Tags: Disease.
Hyperekplexia (exaggerated surprise) is a neurologic disorder classically characterised by pronounced startle responses to tactile or acoustic stimuli and hypertonia. The hypertonia may be predominantly truncal attenuated during sleep and less prominent after a 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.