene, GLRB gene, SLC6A5 gene, X-linked (ARHGEF9) gene, or GPHN gene |
| Medication | Clonazepam, diazepam, or phenobarbital; carbamazepine; 5-hydroxytryptophan; phenytoin; valproate; piracetam |
| Frequency | 1 in 40,000 |
Hyperekplexia (/ˌhaɪ.pər.ɛkˈplɛk.si.ə/; "exaggerated surprise") is a neurological disorder characterized by a pronounced startle response to tactile or acoustic stimuli and an ensuing period of hypertonia. The hypertonia may be predominantly truncal, attenuated during sleep, or less prominent after one year of age.
Classic hyperekplexia is caused by genetic mutations in a number of different genes, all of which play an important role in glycine neurotransmission. Glycine is used by the central nervous system as an inhibitory neurotransmitter. Hyperekplexia is generally classified as a genetic disease; some disorders can mimic the exaggerated startle of hyperekplexia.